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Metallurgy of Continuous Casting Technology - Thoguluva Raghavan Vijayaram (Vol 58, No. 7, July 2012, Page 39 to 50)
In continuous casting process, metal is melted in a furnace and transferred in a tundish. Pouring is accomplished through ceramic piping, and the tundish is covered to prevent oxidation of the metal. From the tundish, it is released into a mould. As the metal cools and solidifies, usually aided with water cooling systems, which surround the mould, finished cast metal protrudes from the far end of the mould. Torches can be used to cut the metal off at set lengths as desired. This technical paper discusses the continuous casting process, mechanism and control, hydrodynamics, heat transport, thermal analysis, solidification control and heat transfer, continuous cast product types, range of sections, and advantages of continuous casting technology for ferrous and non-ferrous foundries.
- August 16, 2012
Oxide Reinforced Ferrous Composites - R. R. Dash, , A. K. Chakrabarti, and P. S. Mukherjee (Vol 58, No. 7, July 2012, Page 35 to 37)
Most of the work reported in the literature relates to carbide dispersion in cast iron and steel matrix. There is a scope to investigate the feasibility of oxide dispersion in steels and determine its effect on the structure and properties. In this work, preparation of oxide reinforced composites have been attempted by smelting reduction of red mud – charcoal briquettes in a pool of liquid steel.
- August 16, 2012
Magnesium Treatment Processes for the Production of Ductile Irons and Practical Tips - S. K. Paknikar (Vol 58, No. 7, July 2012, Page 29 to 34)
The magnesium treatment is a vital process in ductile iron production and so has been extensively deliberated in many seminars and conferences. The author has studied various practices followed by various small, medium and large foundries and has offered some practical tips towards energy conservation and cost-cutting.
- August 16, 2012
Strategies for Growth of Indian Foundry Industry - V. S. Saravanan (Vol 58, No. 7, July 2012, Page 23 to 28)
All of us are aware that India is currently in position number 2 in the casting production worldwide, but compared to China the gap is nearly about 27 million metric tonnes. Though it is difficult to narrow down the gap, to achieve 20 million metric tonnes of casting production in the year 2020, it is being planned to pump 20,000 crore rupees in Indian foundry industry. However, unless the industry operating system is regulated with technological upgradations, it is difficult to achieve this target.
- August 16, 2012
Selection of Performance Measurement Metrics for Foundry Supply Chains - Brijesh Ainapur, Ritesh Kumar Singh, and P. R. Vittal (Vol 58, No. 6, June 2012, Page 44 to 51)
Many foundries are operating at lower levels than the installed capacities. More emphasis is given on technical up-gradation and automations in the plant when compared to supply chain performance measurement system. Study on 56 foundries across India has shown that only 68% of installed capacities are being utilised. This is mainly because of lack of co-ordination among the supply chain partners. This gap can be easily filled by properly identifying the supply chain performance measurement (SCPM) metrics with a suitable framework. Field of Supply Chain Management (SCM) witnessed rapid growth in recent past and proved to be a successful tool for organisations growth. uccess of supply chain improvement initiative lies in selection of appropriate Key Performance Indicators (KPI’s) using best suitable supply chain framework. These performance indicators are to be measured, monitored and controlled with proper review mechanism.
- July 30, 2012
Holistic, Perspective and Requirements of EMS in Foundry Industry - Priyavrat Thareja (Vol 58, No. 6, June 2012, Page 35 to 43)
Environmental management is not merely a requirement of law but a necessity of life. If there are pollutants, there is chaos. All facilities, infrastructure, technologies et al., which threaten life and business process on Safety, Health, Environment and Quality (SHEQ) must be shunned, since they can be terminal for the facility. It is so, because it defies the purpose of its existence
- July 30, 2012
Experimental Investigations and Modelling of Specific Fuel Consumption of Rotary Furnace - R. K. Jain (Vol 58, No. 6, June 2012, Page 28 to 34)
This paper deals with modelling and optimisation of specific fuel consumption in a LDO-fired rotary furnace using feed forward modelling method of artificial neural network (ANN).The authors conducted experimental investigations on fuel consumption in a rotary furnace in an industry. It was observed that 6% oxygen enrichment of the air preheated upto 4600 C simultaneously with reduction of air volume to 75% of its theoretical requirement lowered the specific fuel consumption to 0.260 lit/kg. The compact heat exchanger with 533 fins was used for preheating the air. Accordingly, the emission level was also considerably reduced. The feed forward modelling method of artificial neural network contained in MATLAB software was used for modelling and optimisation of specific fuel consumption. The percentage variation between actual experimental data and modelled result was -0.52% for 6% oxygen enrichment which is fairly acceptable.
- July 30, 2012
A Practical Approach of Inoculation Process – A Mandatory Step in Grey Iron Melting - D. S. Padan (Vol 58, No. 6, June 2012, Page 23 to 27)
The term inoculation in metallurgy is defined as a process of adding small quantity of ferroalloys to liquid metal which makes significant changes in the microstructure and mechanical properties of the solidified component without affecting much the final chemistry. In cast iron metallurgy, it is an unavoidable process. Inoculation plays a distinct role in modification of graphite morphology and improvement in mechanical properties of grey cast iron. It facilitates the nucleation process by formation of additional heterogeneous nuclei insisting solidification to take place at higher temperature. This results formation of high degree of desired graphite morphology, freedom from mottled and chilled (white iron) casting edges, uniformity and consistency in microstructure, high strength etc in both flake and spheroidal graphite irons. Various types of inoculants consisting of different elements either alone or in combined form are used, of which silicon-based inoculants are most common for its effectiveness as well as low cost. The type of inoculant, quantity, time of addition, fading tendency etc. controls the final property of the casting. Although inoculation process is followed as a mandatory step by Grey iron Foundry practitioners, occasionally a gap is observed in understanding the importance and need of same. Through this paper, it has been tried to bridge the gap and provide foundrymen the practical approach of inoculation process in grey iron melting which may be useful for the production of metallurgically sound castings.
- July 30, 2012
Cost Reduction Through Small Improvements - R. Santhanam (Vol 58, No. 5, May 2012, Page 49 to 52)
In the market scenario, costs are increasing by every week/month/year but customers are not willing to pay the increased price. The customers are also facing the same problem and a vicious circle. The MANTRA to all is how to contain/reduce the cost to maintain the bottomline or in other words the profits. The presentation is based on the experience of the author as to how the price pressure was managed and improvements carried out resulting in cost reduction. This has straight away added to the contribution. Two areas of improvements viz. process improvement energy & fuel savings are highlighted in the presentation.
- June 30, 2012
Microstructure, Hardness and Wear Characterisation of Al-Si FGMs - Kiran Aithal S., Vijay Desai, Narendranath N. and P. G. Mukunda (Vol 58, No. 5, May 2012, Page 39 to 48)
FGMs (Functionally Graded Materials) are materials whose structure, composition and morphology vary smoothly from one end of the specimen to the other end. These transition profiles are predesigned and intentional in order to achieve the desired properties. This work attempts to use the concept of centrifuging to produce the solid cylinder FGMs of Al-Si alloy. The FGMs produced are having a wear resistance with considerable strength. It’s a material of heterogeneous microstructure in which a high volume fraction of Si hard particles is dispersed at the surface, where better wear properties are needed, and a gradually decreasing lower volume fraction of Si hard particles below the surface where better strength and ductility are desired has been achieved
- June 30, 2012
A Study on Melting Practice of High Nitrogen Superaustenitic Stainless Steels Using Conventional Induction Melting Technique - J. Anburaj, A. Chandrasekar, B. Anandavel, R. Narayanan and S.S. Mohamed Nazirudeen (Vol 58, No. 5, May 2012, Page 31 to 38)
Superaustenitic stainless steels (SASS) are a group of austenitic stainless, which contain higher amount of Cr, Ni, Mo and N than the conventional austenitic stainless steels. Demand of these alloys for use in harsh environments has tremendously increased, especially in the last decade, due to their excellent pitting resistance and good mechanical properties. Due to the presence of high nitrogen, these steels have to be produced under the controlled atmosphere or controlled melting practice. Presently, these steels are produced by secondary melting techniques like VAR, ESR or degassing processes with high melting cost. The melting of these alloys by induction melting is scanty and is not standardised yet. In the present research, six different compositions of SASS were produced using air induction melting furnace. At each of the alloys, the loss of alloying elements was calculated by charge calculations. The effect of alloying elements on nitrogen solubility was studied experimentally and the same was also validated thermodynamically using Thermo-Calc software. The alloys containing high nitrogen showed higher strength and comparable toughness in the solution-annealed condition when compared to the alloys with low nitrogen content.
- June 30, 2012
Austempering Heat Treatment of Low Carbon Equivalent Ductile Irons - S. S. Umale, P. P. Parhad, Ajay Likhite and S. U. Pathak ( Vol 58, No. 5, May 2012, Page 23 to 30)
The microstructure and mechanical properties of ductile iron (DI) can be greatly altered by properly designing the process parameters of austempering heat treatment. Most studies have been carried out on the microstructural characteristics of ADI (conventional grades alloy 2) and their structure-property correlations, but very limited information is currently available on austempering of low carbon equivalent (CE) ductile iron (alloy 1). The present investigation is undertaken to evaluate the influence of austempering process (i.e. optimisation of austempering time and temperature) on the microstructure and hardness of this material. Cylindrical specimens were austenitised at 900°C for 1 h and austempered at 250 and 500°C for time duration of 1 to 8 h. The present material exhibits the typical microstructure evolution during austempering treatment as a function of time and temperature. At the same time, amount of carbon-enriched austenite is changed. Austempering at lower temperatures results in very fine ferrite needles and thin layers of austenite between them. On the other hand, austempering at higher temperatures results in very coarse and feathery ferrite and relatively large amount of bulky austenite. The microstructure of the as-cast alloy 1 material is pearlitic. Maximum hardness
- June 30, 2012
Micro Improvements Lead to Macro Benefits - S. G. Khanolkar (Vol 58, No. 4, April 2012, Page 36 to 43)
A good mould scheme is the key to reducing recurring costs and wastages in foundry. All the issues mentioned here need to be addressed before actual tool manufacturing is started. Thinking does not cost. It helps more if it is done proactively. Under so-called delivery pressures, thinking generally gets back seat. This should be avoided. Application of mind is mankind’s greatest tool to overcome the challenges one comes across in any situation
- May 30, 2012
Improve Your Sand System for Large-Scale Benefits - Sanjay Karkhanis (Vol 58, No. 4, April 2012, Page 32 to 35)
Foundry industry uses various sand systems for mould making and core making. Sand is one of the most important variables in foundries. The ecological restrictions on sand mining and multifold growth in foundry activities have made sand availability a matter of concern. Ecological concerns are forcing sand mines to be closed. Such unprecedented sand shortage will force foundries to optimise and improve their usage of sand. An attempt has been made in this paper to highlight how sand quality can be improved by processing of raw sand. May 30
- May 30, 2012
Wear Properties of Aluminium (7075)-Based Metal Matrix Composites Reinforced with Fly Ash Particulates - M. Sreenivasa Reddy, Soma V. Chetty, Sudheer Premkumar and A . N. Khaleel Ahmed (Vol 58, No. 4, April 2012, Page 29 to 31)
Metal Matrix Composites reinforced with ceramic phase have become of great interest because of the combined effects of metallic and ceramic materials relative to the corresponding Monolithic alloys. Hence MMCs can be alternatives to conventional materials in a number of specialised application areas. Numerous studies have examined the effect of contact load on the wear resistance of various MMCs under dry sliding conditions. It has been demonstrated that Aluminium matrix composites reinforced with various discontinuous reinforcement materials have potential for application in both automobile and aerospace industries. In the present investigation, efforts are made to study the wear properties of as-cast metal matrix composite of AA7075 reinforced with fly ash particulates of 200 microns in different compositions. The vortex method of stir casting was employed, in which the reinforcements were introduced into the vortex created by the molten metal by means of mechanical stirrer. Castings were machined to the ASTM standards on a highly sophisticated lathe. The wear resistance of MMCs is strongly dependent on the kind of reinforcement as well as its volume fractions. Severe wear occurs on unreinforced compared to reinforced MMC alloys. Sliding distance has an effect on the transition wear condition. The addition of reinforcement delays he severe wear transition.
- May 30, 2012
Flow Rates in Multi-Gate Systems : Experimental and Simulation Studies - K.H. Renukananda, Akash Chavan and B. Ravi (Vol 58, No. 4, April 2012, Page 23 to 27)
Mould filling takes the shortest time in the lifecycle of a cast product, yet exerts the most influence on its quality. Complete, smooth and uniform filling of mould with clean metal is achieved by an appropriate gating system, which comprises one or more pouring basins, sprues, runners and gates. The number, location, shape and size of the gating elements determine the sequence and rate of flow of molten metal into the mould cavity. There are however, no mathematical models to estimate the discharge and volume of flow through each gate. This is needed to balance the flow through multiple gates (by adjusting their position and cross-sectional area), and to ensure that the mould cavity is filled in an optimal time. In this work, we present experimental and simulation studies on discharge through multiple gates connected to a horizontal runner. Experiments are conducted by tap and collect method using water and the volume of flow through each gate is observed for two different setups: end-sprue and centre-sprue. The results are compared with computer simulation, providing valuable insights useful for designing multi-gate systems.
- May 30, 2012
Metal Casting Innovations, 1952-2012 and Beyond . . . . – A Personal View-Merton C. Flemings (Vol. 58, No. 3, March 2012, Page 51-57)
- April 30, 2012
Micro Steps in Foundry Shop-Floor Could Enhance the Productivity of Foundry : A Few Case Studies- Goutam Sutradhar (Vol. 58, No. 3, March 2012, Page 44-47)
Production of quality castings at competitive rates has become the global scenario. Shop-floor supervisors usually take all efforts to minimize rejections. Author has taken his personal efforts to carry out such type of corrective actions in the shop-floor so that the amount of quality castings could be enhanced in terms of tonnage. In this paper, ten case studies are discussed where micro-level corrective actions could enhance the quality / productivity of the organisation even without any type of capital investment.
- April 30, 2012
Modelling, Optimisation and Simulation of Rotational Speed, Fuel Consumption and Melting Rate in Rotary Furnace- R. K. Jain and Ranjit Singh (Vol. 58, No. 3, March 2012, Page 37- 43)
The rising demand for high quality castings necessitates that vast amount of manufacturing knowledge be incorporated in manufacturing systems. Rotary furnace involves several critical parameters like flame temperature, preheat air temperature, rotational speed of the furnace, excess air percentage, melting time, fuel consumption and melting rate of the molten metal which should be controlled throughout the melting process. A complex relationship exists between these manufacturing parameters and hence there is a need to develop models which can capture this complex interrelationship and enable fast computation. In this paper, the applicability and the relative effectiveness of regression and numerical technique for modelling and optimisation of rotary furnace parameters have been investigated. The results obtained by these models are found to correlate well with the experimental data obtained from the rotary furnace.
- April 30, 2012
Evaluation of Corrosion Resistance and Hardness of Al-Mg-Si Based Hybrid Composite- H. Ghanashyam Shenoy, Soma V. Chetty, Sudheer Premkumar, A. N. Khaleel Ahmed and M. Sreenivasa Reddy (Vol. 58, No. 3,March 2012, Page 33-36)
MMCs can be alternatives to conventional materials in a number of specialized application areas. It has been demonstrated that aluminium matrix composites reinforced with various discontinuous reinforcement materials have potential for application in both automobile and aerospace industries. So,efforts are made to study the hardness and corrosion resistance of Al-6061 hybrid composite containing mica particulates of 200 microns and short eglass fibres of 2-3 cm length in different compositions. Vortex type of stir casting was employed in which reinforcements were introduced. The test specimens were machined to ASTM standards and heat treatment was carried out. The specimens were subjected to solution heat treatment with a soaking time of 2 hours and then quenched in SAE 30/40 grade oil. Artificial ageing was carried out at 1750C for duration of 24 hours. A degree of improvement in both hardness and corrosion resistance was observed in artificial aged casting over solution heat-treated and as-cast condition. Corrosion test was carried out with 0.1 normal HCL and 5% NaCl solutions.
- April 02, 2012
Modelling and Optimisation of Variables Affecting Specific Fuel and Energy Consumption in LDO-Fired Rotary Furnace - R. K. Jain and D. K. Chaturvedi (Vol. 58, No. 2, Feb 2012, Page 50-53)
This paper deals with modelling and simulation of oxygen consumption for enrichment of preheated air in LDO-fired rotary furnace for optimal specific fuel and energy consumption using regression modelling method and artificial neural networks. The authors conducted experimental investigation on oxygen enrichment of preheated air in a rotary furnace in an industry. The maximum percentage variation between actual experimental and modeled results is found to be +0.27453% which is well within the permissible limits.
- April 02, 2012
Performance Evaluation of Characteristics of Thermally Sprayed Industrial Ceramic Coatings-Mohammed Yunus, J. Fazlur Rahman and A. N. Khaleel Ahmed (Vol. 58, No. 2, Feb 2012, Page 43-49)
The design of an engineering surface is concerned with preparing a surface with suitable modifications, so as to meet the functional requirements of the engineering components. Among several surface modification techniques, plasma spraying and high velocity oxy-fuel (HVOF) spraying techniques are more precise and widely used for many advanced industrial applications. Thermally-sprayed coatings give high strength at elevated temperatures, wear resistance, resistance to chemical reaction, and also corrosion protection on engineering components. However, the quality and functional requirement of ceramic coatings can further be improved by eliminating the presence of cracks and defects in the coatings by suitable post-processing technique (microwave glazing). In this paper, an attempt has been made to study various mechanical and tribological characteristics of tungsten carbide cobalt (WC-CO) HVOF coating as well as Atmospheric Plasma Spraying (APS) ceramic coating, used in different coatings. An experimental study is also formulated to evaluate an important mechanical characteristics such as porosity, bond strength, hardness and tribological characteristics, including fatigue behaviour of the coated components. This paper also highlights a novel post-processing technique of ceramic coatings by microwave glazing to improve the performance of engineering surfaces by achieving high quality coatings.
- April 02, 2012
Copper in Gray Cast Iron-Vivek Kumar, Evgeniy D. Golovin, Anatoly A. Bataev and Viktor A. Kuznetsov (Vol. 58, No. 2, Feb 2012, Page 38-42)
Present work was intended to investigate friction properties, chilling tendency and microstructure changes in gray cast iron (GCI) on addition of 5, 10 and 15 wt.% Cu. Friction properties were tested using commercial grease LiTioL-24 as lubricant at two disk velocities- 100 and 300 rpm, under normal load range of 100 N to 2000 N. For comparison of anti-friction properties of GCI and copper-added GCI with bronze, Cu-10 wt.% Pb was taken as standard material (Std. Mat.). Chilling tendency in GCI and copperadded GCI was studied. Microstructure of materials was studied under optical microscopy (OM) and scanning electron microscopy (SEM). Copperadded GCI exhibited better anti-friction property in comparison to GCI and Std. Mat., specifically at 300 rpm disk velocity. Copper addition favoured chilling tendency and it increased with increasing copper content. It was observed in OM and SEM that copper got alienated out inside GCI forming an intermediate layer at the interface.
- April 02, 2012
Improving the Quality of Green Sand Castings to Minimise the Defects Using Artificial Neural Network- S. S. Mohamed Nazirudeen and B. Nagasivamuni (Vol. 58, No. 2, Feb 2012, Page 32-37)
Green sand moulding technique is the most popular of all moulding methods and accounts for more than 90% of sand-moulded castings. The quality of castings produced from the green sand mould is greatly influenced by the properties of moulding sand. Several types of defects may occur during casting due to improper moulding sand conditions, considerably reducing the total output of castings. Hence, in the present work, an attempt has been made to create a neural network model to prevent the defective castings produced, with properties such as green compression strength, green shear strength, moisture content, permeability, compactibility and mould hardness as inputs and the percentage defects produced as output. The neural network is trained with the data collected from cast iron foundry. After the training was over, the set of inputs of the casting that were to be made were fed to the network and the network could predict the percentage defectives. The actual outputs were found to be in good agreement with the predicted values.
- April 02, 2012
Factors Influencing Grain Refining Behaviour of Master Alloys and Their Study on Fading and Poisoning Phenomena in Al and Its Alloys- P. C. Meena, Surendra Singh and Ashok Sharma (Vol. 58, No. 2, Feb 2012, Page 23-31)
Al-Ti-B grain refiners are well-established and generally perform better than Al-Ti alloys. Because of the importance of Al-Ti-B alloys, most studies have been carried out with this system. The performance of grain refiners is very sensitive to the alloying elements present in aluminium. For example, small amounts of zirconium have been found to poison Al-Ti-B master alloys and render them much less effective. Al-Ti-C master alloys are new generation grain refiners which are free from agglomeration and poisoning problem as faced with Al-Ti-B master alloys. The growth restricting role of solute Ti is generally accepted, but the nature of the substrates upon which heterogeneous nucleation occurs is still unclear. The present paper has critically reviewed and discussed various aspects of grain refinement in Al and its alloys.
- April 02, 2012
Feeding of Hollow Cylindrical Castings - P. K. Sandell (Vol. 58, No. 1, Jan 2012, Page 43-48)
The paper deals with the methodology and the manufacturing process used to successfully develop a long cylindrical casting, called the Hollow Shaft. Both experience as well as a rough estimate of the Niyama Criterion indicated strong possibilities of a centreline shrinkage. The methodology was based on (1 ). The Shape Factor and Feeding Distance Formulae specified in the SFSA Feeding and Risering Guidelines for Steel Castings1, (2) Use of a padding and (3) Heuver’s circle method. A formula for assessing the length of the critical mushy zone derived from the Niyama Criterion has been developed. The hollow cylinder was cast without any internal or external defects.
- March 02, 2012
Competitive Foundry Through Integration of TIPS (Technology, Innovation, Product Design and Process Systems) - Priyavrat Thareja (Vol. 58, No. 1, Jan 2012, Page 37-42)
Development of a sound product which satisfies given criteria is a common challenge. The domain of competition is quite large because foundries compete inter-manufacturing and intra-firm, producing nearnet shapes. The customer desires a component which promises functions most reliably, while addressing socio-techno-environmental attributes. This work is designed to bring out the issues challenging foundrymen and how one shall react to rendering a programme to meet them. The various options embrace around TIPS and contemplate to take up specific issues and challenges in founding inter-manufacturing scenario. How the various producers react in addressing the issue will form a subject of next industry review which usually contemplates technology evaluation. The paper concludes that frequent innovations in foundry practice be brought about, at close intervals such as to sustain continual manufacturing competence.
- March 02, 2012
Recycling of Investment Casting Wax and Improvement of Its Properties – Exploring Possibilities - D. N. Shivappa, A. J. K. Prasad and S. Arjun Rao Pole (Vol. 58, No. 1, Jan 2012, Page 34-36)
This paper briefly presents how investment casting wax was developed, with a summary of structure, categories of investment casting wax available, properties and wax pattern production. Possibilities of improving the recyclability of the wax are briefly discussed.
- March 02, 2012
Effect of Mechanical Vibration on the Properties, Microstructure and Fractography of Titanium Carbide Particulate-Reinforced LM6 Alloy Composite Castings - Thoguluva Raghavan Vijayaram1, Sayuti M. and S. Sulaiman (Vol. 58, No. 1, Jan 2012, Page 23-33)
This research paper discusses on the manufacturing, mechanical testing, metallography, and fractography of titanium carbide particulate-reinforced aluminium-11.8% silicon alloy composite castings. Titanium carbide particulate-reinforced composites were fabricated by vibration moulding sand casting technique. Composite castings in the form of a slab containing 0.2, 0.6, 1, and 2% weight fraction of titanium carbide particulate equally reinforced in the LM6 alloy are made by vibration moulding sand casting process with frequencies of 10.2 Hz, 12 Hz and 15 Hz. The results showed that the impact strength and hardness of the composites increased with an increase in the frequency of vibration and increasing titanium carbide particulate reinforcement in the LM6 alloy matrix composites. The thermal conductivity and diffusivity of the processed composites were determined. Increasing frequency of vibration and titanium carbide content helps to improve density, thermal conductivity, thermal diffusivity and purification of the grain boundaries. The dispersed particles increased the thermal conductivity and diffusivity according to an effective media theory. This paper also focuses on the mechanical properties of titanium carbide particulate-reinforced aluminium-silicon alloy matrix composite subjected to mould vibration during solidification. Mechanical properties such as tensile strength, hardness, are determined and microstructural features are analysed through SEM. Besides, fracture surface analysis has been performed to characterise the morphological aspects of the test samples after tensile testing. Preliminary works show that the mechanical properties have been improved with 10.2Hz frequency when compared with the gravity diecastings without vibration
- March 02, 2012
Optimisation of Structure-Property of Thin-Wall Austempered Ductile Iron- Saroj Kumar, D. J. Gawai, D. N. Prasad and K. K. Singh (Vol. 57, No. 12, December 2011, Page 29-42)
Many cast parts are currently produced in Aluminium rather than cast iron, because of the drive to get high strength /weight ratio for application in automobile and aerospace. Ductile Iron casting of approximately 2-3mm section thickness better known as Thin-Wall Ductile Iron (TWDI) having high strength /weight ratio and better mechanical properties than aluminium alloys. The austempering treatment of these TWDI components may further lead to improvement in the strength/weight ratio and will be a suitable and economical alternative to use in automobile parts. The effect of various parameters like, gating and feeding, pouring temperature, post inoculation on the structure and properties of TWDI were studied and it was observed that for thin plates decreasing in pouring temperature leads to finer pearlitic structure and increase in hardness. The increase in inoculation percentage leads to increase in the nodule count, decrease in nodule size and increase in volume fraction of ferrite. Gating and feeding design effect was analysed by using simulation software “ProCAST” and actual casting. It was found that the casting with suitable design and location of riser eliminates the formation of chills and reduces the difference in nodule count at various sections. As expected, the hardness increased with decrease in section thickness. Short-term austempering treatment was used to obtain thin-wall ADI castings. The samples of 2 and 3 mm thickness were austenitised at 900 °C for 30 minutes followed by holding at 350°C, 400°C and 450°C for 5, 15, 30 and 60 minutes for each temperature. The microstructures and mechanical properties were analysed in respect of various process parameters like austempering time, austempering temperature and section thickness.
- January 30, 2012
Dry Sliding Wear Behaviour of Hypereutectic Al-15Si and Al-15Si-4Cu Cast Alloys by Melt Treatments- P. V. Chandra Sekhar Rao, A. Satya Devi and K. G. Basava Kumar (Vol. 57, No. 12, December 2011, Page 23-28)
The microstructures and dry sliding wear behaviour of hypereutectic Al-Si and Al- Si-Cu cast alloys were studied after various melt treatments like refinement, modification and grain refinement. Dry sliding wear tests were conducted for varying speeds from 1 m/s to 3 m/s in steps of 0.5 m/s for a constant sliding distance of 1000 m and at constant load of 60 N. Wear tests were also conducted for varying loads from 20 N to 100 N for a constant sliding distance of 1000 m and at constant velocity 1 m/s. The results suggest that wear resistance decreases with increasing load and increase in the sliding speed of the pin decreases the wear volume, wear rate and coefficient of friction of the cast alloys. These cast alloys exhibited more wear resistance when the sliding speed of the pin is increased.
- January 30, 2012
Experimental Investigations for Identification of Input Parameters for Optimal Flame Temperature, Emission Level and Energy Consumption of LDO-Fired Rotary Furnace- R. K. Jain (Vol. 57, No. 11, November 2011, Page 36-41)
The LDO-fired Rotary Furnace is used for production in ferrous foundries. Our country is passing through an environmental awareness and energy crisis. The natural sources of energy are depleting fast and researches are going on for renewable and alternate sources of energy. By the time the new sources of energy inputs are available, the approach should be for maximum utilisation of available energy and energy conservation. This paper deals with the extensive experimental investigations carried out on a 200 kg rotary furnace at a foundry in Agra for identification of input parameters which affect the flame temperature, emission level, and energy consumption in ferrous foundries.
- December 28, 2011
Optimisation by Taguchi Design Method of Manufacturing Condition for Semi-Solid Al-Zn-Mg Alloy- Sung Yong Shim, Dae Hwan Kim, In Shup Ahn and Su Gun Lim (Vol. 57, No. 11, November 2011, Page 33-35)
In order to find an optimum condition for semi-solid Al-Zn-Mg system aluminium alloy fabricated by cooling plate method, Taguchi design was used. The cooling plate method that can effectively separate a formed grain from mould wall is able to make a semi-solid material by flowing molten metal over an inclined Cu plate and casting in mould for near-net-shape component. In Taguchi’s design method, it is known that high value of SN-ratio (Signal vs. Noise) is better. So manufacturing conditions were arranged as table of orthogonal arrays L9(34), and then factors determined were pouring temperature and angle of cooling plate. From microstructures observed, grain size and aspect ratio were measured by image analyser. Results seemed that the pouring temperature is main effect on spherical microstructures since SN-ratio which is sensibility on surround environment was the highest. The optimum condition for Al-Zn-Mg alloy was 40 degree of cooling plate, 680oC of pouring temperature. Their values of grain size and aspect ratio were 70¼m, 1.3, respectively.
- December 28, 2011
Parametric Influence on Melting Rate in Rotary Furnace Using Bio-Fuels – A Parametric Study Using Taguchi Method- Ranjit Singh and Purshottam Kumar (Vol. 57, No. 11, November 2011, Page 27-32)
The paper aims to find an efficient way to determine influential factor on the response factor by reducing process or product variability and also minimizing product error by using a relatively small number of experiment and to achieve superior quality product. An experimental investigation into the process parameter is done to have a robust design method for identifying process parameters having the major influence on melting rate in rotary furnace. Minimum number of experiments are planned using Taguchi Method. The variation of several parameters and the interaction between parameters are investigated using orthogonal array technique. An experimental investigation into the process parameter effects using Jatropha as fuel is presented to determine this influence for quality castings. Rotary furnace involves several critical parameters like flame temperature, preheat air temperature, rotational speed of the furnace, excess air percentage, melting time, fuel consumption and melting rate of the molten metal which should be controlled throughout the melting process to produce homogeneous casting of high quality. The relative effect of these variables on melting rate while experimenting using Jatropha oil as fuel is quite complex. Partial factorial design using L9 (34) orthogonal array is used to study the effect of these parameters on melting rate. Having the knowledge of interrelationship between these variables, the manufacturer would be able to select the optimum input parameters which would yield ideal melting rate for producing quality castings.
- December 28, 2011
Studies on Coal-Based Sponge Iron- B. Panja, D. K. Mondal and A. K. Chakrabarti (Vol. 57, No. 11, November 2011, Page 23-26)
Analysis of data collected from a coal-based sponge iron plant suggests that Fe (total) content in iron ore only marginally influences fines generation. The % of fines in the sponge iron produced increases with decrease in mean particle size of iron ore.
- December 28, 2011
A Holistic Approach to Zero Defect Castings- B. Ravi (Vol. 57, No. 10, October 2011, Page 38-44)
Casting rejections – as high as 8-15% in jobbing foundries – cannot be attributed to poor methoding and process variability alone. Most castings are designed for manufacture, not for manufacturability. Many defects like shrinkage porosity, hot tear and cold shut originate from poorly designed part features (isolated junction, constrained internal feature, long thin section, respectively). Foundry engineers partially tackle the problem by tweaking the part design (for example, increasing a fillet radius or padding a thin wall), but incur additional and avoidable costs of machining and productivity loss. Ideally, design for manufacturability (DFM) should be carried out early by product engineers (foresight), instead of late DFM currently practised by casting suppliers (hindsight). Unfortunately, designers lack foundry knowledge, and foundry engineers lack design rights. We present a collaborative system for achieving perfect castings – high quality with frugality–by integrating part, tooling, methods and process optimisation. Feedback loops are provided to capture the associated domain knowledge and reuse it for DFM of new parts. Major control parameters include: wall thickness, junctions and hole diameter (part design phase), parting line, cores and mould cavity layout (tooling design), feeding and gating system (methods design) and process settings (manufacturing). Each subsequent phase provides more information and feedback regarding part quality and cost to product engineer, allowing design improvements for better manufacturability without affecting functionality. A secure web-based project management system enables rapid and seamless collaboration between casting lifecycle engineers. An industrial example is presented to illustrate the working of the system. Direct benefits include: first-time right castings, consistent quality and low cost of tooling and manufacturing. Other benefits include better relations between OEM and supplier, knowledge capture and reuse for future projects, and ease of training fresh engineers.
- November 28, 2011
The RSF Technology for Semi-Solid Casting Processes- Lorenz Ratke, Ashok Sharma and Divya Kohli (Vol. 57, No. 10, October 2011, Page 33-36)
Rapid Slurry Forming (RSF) is a new process for manufacturing of cast components. The process is based on enthalpy exchange between at least two alloy systems having different enthalpies. The aim is to get semi-solid slurry. Experimental work has been done on Al-7Si alloy to get semi-solid slurry. The beauty of the process is that the state of slurry is controlled by relative added amounts of the alloy system used. It is not necessary to accurately control the heat flux to surrounding media such as, crucible or mould. Globular microstructure of primary aluminium dendrites could thus be achieved by RSF process which ensures improved foundry characteristics. The results indicate that the RSF process is suitable for producing high quality metal slurries economically which may be a breakthrough for semisolid casting processes.
- November 28, 2011
Modelling, Optimisation and Simulation of Oxygen Enrichment of Preheated Air for Optimal Specific Fuel and Energy Consumption in LDO-Fired Rotary Furnace- R. K. Jain (Vol. 57, No. 10, October 2011, Page 29-32)
This paper deals with modelling and simulation of oxygen consumption for enrichment of preheated air in LDO-fired rotary furnace for optimal specific fuel (energy) consumption using regression analysis techniques. The author conducted experimental investigation on oxygen enrichment of preheated air in a rotary furnace in an industry. The regression modelling method contained in MatLab software was used for modelling and optimisation. The maximum percentage variation between actual experimental and modelled results is +0.27453% which is well within the permissible limits.
- November 28, 2011
Metal Casting Dies- Thoguluva Raghavan Vijayaram (Vol. 57, No. 10, October 2011, Page 25-28)
Die-castings are the highest produced engineering components in foundries. These cast products are important components ranging from automotive to playing toys. Die-casting is a versatile process for producing engineered metal parts. The liquid metal or alloy is forced under high pressure into reusable metallic moulds in a casting process. Metallic moulds used in die-casting technology are called as casting dies. In this paper, different types of casting dies are discussed. Parts produced by die-casting can be sharply defined with smooth or textured surfaces and are suitable for a wide variety of attractive and serviceable finishes. Die-casters can produce castings in a variety of shapes, sizes and wall thicknesses that are light-weight, strong, durable and dimensionally precise. Die-casting process has been well-researched and systematically quantified in terms of thermodynamics, heat transfer and fluid flow. Design factors causing thermal fatigue should be identified to extend the die life. In die-casting process, die design and die manufacturing costs are high. The main cause of failure of die-casting dies are due to thermal fatigue cracking. This paper explains about the different types of die materials used for die fabrication. Besides, properties of dies, defects in casting dies and die life are discussed. The basics of die construction design and procedures are presented with their constructional features.
- November 28, 2011
Modelling Optimisation and Simulation of Excess Air, and Its Effect on Other Input Parameters for Optimal Specific Fuel and Energy Consumption in LDO-Fired Rotary Furnace- R. K. Jain (Vol. 57, No. 9, September 2011, Page 45-52)
This paper deals with modelling and optimisation of excess air consumption in LDO-fired rotary furnace, using regression analysis techniques. The authors conducted experimental investigation on oxygen enrichment of preheated air in a rotary furnace in an industry. The regression modelling method contained in MatLab software was used for modelling and optimisation. The maximum percentage variation between actual experimental and modelled result is +4.61%, which is well within the permissible limits.
- August 28, 2011
Dross in Ductile Iron: Source, Formation and Explanation- Martin Gagné, Marie-Pierre Paquin and Pierre-Marie Cabanne (Vol. 57, No. 9, September 2011, Page 39-44)
The manufacture of Ductile Iron (DI) castings has to obey basic rules. Although the production of sound castings exhibiting the required mechanical properties is easily achieved, the casting user also asks for a casting skin finish without apparent defects. Defects such as dross and slag affect the surface appearance of the parts but, more importantly, affect the fatigue endurance by acting as initiation sites for the failure. As a result, producing castings free of dross becomes an important challenge for foundries producing either thin-wall or heavy-section castings. This paper presents a study on the formation of dross at different temperatures and chemical compositions. The experience of the Rio Tinto R & D Group, through many investigations carried out on DI samples, has led the researchers to investigate dross formation with a simulation software. It was observed that the formation of dross is directly connected to the level of oxygen while the iron temperature modifies the dross composition. The dross built-up is marginally affected by sulphur and the influence of magnesium and silicon was confirmed.
- August 28, 2011
Determination of Interface Heat Transfer Coefficient (IHTC) for Investment Casting Simulation - A Sensitivity Study- R K Nayak, S Venugopal and M S Velpari (Vol. 57, No. 9, September 2011, Page 34-38)
Complex shape casting with stringent dimensional accuracy for aerospace requirements is manufactured by investment casting process. One of the main difficulties associated with numerical simulation of solidification processes is the lack of thermo-physical properties and/or boundary conditions. Temperature distributions in investment castings and shells are of great influence on the quality of investment castings. To improve the simulation prediction of casting defects, interface heat transfer coefficient (IHTC) between casting and fused silica shell need to be optimized. Sensitivity study of initial IHTC has been studied and it is observed that initial IHTC = 1000W.m-2.K-1 need to be assigned in between casting and fused silica shell to predict the thermal profile as well as defects more accurately. Simulation and experimental analysis have been carried out using the optimized IHTC for an austenitic stainless steel investment casting component. Shrinkage porosity location has been compared between simulated and experimental results. The simulated and experimental shrinkage porosity location matches pretty well.
- August 28, 2011
Light Weight Graphite Particulate Reinforced Aluminium Silicon Alloy Matrix Composite Castings- Thoguluva Raghavan Vijayaram (Vol. 57, No. 9, September 2011, Page 24-33)
Casting of graphite particulate reinforced aluminium-11.8% silicon alloy matrix composites by casting technology has some important advantages and also easier to process. Such composite castings exhibit good bonding between the LM6 alloy matrix and the graphite particulates. It is also possible to manufacture near-netshape castings with lower fabrication cost. Vortex-turbulence generated by stir casting technology is the most promising method for processing graphite particulate reinforced aluminium alloy composite castings because of its adaptability. The special interests in aluminium-11.8% silicon alloy graphite particulate reinforced composites is related to their higher strength, lightweight, hardness, higher temperature resistance and wear resistance than that of any conventional materials. In this experimental work, aluminium-silicon alloy graphite particulate composites containing graphite particulate of 1 %, 2%, 3% and 4% by weight fraction are produced by using the vortex mixing method. The size of the graphite particulate is approximately 124.80 micron supplied by Fluka, USA. This paper discusses the vortex processing technique of graphite reinforced aluminium- 11.8% silicon alloy matrix composites castings. After mixing process, the composite slurry mixture is poured in the grey cast iron mould. Thus, slab-shaped composite castings containing 1 %, 2%, 3% and 4% weight fraction of graphite particulate reinforced aluminium alloy are made. Then mechanical, electrical and thermal properties of the graphite particulate reinforced composite castings are evaluated and the complete data is provided in this research paper. The microstructures of graphite particulate composites are studied at different magnifications and photomicrographs are presented in this research paper to understand the graphite particulate distribution uniformity.
- August 28, 2011
Green Foundry Development Through Casting Simulation and QFD - Amrinder Singh Chahal and Priyavrat Thareja (Vol. 57, No. 8, August 2011, Page 57-62)
The context of providing right value to the customer begins with a holistic objective and a broad vision. The issue of broad vision appears as being devoid of the point focus, but it is a blessing in disguise especially when this asymptotic phenomenon results because of inclusion of multi-customers (like the environment, energy resource, Government et al.) start operating with me-too profile. The present work attempts to collate the issue of combining requirements of secondary founding objective like Green Foundry practicing. The objective here is to emphasise the paradigm of reduction of castings produced. Both weight reduction (of individual piece), and the successful deployment of ‘methods’ can be addressed thus to assure greener founding. The instance of using casting simulation packages has been recommended as the narrow objective, which emerges through a broader focus of SHEQ-PC. The present work builds the conceptual framework for the development of a minimum product weight at lean casting, or, lower metal cast at abating defects. The use of simulation software allows that objective, whose character may be determined by applying the Voice of customer paradigm through fulfilment of Quality Function Deployment (QFD). The QFD tool and the roadmap of lean casting development would be handy in imparting to the foundryman a wherewithal for Green and environment-friendly planning of Founding system.
- September 30, 2011
Neural Networks for Modelling of Specific Fuel Consumption of Rotary Furnace - R. K. Jain (Vol. 57, No. 8, August 2011, Page 48-56)
This paper deals with modelling and optimisation of specific fuel consumption in a LDO-fired rotary furnace using feed forward modelling method of artificial neural network (ANN).The authors conducted experimental investigations on fuel consumption in a rotary furnace in an industry. It was observed that 6% oxygen enrichment of the air preheated upto 4600C simultaneously with reduction of air volume to 75% of its theoretical requirement lowered the specific fuel consumption to 0.260 lit/kg. The compact heat exchanger with 533 fins was used for preheating the air. Accordingly, the emission level was also considerably reduced. The feed forward modelling method of artificial neural network contained in MATLAB software was used for modelling and optimisation of specific fuel consumption. The percentage variation between actual experimental data and modelled result was -0.52% for 6% oxygen enrichment which is fairly acceptable.
- September 30, 2011
Optimisation of Casting Weight Using Box-Behnken Design in Foundry Industry for Energy Conservation - S. Ravichandran, N. Alagumurthi and K. Palaniradja (Vol. 57, No. 8, August 2011, Page 41-47)
The quality and weight of castings from green sand mould is influenced significantly by process parameters like moisture content, bentonite, coal dust and mixing time. In the present study, experiments were conducted to measure the casting weight by varying the process parameters. The corresponding green sand properties viz., green compression strength, permeability, compactibility and mould hardness were measured. Regression analysis was carried out on the experimental data collected based on statistical design of experiments (DOE) to establish the input-output relationship of the process. Box-Behnken design of response surface methodology is used to develop the model for predicting and optimising the casting weight. Analysis of variance (ANOVA) was performed to test the statistical adequacy of the model. The results indicated that moisture content and bentonite determined the weight of castings. The experimental values were in good agreement with the predicted values.
- September 30, 2011
An Innovative Nodulariser for the Production of High Strength S.G. Irons - S. K. Paknikar (Vol. 57, No. 8, August 2011, Page 32-40)
The Spheroidal Graphite/Nodular/ Ductile Iron was invented sixty years back that is in 1950. During last six decades, lots of research works have been done in this field. Initially, it was pertaining to the elements which could be used for spheroidising of graphite from flake graphite. Then after different methods of Magnesium treatment were developed. There were many variations. Some of them are Direct Pour Method, Tundish Cover Method, Plunger Method and Converter Method etc. Present scenario of S.G. Iron is that in last fifteen years, a large number of grey cast iron foundries have been converted to S.G. Iron due to large demand of S.G. Iron castings in Indian as well as in global market. Out of this, there is tremendous requirement of high strength S.G. Iron castings. Keeping this in my mind, the research was done on the development of Nodularizer, which will give high strength S.G. Iron at lower cost. Salient features of this innovative noduliser are discussed in this paper. Industrial heats were taken and results achieved are quite fascinating.
- September 30, 2011
Production Friendly Manufacturing Method of Compacted Graphite Iron - V. S. Saravanan (Vol. 57, No. 8, August 2011, Page 28-31)
Compacted Graphite Iron is also known as CGI or Vermicular Graphite Iron in which the shape of the graphite is neither flake nor spherical, but it has a worm-like graphite with blunt or rounded edges. Compacted-graphite iron possesses some good properties of grey and ductile iron. CGI has twice the strength of grey iron, but less than ductile iron. Grey iron has good damping and thermal conductivity with more brittleness due to the sharp edge of the flakes and ductile iron has a high tensile strength, but relatively poor thermal conductivity and damping properties. Compared with these two materials, CGI has thermal conductivity and damping properties similar to that of grey iron and comparable tensile strengths and stiffness to ductile iron. Also this material is having good anti-seizing property suitable for brake discs, cylinders, cylinder liners etc.The first development was made commercially for disc brakes for the high-speed rail trains in Europe. Initially, they had cast iron disc brakes those were simply not satisfying their requirement. It had a severe heat-checking and cracks which were the potential causes for catastrophic failures. After implementing CGI disc brakes, they had come out of this headache. After that incident, several automotive manufacturers started developing these parts in CGI to meet efficiency and strength requirements. Since more number of articles came out about the properties and metallurgy of CGI, this paper concentrates mainly on the production method of CGI in an easiest and production-friendly way.
- September 30, 2011
Effect of Copper Content and Low Temperature Ageing on Nitinols - Sriram Mukunda, Narendra Nath S. and P. G. Mukunda (Vol. 57, No. 8, August 2011, Page 23-27)
The Ti-Ni-Cu alloy is a well-known Shape Memory Alloy (SMA), which has demonstrated its great potential for a large variety of applications. This alloy is actively applied in the development of new energy conversion systems, and in smart materials system and finds extensive use in medical implants and instruments. In addition to shape memory effects, it has been observed that NiTi and Ti-Ni-Cu SMAs also exhibit superelastic effect near room temperature rendering them the first choice for medical implants and implements. A very successful application of Nitinol is in the field of endodontics because of its unique properties such as high wear resistance, low stiffness, superelasticity and shape memory effect. However, there are conflicting reports about the effect of copper contents of Nitinol and of the effects of ageing temperatures and times that are wholly beneficial in endodontic applications. In this study, three Nitinols with different Copper contents were cast and the effect of low temperature ageing on the microstructure and transformational behavior was investigated.
- August 30, 2011
Internal Defect in Rail Wheel and Its Remedial Measure - M. K. Mukhopadhyay (Vol. 57, No. 7, July 2011, Page 38-40)
Wheels are manufactured in casting route at Rail Wheel Factory/ Bangalore incounter gravity pressure die-casting process in accordance with Griffins Technology. Since the Rail wheels are safety items and suffer dynamic loading, it is essential to ensure soundness of all wheels. Apart from visual examination and magnetic particle testing for its soundness, it is subjected to ultrasonic testing to ensure freedom from internal defect. The wheels are tested ultrasonically on line at rim area, the thickest zone of the wheel, which is prone to develop internal defect. All the wheels are tested by immersion technique where detection and segregation of defectives are automatic. Though the percentage of such rejection due to internal defect is very less,sometimes it shoots up and requires investigation to eliminate rejection. It is obvious that even a single defective wheel in service may cause disaster. This paper deals with the actual type of internal defect observed and reason of occurrence of such defect. The remedial measures to avoid reoccurrence with brief reference to manufacturing process has also been discussed.
- August 30, 2011
Prediction of Mechanical Properties and Lifetime of Thin-walled Aluminium Castings - Olga Polianska and Nataliia Tuchkova (Vol. 57, No. 7, July 2011, Page 34-37)
In recent years, thin-walled light-weight components are gaining increasing importance in automotive industry. Weight reduction is now a significant factor in design of new vehicles [1]. The application of aluminium alloys in the automotive industry allows to decrease the weight of automobile and achieve lower fuel consumption and CO2 emission. But it is important to consider that by reducing the weight of automotive component, its mechanical properties should remain on sufficient level. Now-a-days, most thin-walled components in automobiles are manufactured by die-casting. The application of a permanent mould casting technology for manufacturing of thin-walled castings has not been much developed. Therefore, the purpose of this study is to investigate the relation between casting parameters and mechanical properties of thin-walled light-weight components from aluminium alloys manufactured by permanent mould casting.
- August 30, 2011
Modernisation and Technology Upgradation in Foundries- Thoguluva Raghavan Vijayaram (Vol. 57, No. 7, July 2011, Page 28-33)
Foundry industry has a dominant influence on the economy of any country because metal-casting is the primary step for a large number of sub-sequential metal shaping operations. It is the basic manufacturing industry whose products are used in almost all aspects of modern industrial economy. The growth of engineering industries generally depends on the casting industry. Founding is one of the most important manufacturing processes for producing metallic engineering components. While there is a growing demand for the castings and the developed countries find it increasingly difficult to meet the demand in view of stringent environmental controls and scarcity of skilled manpower demanding better working conditions, only a few nations are ideally suited to capture a major share in world market for castings. To meet the labour requirements of the growing foundry industry, the technical training Institutes and universities offered specialised courses in this field. Universities and research organisations devoted a significant portion of their research efforts to consider the technical and allied problems in metal-casting technology. This paper discusses the needs and strategies for the technology upgradation and modernisation in metal-casting manufacturing engineering industries. Besides, the present level of foundry education and research are reviewed.
- August 30, 2011
Evaluation of Internal Closed Porosity of Aluminium Alloy Castings Through X-Ray Computer Tomography (XCT) - S. Santhi, S. B. Sakri, M. P. Subramanian, Sijo N. Lukose, D. Hanumantha Rao, C. Muralidhar and S. Sundarrajan (Vol. 57, No. 7, July 2011, Page 23
Quantification of internal closed porosity of castings has been addressed using the non-destructive evaluation (NDE). Subsurface defects are detected with radiographic inspection and it defines the qualitative amount of porosity allowed in a casting. The size, location and shape of defects were difficult with conventional film radiography. XCT is a quantitative, NDE technique for reconstructing three dimensional models of defects using CAD. Quantifying internal closed porosity in foundry industry is quite an important aspect for which XCT can provide an effective evaluation means to improve product quality. Volume of the internal closed porosity can also be quantified by titration reading of the destructive evaluation of castings. XCT analysis and its sensitivity relative to conventional film radiography and destructive evaluation of the castings of US 413 defective aluminium alloy castings have been discussed in this present study. Quantification of internal closed porosity of two defective castings was done through XCT technique and it compared well with the destructive evaluation of castings.
- August 30, 2011
Investment Casting Process Using New Ingredient in Shell Material – An Innovative Approach- D. D. Shukla, J. L. Juneja and K. Babapai (Vol. 57, No. 6, June 2011, Page 44-46)
Stainless steel grade 304 was cast by shell moulding technique using different shell ingredients. Shell formulation plays a vital role on shell strength. A well-defined shell room process and control environment can produce uniform shell with sufficient strength. From cost point of view, monitoring and control of slurry consumption are also important. Cost saving in slurry without compromising shell strength should be the goal of shell room.
- July 29, 2011
Hardness and Wear Characteristics of Al-4.5% Cu (LM11) Alloy and Fly Ash Composite (AMC)- B.N. Sarada and K. Radhakrishna (Vol. 57, No. 6, June 2011, Page 38-43)
A new class of structural materials called composite materials, have emerged as new generation engineering materials, which are gaining popularity in recent times due to some advantages they offer over conventional materials. The synergistic combination of dissimilar properties of the metal and the various combinations of reinforcement properties have propelled the use of metal matrix composite (MMC) materials into most of the engineering applications. In the present investigation, MMC was produced. Al- 4.5%Cu (LM11) alloy was used as matrix material and Fly Ash was used as the particulate in producing Aluminium metal matrix composite (AMC). Fly Ash procured from Raichur Thermal Plant was introduced into the metal by stirring the molten metal (Foundry metallurgy technique). Fly Ash percentage was varied from 5 % to15 % by weight. Cylindrical castings were produced by pouring the molten metal into preheated cast iron moulds. After solidification test, specimens were cut and machined to evaluate Microstructure, Hardness, 3-body Abrasive wear and Erosive wear. 3-body Abrasive wear and Erosive wear were carried out by allowing silica sand grains to fall on the rotating specimens. The loss in weight of the specimen at regular intervals was taken as a measure of wear. Test is carried out at various speeds. The microstructural examination revealed good uniform distribution of fly ash particles in the matrix. Hardness value increased with fly ash content. The abrasive wear and erosive wear tend to decrease with the increase in Fly ash content. The results are presented in the paper.
- July 29, 2011
Experimental Investigations and Mathematical Computations of Flame Temperature of LDO- Fired Rotary Furnace- R. K. Jain and Ranjit Singh (Vol. 57, No. 6, June 2011, Page 29-36)
The flame temperature plays an important role in melting rate, specific fuel consumption, melting time, energy consumption and emission levels of LDO-fired rotary furnace. The authors have carried out experimental investigations on flame temperature of a 200 kg rotary furnace and its effect on other parameters. The mathematical computations of flame temperature, based on different modes of heat transfer, have also been made and finally a comparison between theexperimental and theoretical results have been made.
- July 29, 2011
Development of Austempered Inoculated Low Carbon Equivalent Irons- Ajay Likhite, D. R. Peshwe and S. U. Pathak (Vol. 57, No. 6, June 2011, Page 23-28)
Inoculated low carbon equivalent irons are the high modulus cast irons. Their carbon equivalent is significantly lower than that of ductile iron. These alloys are produced by the same route as that of ductile iron. However, unlike ductile iron, the as-cast microstructure of these cast irons consists of fine graphite nodules, embedded in a pearlitic matrix, along with some amount of cementite. This cementite gets eliminated by a small duration heat treatment. The tensile strength of these cast irons can be improved by austempering treatment. However, the response of these alloys to the austempering heat treatment has remained an unexplored area. In the present investigation, effect of austempering treatment on inoculated low carbon equivalent irons (Carbon equivalents in the range of 2.6– 3.21) at 2500C and 3250C for 1 hour, 2 hours and 3 hours was studied. It was observed that the austempering treatment produces ausferritic microstructure similar to that present in ADI.
- July 29, 2011
An Investigation of Chunky Graphite Defects in SiMo Iron used for High Temperature Applications Rob Logan, Cathrine Hartung and Andy Plowman (Vol. 57, No. 5, May 2011, Page 41-48)
The demands are increasing for high temperature materials used in restrictive designs that require increased microstructural and thermal expansion stability and higher internal combustion engine operating temperatures. Furthermore, these demands have caused the industry to tighten the microstructure specifications to ensure thermal stability for cer tain applications. High silicon-molybdenum (SiMo) nodular cast irons are used extensively in exhaust manifold and turbocharger applications, due to a combination of superior resistance to oxidation and thermal fatigue as modes of failure. The current desire to increase exhaust gas temperatures can push the peak manifold temperatures above the upper limit for stability of the ferrite phase. Microstructure control and avoidance of chunky graphite is critical for ensuring that mechanical and fatigue properties are maintained at a minimum level throughout the casting. This paper is aimed to review cases of chunky graphite in nodular SiMo iron and to offer practical solutions for eliminating its presence. The presence of light rare earths (lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd)) in thick section SiMo castings produced using various MgFeSi bulk alloys and inoculants are investigated. Light rare earth levels ranging from approx. 0.01212% to 0.030% in the cast samples revealed presence of chunky graphite in iron that was relatively free of deleterious elements such as bismuth (Bi), lead (Pb), tin (Sn) and antimony (Sb). The wide range of light rare earth elements observed indicate that rare earth elements alone are probably not causing chunky graphite, but SiMo iron seems to be very sensitive to rare earth elements. For SiMo iron with section sizes upto thicknesses of 20 mm, it is recommended that the total rare earth level is kept below 0.010 % and that the base iron and final iron is well-nucleated to ensure chunky graphite is avoided.
- June 30, 2011
Simulation of a Rectangular Object with Shrinkage Defect Nandita Gupta, Manish Kant, Jena Mohan Kerketta (Vol. 57, No. 5, May 2011, Page 32-39)
Gating system design is one of the most important factors that ensure the quality of casting by controlling the mould filling pattern. In this study, the effect of gating design including gate geometry and importance of riser was investigated by pouring d
- June 30, 2011
Modelling and Optimisation of Flame Temperature in Rotary Furnace R. K. Jain and B. D. Gupta (Vol. 57, No. 5, May 2011, Page 29-31)
This paper deals with modelling and optimisation of specific fuel consumption in a LDO-fired rotary furnace, using regression analysis techniques. The authors conducted experimental investigation on fuel consumption in a rotary furnace in an industry. The regression modelling method contained in MatLab software was used for modelling and optimisation of specific fuel (energy) consumption. The percentage variation between actual experimental data and modelled results was 2.52% which is well within the permissible limits.
- June 30, 2011
Modification of a Cast Al-Si-Cu Alloy by Heat Treatment in the Semisolid State and Evaluation of Its Wear Characteristics Bhattacharya, A. K. Chakrabarti and D. K. Mondal (Vol. 57, No. 5, May 2011, Page 23-28)
Heat treatment of an as-cast Al-10Si-3.2Cu alloy in the semisolid state at 6000C resulted in rounding off of the ?-Al grains and spheroidisation of the eutectic silicon particles. A sample with the modified microstructure suffered more wear than an as-cast sample under moderate loads in pin-on-disc sliding wear test. A steady state of wear was attained when the wearing surface was work-hardened. At this stage, the coefficient of friction also dropped sharply in case of both the as-cast and semisolid heat-treated samples. SEM-ED studies indicated that wear proceeds by oxidation and delamination of the work-hardened surface. Iron (0.5%) present in the alloy as an impurity diffused into the oxide scale during the wear test denuding the work-hardened subsurface of its iron content.
- June 30, 2011
Creep Resistant Cast Magnesium Alloy Developments for Automotive Applications- B.C. Pai, U.T.S. Pillai and A. Srinivasan (Vol. 57, No. 4, April 2011, Page 35-43)
The magnesium alloys, one among the lighter structural materials finding increasingly important role in automobiles for making them lighter, fuel efficient and also environment-friendly by reducing harmful emissions. AZ91(Mg-9Al-1Zn) magnesium alloy is commonly used in automobiles because of its excellent castability, mechanical and corrosion resistance properties. However, the application of this alloy is restricted to temperatures below 120°C because of the reduction in strength and creep properties due to the poor thermal stability of the microstructure. Extensive work has been carried out to develop new thermally stable Mg alloys capable to withstand the temperature levels of 250°C for making heavier engine components (powertrain) for realising more weight reduction. Additions of alloying elements like rare earths (lanthanum, neodymium, cerium, yttrium, etc.), Si, Mn, etc. have been made to Mg alloys to improve the high temperature mechanical and creep resistance properties. Some of the developed alloys had the temperature capabilities but poor castability or corrosion resistance or sometimes become expensive because of the high cost of the alloying elements, especially with rare earths additions, discouraged their applications in automobile industries. Alternately, the existing well developed AZ91 alloy was modified by minor alloying additions to improve their high temperature withstanding capability without significantly affecting its casting, corrosion resistance and cost. This paper overviews the work carried out on the role of alloying addition on the microstructure and mechanical properties of some important magnesium alloys reported in the literature and the work being carried out by the authors at National Institute for at National Institute for Interdisciplinary Science and technology (NIIST), CSIR, Thiruvanthapuram.
- May 30, 2011
Modelling and Optimisation of Specific Fuel Consumption (with Oxygen Enriched Preheated Air) in Rotary Furnace Using Feed Forward Modelling Method of ANN- R, K. Jain, B. D. Gupta and Ayub Khan (Vol. 57, No. 4, April 2011, Page 27-34)
This paper deals with modelling and optimisation of specific fuel consumption in a LDO-fired rotary furnace using feed forward modelling method of artificial neural network (ANN). The authors conducted experimental investigations on fuel consumption in a rotary furnace in an industry. It was observed that approx. 8% oxygen enrichment of the air preheated upto 4760C simultaneously with reduction of air volume to 60% of its theoretical requirement lowered the specific fuel consumption to 0.208 lit/kg. The compact heat exchanger with 533 fins was used for preheating the air. Accordingly, the emission levels were also considerably reduced. The feed forward modelling method of artificial neural network contained in MATLAB software was used for modelling and optimisation of specific fuel consumption. The percentage variation between actual experimental data and modelled result is 1.28%, which is fairly acceptable.
- May 30, 2011
Study on Solidification Behaviour of LM6 Castings by Using Computer -Aided Simulation Software- T. Nandi, R. Behera, A. Chanda and G. Sutradhar (Vol. 57, No. 3, March 2011, Page 44-49)
Method layout of a casting is an important aspect of tooling development. It involves decisions regarding part orientation in mould, parting line, cores, cavity layout, feeders, neck and gating system. An improper method layout leads either to poor qualit
- April 29, 2011
Applying Gauge Repeatability and Reproducibility Analysis for a Cast Dimension in a Foundry – A Case Study- V. Jaiganesh, G. Sajay Surya, S. Bharath Shanker, J. Suresh Kumaar, S. Sownder (Vol. 57, No. 3, March 2011, Page 37-43)
In the current manufacturing scenario, much emphasis is placed on identifying and reducing process variation. In the shopfloor, this is achieved through a systematic application of statistical process control techniques to various process parameters. In order that the manufacturing variation is quantified correctly, it is important that the instrument/equipment used to measure the process parameter/characteristic is assessed for its inherent capability. Although the capability assessment of a measurement system involves determination of both location and variability of the measurements generated by a measurement system, in this paper, the variability assessment part of the capability studies of a measuring instrument used in a statistical process control studies in a jobbing foundry has been assessed. The inferences regarding the suitability of the measurement system has been drawn on the basis of the guidelines proposed by the Automotive Industry Action Group (AIAG).
- April 29, 2011
Effect of Refractory Brick Lining on Fuel (Energy) Consumption, Heat Losses, and Life of LDO-Fired Rotary Furnace- R. K. Jain, S. K. Bajpai and B. D. Gupta(Vol. 57, No. 3, March 2011, Page 31-36)
A series of experimental investigations were conducted on a LDO-fired rotary furnace of 200 kg capacity installed at S. Harbhajan Singh, Namdhari Enterprises Industrial Estate, Nunhai, Agra for production of cylinder heads and auto parts, and at Faculty of Engineering, Dayalbagh Educational Institute (DEI), Dayalbagh, Agra. These experimental investigations on the rotary furnaces produced excellent results which are accrued here.
- April 29, 2011
Mechanism of In-situ Reinforcement Formation in Fabrication of AA6061-TiB2 Metal Matrix Composite- A. Mahamani(Vol. 57, No. 3, March 2011, Page 27-30)
Aluminium matrix composites are attracting many researchers due to its superior properties like high specific modulus, stiffness, hardness, wear resistance and strength. However, the mechanical properties of the aluminium alloy are adversely affected by the presence of the coarse reinforcement particle, microstructural heterogeneity and a non-uniform distribution of particles. The composites synthesised using the in-situ techniques can eliminate these limitations. Fine and small-size particle entrapment in the matrix–reinforcement interface helps in the formation of stronger interfacial bond. TiB2 is a refractory compound that exhibits high melting point, hardness, modulus and elevated strength. Flux-assisted synthesis is an economic method to produce the Al-TiB2 in-situ composite. However, the commercial application of this composite requires lot of understanding on the mechanism of in-situ reaction. An attempt has been made to investigate the mechanism of in-situ reaction in production of AA6061-TiB2 metal matrix composite.
- April 29, 2011
Modification of Al-Si Alloys by Heat Treatment - A. K. Chakrabarti and D. K. Mondal(Vol. 57, No. 2, February 2011, Page 41-44)
Modification of eutectic silicon in a hypoeutectic Al–5Si alloy and a hypereutectic Al–15Si alloy has been attempted by isothermal heat treatment at 5600C (below eutectic temperature) and 6000C (above eutectic temperature). Isothermal heat treatment at 5600C resulted in fragmentation, spheroidisation and clustering of silicon particles in both the alloys. Isothermal treatment at 6000C resulted in globularisation of the ?–Al phase in Al–5Si alloy and modification of only eutectic silicon in Al–15Si alloy.
- March 31, 2011
Transforming SMEs Through Lean Manufacturing Clusters - Sumit Roy (Vol. 57, No. 2, February 2011, Page 35-40)
Ministry of MSME proposed to form 100 mini-clusters all over the country with the objective of enhancing manufacturing competitiveness among MSMEs through application of lean manufacturing techniques. The timeframe of implementation was stated to be one year. One among the first such clusters was awarded to the author. The cluster was formed at Pune under the auspices of MCCIA, Pune. In view of author’s several years’ of experience in managing clusters of medium and large enterprises, the assignment initially appeared to be repetition of the conventional model star ting with Five S, Quality, Inventory Management, Productivity Improvement, etc. ending with Value Stream Mapping (VSM). However, the background of these SMEs, time-frame of one year and certain glaring gaps in these companies are required for complete redesigning of the lean implementation model. In view of the gaps in data management, competency of personnel, absence of certain basic systems, poor employee participation in managing quality, etc. made the task even more challenging. The approach had to be more hand-held and shopfloor-oriented rather than classroom focused to make the implementation effective and visible. At the end of the first eight months’ implementation, the results are strikingly different in terms of performance measures and physical shop-floor changes. This paper attempts to document a structured approach to overcome practical difficulties in implementing basics of lean management practices in Indian SMEs.
- March 31, 2011
Correlating Fracture Toughness and Texture in Cast and Annealed Al-6Mg Alloy with Minor Additions of Scandium and Zirconium - M. Ghosh, R. Sen and M. K. Banerjee (Vol. 57, No. 2, February 2011, Page 31-34)
Deformation of Al-Mg alloys is suitable for structural applications where corrosion resistance is important. The effect of trace addition of scandium and zirconium has been investigated by using XRD and transmission electron microscopy. Texture and fracture toughness of Al-Mg-Sc and Al-Mg-Sc-Zr alloys of varying compositions annealed at 300°C were investigated. It has been found that scandium modifies the microstructure of Al-Mg alloy and considerably improves the fracture toughness property of the alloy at the temperature of interest when deformation becomes homogeneous due to coarsening of Al3Sc precipitates. Addition of Zr increases the fracture toughness value even further.
- March 31, 2011
Realisation of Lightweight Machine Tool Components by Modern Foundry Technology - K. Gnanamurthy (Vol. 57, No. 2, February 2011, Page 23-30)
Several Machine tool components are cast metals made in Foundries. They are generally of grey cast iron with some alloying, and in some cases Spheroidal Graphitic iron. Historically, machine tools like any other machine might have been fabricated in steel with a number of cross-ribs for stiffness, and eventually the foundries were asked to duplicate the prototype in Iron. Now, in order to optimise weight of components, it is important to re-evaluate the design inputs in terms of the various static and dynamic loads, and simultaneously work with foundries and review the characteristics of cast metals in terms of their strength, yield, ductility, hardness, wear resistance, fatigue properties, castability, reliability of foundry process etc. The paper reviews a range of metals including metal foams and recommends a structured concurrent engineering process between foundryman and designer to realise lightweight cast components.
- March 31, 2011
Minimising the Casting Defect Using Casting Simulation –A Case Study of an Industrial Casting - K. K. Singh and Rajni Ranjan Mishra (Vol. 57, No. 1, January 2011, Page 49-54)
Casting is important for engineering application and it is the backbone of automobile and other engineering sectors. It is utmost important to have the quality casting with minimum weight, soundness and good surface finish. Reduction in a small percentage rejection, can save lot of energy in a foundry and can make it competitive in the global market. Still many foundries use the approach of trial and error method in shop-floor to reduce the casting defect by wasting lot of time and energy and still not able to achieve thatlevel of casting yield and soundness. A casting design and simulation approach was taken to minimise the defect in an industrial casting by controlling the thermal gradient, pouring temperature and modification in gating design. It was found that hot spot observed in bracket area of casting where shrinkage was leading. By analysing the shop-floor data it was found that the die temperature was slightly lesser than the desired value. The simulation results were compared with the industrial results to demonstrate the accuracy of the proposed thermal and fluid flow simulation approach. It was found that a good agreement exists between the two sets of results. Various experiments were done by increasing the metal temperature and die temperature to get the proper range of die and metal temperature on which die will work properly and sound casting will come out. This concept was implemented in reality and the rejection rate was reduced from more than 13% to approximately 3.0%.
- February 28, 2011
A Study on Fluidity and Hot-Tearing of A206, A518 and A713 Cast Alloys- Anil. K. Birru, M. M. Mahapatra, D. B. Karunakar and Pradeep Kumar (Vol. 57, No. 1, January 2011, Page 38-45)
Fluidity of molten metal is of significant importance in producing sound thin-walled castings. Hence, one of the primary factors to be taken into account during the foundry practices of thin sections is fluidity of the material. The aim of the present investigation is to study the influence of pouring temperatures on the fluidity of A206, A518 and A713 alloys. The spiral tests of these alloys were conducted for temperatures at 680OC, 715OC, and 780OC. Hot-tearing tests were also conducted to determine the effect of pouring temperature on crack length. The spiral test results were compared with the results obtained by other investigators. The spiral test results exhibit an approx. similar increment, as those of the other researchers, of fluidity for A206, A195 alloys, A713, A40E alloys and for A518, A220 alloys. The percentage increase in the fluidity shows similar results, as those of the other researchers, for these alloys at minimum pouring temperature. Similarly, hot tearing test results of A713 alloys indicate that the alloy is prone to hot tearing which approx. is three times when compared to hot tearing of A206 alloy. For A518 alloy, no hot tears were found out under the same pouring conditions.
- February 28, 2011
Developments in Magnesium Alloys for Transport Applications – An Overview - Arun Boby, U.T.S Pillai and B.C. Pai (Vol. 57, No. 1, January 2011, Page 29-37)
Magnesium, being a lightweight and having high specific strength and modulus is an attractive structural material for automobile manufacture to replace steel, cast iron and even aluminium- based alloys in many components to make the transport vehicle lighter. The need for fuel economy and demand for reduced levels of emissions stipulates the need to reduce the weight of automotive components. This paper gives an overview of the advantages, limitations and applications of Mg alloys in the automotive industry. The current status on research and development of magnesium alloys and recycling of Mg alloys are summarised.
- February 28, 2011
Scrap Polymer as a Partial Replacement of Graphite for Cast Iron Production - Sudip K. Samanta, H. Roy, D. P. Chattopadhyay, S. Kumar, S. S. Roy, A. K. Chowdhury and S. Majumder (Vol. 57, No. 1, January 2011, Page 23-28)
Plastics are being used extensively in almost every aspects of our daily life. But disposal of plastics creates a lot of problem because most of the plastics are not bio-degradable; as a result, they threaten pollution hazards to environment. For effective disposal of plastic material and economic use of the same, this paper investigates the feasibility of using scrap polymer/ plastics as the alternative materials for carbon required during production of cast iron. This will not only help us to properly dispose of the polymer/ plastics but also lower the production cost of cast iron. Several melts were taken using Medium Frequency Induction Melting Furnace and by charging steel scrap, foundry return, ferrosilicon along with polymer. Chemical analysis, mechanical properties and microstructural characteristics of the melts were studied extensively. It has been seen that there is considerable amount of carbon pickup from the polyethylene addition during melting. Results of the mechanical properties evaluated from the melts were compared with those of cast iron produced by graphite addition and found satisfactory. Microstructural characteristics were also studied which depicts normal ferrite-pearlite structure along with graphite flakes. The present study shows that the scrap plastics/polymers can be used as a source of carbon during production of cast iron.
- February 28, 2011
Investigation of Intermixing with the Use of Flow Modifiers in a Two-Strand Slab Caster Tundish - Suman Kant, P. K. Jha and Pradeep Kumar (Vol. 56, No. 12, December 2010, Page 39-45)
Ladle changeover during sequential casting process gives rise to intermixed grade steel in continuous casting tundish steelmaking process. With an aim to minimise the intermixed grade steel, flow modifiers were used in the bare tundish. Experimental investigation of the intermixing process was first carried out on bare tundish to validate with the numerically obtained results where the concentration of new grade steel is monitored at the outlet of the tundish in case of old ladle carrying old grade steel being replaced by new ladle with new grade steel. A close match was found between the experimental and numerically obtained results. The study was extended numerically to study the effect of flow modifiers like dam, turbo-stop and combination of dam and turbo stop on the intermixed amount in tundish. It was found that placement of dam before outlet resulted into decrease in the intermixed amount whereas placement of turbo stop at the bottom of the tundish below the inlet resulted in increase in the intermixed amount. When dam and turbo stop both were used in the tundish, the result was seen to be better than that by the dam. Three different heights of the turbostop and two different heights of dam were used in combination. It was found that height of the dams or turbo stop did not affect the intermixed amount significantly. Larger heights, however, produced slightly better results by producing less intermixed amount.
- January 31, 2011
Oxide Scale Characteristics in a High Silicon Cast Iron - Aniket Thakur, Sujit K. Gupta, Ankit Singhania, D.K. Mondal and A. K. Chakrabarti (Vol. 56, No. 12, December 2010, Page 36-38)
The microstructure, morphology and analysis of the oxide scale formed on a 14.0% Si cast iron in both as-cast and heat-treated condition has been investigated. In as-cast condition, the average Fe2O3 content in the oxide scale in transverse section is higher than the Fe2O3 content on the outer surface of an oxide nodule. After heat treatment at 9000C, both perfect and exploded outcrops of oxides are visible on the scale surface. While the perfect outcrops are rich in carbon, the exploded outcrops are denuded of carbon and are rich in rare earth oxides.
- January 31, 2011
Recent Developments in Cupola Melting - R. K. Jain and B. D. Gupta (Vol. 56, No. 12, December 2010, Page 31-35)
Almost all the foundries use coke-fired cupolas for melting. The voluminous production of flue gases by cast iron foundries using coke-fired cupolas damage the environment, since it contains harmful gases like SO2, CO2, CO and H2S which are poisonous to all living beings. Sometimes, the melting practice by coke-fired cupolas does not obey the environmental regulations. Not only the environmental problems but energy consumption is also much higher. In view of diminishing natural resources of energy, consumption of oil, coal, gases etc. required to be drastically reduced. Several industrial organisations have made certain developments in cupola melting by installing pollution control devices and introducing energy saving techniques. This paper presents the details of developments in cupola melting.
- January 31, 2011
Investigation of the Effect of Chill Surface Roughness,Coating and Location on Heat Transfer During Solidification of Modified Al-Si Alloys - Sathyapal Hegde and K. Narayan Prabhu (Vol. 56, No. 12, December 2010, Page 23-30)
In the present work, the effect of chill parameters on heat transfer during solidification of Al-Si alloys is investigated. Modified alloys exhibited higher heat flux transients on coated chills due to improved wetting. Wetting behavior of the coating material had a significant effect on the estimated heat flux. Roughness of the chill had significant effect on heat flux transients particularly for unmodified alloys. Heat flux transients were lower for top chilled castings due to the absence of gravity effect. The peak heat flux obtained with bottom chilled castings is nearly three times compared to top chill experiments.
- January 31, 2011
Short-Term Decision Making in Foundry Unit: A Case Study - Devendra Choudhary and P. K. Jain (Vol. 56, No. 11, November 2010, Page 34-39)
Break-Even-Point (BEP) analysis and Incremental Analysis (IA) are important techniques which are widely used for short-term planning purposes. BEP seeks to examine the relationship between costs, volume, sales and profit. IA is a useful managerial tool in a variety of situations, including evaluating pricing strategy, determining special order/booking acceptance or choice of sales mix. This study examines the basic BEP and IA model and describes how to make use of information provided by them in the decision-making process in foundry industry. For this, we gathered various cost data from a recently started foundry unit in Ajmer which casts sewing machine table stands. Further, we segregated these data into fixed costs, mixed costs and variable costs. Therefore, the purpose of this case study is to show how to segregate different cost data into fixed and variable costs and perform BEP and IA analysis.During this study, it was observed that many owners of small foundry units in India are very sincere and hard-working, but they do not have any formal education in engineering and finance. It is hoped that this case study will help SME foundry unit owners in short-term decision making.
- December 29, 2010
Effect of Flame Temperature on Fuel (Energy) Consumption, Melting Time and Melting Rate of LDO-Fired Rotary Furnace - R. K. Jainand B. D. Gupta (Vol. 56, No. 11, November 2010, Page 23-29)
Furnace used for production in ferrous foundries. The extensive experimental investigations were carried out on a 200 kg LDO-fired rotary furnace installed at a foundry shop in Agra and revealed that flame temperature is an important parameter which affects not only the energy consumption but also the performance of rotary furnace.
- December 29, 2010
Effect of Lead Addition in LM6 Alloy Castings- Thoguluva Raghavan Vijayaram and S. Thiru Chitrambalam (Vol. 56, No. 10, October 2010, Page 38-42)
In this research work, lead is added in the LM6 alloy melt and casting samples in the form of a slab are made by pouring the treated alloy in the sand moulds. Lead is added in the range from 2% to 14% in the chosen LM6 alloy. The chosen pouring temperature was around 800 degree centigrade. In this work, effect of lead on the hardness, microstructure and impact strength are discussed. Besides, corrosion resistance tests are conducted and the results are discussed. Fracture surface studies are also conducted on the samples after the impact test and fractographs are captured to analyse the type of failure.
- November 30, 2010
Study of Carbides in Austenitic Stainless Steel- Aniruddha A. Gadhikar, C. P. Sharma, D. B. Goel, Ashok Sharma and S. K. Goel (Vol. 56, No. 10, October 2010, Page 23-28)
Presence of carbides in the microstructure of alloy steel plays an important role in the end properties and hence enhances the suitability of the steel for various applications. Though carbides, in general, improve resistance of austenitic stainless steel to heat and abrasive wear, they are considered to be detrimental to fatigue, erosion and corrosion resistance of the steels. In this paper, general study of carbides in austenitic stainless steel is presented.
- November 30, 2010
Effect of Core Materials on Solidification Time and Pattern in Steel Castings- S. P. Bulusu, N. Seetharamu and T. Sundararajan (Vol. 56, No. 9, September 2010, Page 36-40)
Castings are often required to have holes and recesses of various sizes and shapes. These impressions in castings can be obtained by using cores. In the present work, a numerical study of heat transfer during the solidification of steel casting with core has been presented. A conjugate conduction based finite element heat transfer analysis of metal, mould and core with interfacial air gap has been performed. The heat transfer through the air gap has been modelled using the coincident node technique. Effect of core materials on solidification times and patterns of square shaped steel castings has been studied. The solidification time and sequence of solidification pattern is different when zircon is used as core material in comparison to silica.
- October 29, 2010
A Case Study on Modelling and Optimisation of Specific Fuel Consumption in Rotary Furnace- R. K. Jain, B. D. Gupta and Ranjit Singh (Vol. 56, No. 9, September 2010, Page 33-35)
This paper deals with modelling and optimisation of specific fuel consumption in a LDO-fired rotary furnace, using regression analysis techniques. The authors conducted experimental investigation on fuel consumption in a rotary furnace in an industry. It was observed that 6% oxygen enrichment of the air preheated upto 460º C simultaneously with reduction of the air volume to 75% of its theoretical requirement lowered the specific fuel consumption, and reduced the emission level. The performance of the furnace was also considerably improved. The regression modelling method contained in MatLab software was used for modeling and optimization of specific fuel (energy) consumption. The percentage variation between actual experimental data and modelled results was 12.35% which is well within the permissible limits.
- October 29, 2010
A New Economical Method for Development of Gunmetal Foam Castings- S. Sridhar, S. S. Mohamed Nazirudeen and M. Kavitha (Vol. 56, No. 9, September 2010, Page 29-32)
In recent years, there is a high demand for the development of metal foams. The interesting properties of these metal foams are: good energy absorption, low thermal conductivity, recyclability etc. A new process has been developed with the goal to achieve materials having good property to cost ratio. They can be used in structural applications owing to their excellent durability and strength-to-density ratio. This paper deals with the special interest in formation of porosity in gunmetal castings. This also illustrates the experimental work done to investigate the possibility of forming porous structures and the inspection methods to confirm the pores formed in and all through the produced castings. The density and percentage porosity of the produced castings were analysed and presented.
- October 29, 2010
Compacted Graphite Iron for Non-Automobile Industry- Subrata Chakrabartti (Vol. 56, No. 9, September 2010, Page 23-28)
While castability of CGI is as good as grey iron or ductile iron, its fatigue resistance property is far superior to aluminium and grey iron. With better and consistent technology of production, CGI is the recent craze of automobile engineers.
- October 29, 2010
Ductile Iron Railway Sleepers and Their Properties Compared to Steel Sleepers- P. Srinivasa Rao, S. K. Sengupta and P. K. Mohanty (Vol. 56, No. 8, August 2010, Page 45-53)
The paper describes briefly the results obtained from a total number of 12 comparative static and dynamic load tests on the presently used steel railway sleepers (broad gauge) and newly developed equivalent sleeper substitutes out of ductile iron developed by M/s, Tor Isteg Steel Corporation. The ductile iron sleepers have not only the advantage of extremely improved corrosion resistance as against steel sleepers but offer also the added advantage of some of the possibility of casting some of the rail fastening devices integrally with the sleeper. The results of the tests conducted so far indicate that the ductile iron used in the trial sleeper castings possessed static tensile strength comparable to that of steel and satisfied very closely the minimum static strength requirements specified by the Railways for the basic steel material. The static bending moment capacity of the rail seat section of the ductile iron sleeper was very much superior to that of the steel sleeper. The percentage elongation arid the fatigue strength behavior of the ductile iron sleeper were however inferior to that of the steel sleeper. This is believed to be largely due to the relatively high phosphorus content in the trial casting material and can be improved by suitably altering the composition. It has been shown that it is possible to improve further the behaviour of the ductile iron sleepers also by readjusting the cross-sectional characteristic in an optimum fashion.
- September 30, 2010
Corrosion Resistance Property of Graded Austempered Ductile Iron- Shampa Dhar, Malay Kumar Roy Choudhury, A. K. Chowdhury and P. K. Mitra (Vol. 56, No. 8, August 2010, Page 42-44)
Austempered Ductile iron (ADI) is produced by isothermal treatment of Mn, Ni, Cu and Mo. Austempering treatment provides ADI with excellent combination of strength, toughness and resistance characteristics. ADI is presently used in the following sectors, viz., Agricultural equipment, Construction equipment, Gears/Power-trains, Heavy Truck/Trailers, Light vehicles/buses, Mining/Forestry equipment, Railway, Farm/Oilfield machinery, Conveyor equipment and Sporting goods. Evidently majority of the components are subjected to varied corrosive environments. ADI are available in five grades, ASTM grade I to ASTM grade V. In the present work, corrosion resistance property of ASTM grades I to III have been measured in NACE solution. All the grades exhibit comparable and reasonably good corrosion resistance property. However, results of ASTM grade III ADI samples show least scatter and reasonably good passivity.
- September 30, 2010
Casting Process Development – A Systematic Review of Principles Involved: Part II - V. Jaiganesh (Vol. 56, No. 8, August 2010, Page 35-41)
This paper, the second in the series of three, explains in detail the methodology of Failure Modes and Effect Analysis for a casting process although the approach could be adopted for any process. Although a generic procedure for FMEA is already available, there are a number of elements in FMEA that are not properly understood in terms of their implications, by the foundry engineers. Many a times it is found that FMEA for a component casting or process is carried out as a mere ritual without any meaning. This is unfortunate as the process and hence the product reliability very much depends on the grass root level understanding of the intricacies of the process. Although this understanding depends entirely on the domain knowledge, the framework of process FMEA helps to put this knowledge in a systematic and coherent way that highlights the critical features of the process needing attention and constant monitoring and control which ultimately brings about improved process reliability. In view of the fact that many foundries are supplying castings to automotive OEM manufacturers, it has become essential that they improve the reliability of their processes for their survival in the competitive market.
- September 30, 2010
Studies on Mould Filling Ability of US 413 and US A356 Cast Aluminium Alloys- S. Santhi, S. B. Sakri, D. Hanumantha Rao and S. Sundarrajan (Vol. 56, No. 8, August 2010, Page 28-34)
Mould filling is the most important aspect in the casting process. It influences considerably the heat transfer and solidification of the melt. Mould filling is a critical stage in the production of sound and quality castings, especially in the case of complex shaped castings section thickness varies considerably. The mould filling ability of aluminium alloys US 413 AND US A356 has been studied in the present investigation. Necessary experimentation is carried out using orthogonal array experimental layout. The process parameters studied in the present investigation are alloy composition, sand fineness, mould coating and pouring temperature. The mould filling ability is studied using pin test piece with cylindrical cores. The results from experimentation are analysed to find the influence of the process parameters on mould filling ability.
- September 30, 2010
Rheocasting and Thixocasting: Semi-Solid Casting Technologies- Thoguluva Raghavan Vijayaram Vol. 56, No. 8, August 2010, Page 23-27)
The new trend in the automotive industry and aerospace industry to produce more fuel-efficient automotive vehicles and lightweight engineering components has resulted in the increased use of aluminium and magnesium alloys. Currently, high-pressure die-casting process fulfils the bulk requirement of the automotive industry as well as aerospace industry needs. However, the increasing demands on quality and weight reduction have driven the development of new casting processing technologies. The problems associated with liquid metal high-pressure die-casting have resulted in the increased interest in semi-solid forming processes. Such processes are rheocasting and thixoforming technologies. Rheocasting and thixocasting are potential semi-solid casting techniques. Both are potential foundry processes capable to manufacture lightweight aluminium and magnesium alloy castings. In this article, various aspects on rheocasting technology and thixoforming process are discussed in a simplified manner.
- September 30, 2010
The New Method for Fast Testing of Surface Tension of Liquid Alloy and Its Application in Foundry Production - LI Da-Yong, SHI De-Quan and WANG Li-Hua (Vol. 56, No. 7, July 2010, Page 40-45)
Surface tension of liquid alloy relates to solidification of liquid alloy, inoculation and refining effect. In order to fast evaluate the quality of liquid alloy by surface tension, a new method and a new device for fast testing of surface tension have been developed by authors. In the paper, the principle of the new method and device and their application in graphite shape identification of cast iron and inoculation effect evaluation of aluminium alloy were introduced.
- August 31, 2010
Some Critical Aspects of Solidification and Grain Refinement of Aluminium Alloys- Divya Kohli, Ajay Pareek and Ashok Sharma (Vol. 56, No. 7, July 2010, Page 31-39)
Aluminium and its alloys usually exhibit a coarse columnar grain structure unless treated for grain refinement prior to solidification. The coarse columnar grain structure not only affects the mechanical properties and machinability adversely, but also leads to poor castability and microporosity due to the coarse dendritic solidification. However, treatment of the molten Al for grain refinement prior to casting ensures that the same solidifies to a fine equiaxed grain structure instead of the usual coarse columnar one. Currently, different binary and ternary grain refiners are in existence, the grain refiner master alloys used in grain refinement of aluminium and its alloys include Al-Ti, Al-Ti-B, Al-TiB2, Al-B and new generation of Al-Ti-C master alloys. The heterogeneous nucleating particles responsible for grain refinement are TiAl3, (TiAl3+TiB2), TiB2, AlB2 , (TiB2+AlB2), TiC and (TiC+ TiAl3). Fundamentals of solidification, grain refiners synthesis, mechanism and other various aspects of grain refinement are critically discussed.
- August 31, 2010
Synthesis and Characterisation of Al 6061-5%Cu Composite Reinforced with In-Situ TiB2 and ZrB2 Particles - A. Mahamani (Vol. 56, No. 7, July 2010, Page 23-30)
Al-6061 -5 % Cu –TiB2/ZrB2 in-situ metal matrix composite has been fabricated by mixed salt reaction. During the synthesis, mixed salts of potassium hexafluorotitanate (K2TiF6), potassium hexafluorozirconzte (K2ZrF6) and potassium tetrafluoborate (KBF4) are introduced into a stirred copper-aluminium melt at 850 0C. The reaction holding time was maintained upto 5 minutes. The formation of TiB2 and ZrB2 reinforcements are by exothermic reaction. Basic microstructural studies using XRD, EDAX and SEM were carried out to validate the presence of reinforcement in the casting. An attempt has been made to investigate effect of copper in the Al-6061–TiB2/ZrB2 in-situ metal matrix composite on structural, microstructural characteristics and hardness. The microstructure shows the presence of TiB2, ZrB2, formation of CuAl2 in the grain boundaries and there is no detectable interface interaction between component grains. XRD test was also carried out in the specimen and the presence of TiB2, ZrB2 and CuAl2 particles was confirmed using the peak charts. The contributions of elements in the composites are quantified by EDAX analysis. The micro-hardness analysis indicates that the presence of copper and in-situ reinforcements in aluminium matrix increases the hardness. This microstructural characterisation of Al MMCs is very useful for carrying out further studies on mechanical, weldability and machinability.
- August 31, 2010
Casting Weight Optimisation - Purshottam K. Godhia (Vol. 56, No. 6, June 2010, Page 43-45)
The need of the day is to reduce cost of components by reducing input / final weight of components. Here, Grey & Nodular Iron casting components are considered.
- July 29, 2010
Development of Wear-Resistant Austempered Ductile Iron Hammers for Ore Crushing Application :: A Case Study - A. K. Chowdhury, S. K. Samanta, D. P. Chattopadhyay, S. Kumar, T. Ray and S. Sinha Roy (Vol. 56, No. 6, June 2010, Page 39-42)
Austempering is a special type of heat treatment process which when applied to ferrous materials produces a unique matrix that have special mechanical properties compared to those processed by conventional methods. ADI and Carbidic Austemered Ductile Iron (CADI) materials are very much suited for hammer applications due to its increased wear resistance and high strengthto- weight ratio. Component like reversible hammers made of Mn steel used in crushing mills application can be best replaced by ADI and CADI material due to increased wear resistance properties as well as tough matrix. In the present investigation, hammers were developed with wear-resistant ADI and CADI material to enhance the life of the components for reversible hammer mills of iron ore crushing line. Solidification simulation using AFS software was used to optimize the process parameter for the casting of the component right at the first time. The software enables us to optimise the exact location and proper dimension of feeding system considering quality and yield. Performance evaluation of the developed component was carried out which showed that around 1.5 times life can be enhanced compared to that of existing SHRI hammer made of steel.
- July 29, 2010
Indian Ferrous Foundries :: An Overview - R. K. Jain and B.D.Gupta (Vol. 56, No. 6, June 2010, Page 34-38)
The foundry industry is a core industry producing castings which is a basic raw material to all sectors. Our country is now the 4th largest producer of ferrous and non-ferrous castings in the world. The present state of affairs of Indian ferrous foundries is not encouraging. Besides, several general problems, certain specific problems viz stringent pollution control norms of CPCB and energy consumption norms of TERI are to be strictly followed. Recently by orders of Hon’ble Supreme Court of India approximately 396 foundries in TTZ (Taj Trapezium Zone) region have been closed down. Further, impact of globalisation is also an important factor. The authors have conducted a deep survey of leading foundries and have submitted an overview of Indian ferrous foundries. Under present circumstances, “An Eco-friendly and Energy-Efficient Furnace for Ferrous Foundries” is required.
- July 29, 2010
Heat Treatment of Lead Castings - Thoguluva Raghavan Vijayaram (Vol. 56, No. 6, June 2010, Page 29-33)
This research paper focuses on lead casting processing, heat treatment operations on the lead metal castings and analysis of mechanical properties and microstructural characterisation. The basic sand casting method is adopted to process the lead castings. Three methods of heat treatment are performed on the processed lead castings, viz., common quenching, annealing and normalising operations. Hardness, tensile strength is determined and microstructural analysis is performed on the heat-treated lead castings. The effects of the mechanical properties and microstructure for different types of heat treatment on lead castings are discussed in this paper.
- July 29, 2010
Evaluation of Wear Properties of Al-Graphite Metal Matrix Composite Produced Through Stir Casting - M. Ramachandra and K. Radhakrishna (Vol. 56, No. 6, June 2010, Page 23-28)
The paper presents the results of experimental investigation on mechanical properties, machinability and forgeability of silicon carbide particle (SiCp) reinforced aluminium alloy i.e. LM6 metal matrix composite. The influence of reinforced ratios of 5 and10wt.% of SiCp on mechanical properties and forgeability was examined. The effect of machining parameters, e.g. cutting speed and depth of cut on surface roughness and cutting forces at constant feed rate was studied. It was observed that increase of reinforcement element addition produced better mechanical property like hardness and the forgeability of cast MMCs decreases. Machinability properties of the cast material were studied and it was noted that higher SiCp reinforcement produced a higher surface roughness. It was observed that the surface roughness and cutting forces were affected by the depth of cut and cutting speed at constant feed rate.
- July 29, 2010
An Experimental Study on the Effect of Silicon Carbide Particulates (SiCp) on the Mechanical Properties Like Machinability and Forgeability of Stir-Cast Aluminium Alloy Metal Matrix Composites - Rabindra Behera, A. Dutta, Sujit Das, Kiriti Majumdar, D. Ch
The paper presents the results of experimental investigation on mechanical properties, machinability and forgeability of silicon carbide particle (SiCp) reinforced aluminium alloy i.e. LM6 metal matrix composite. The influence of reinforced ratios of 5 and10wt.% of SiCp on mechanical properties and forgeability was examined. The effect of machining parameters, e.g. cutting speed and depth of cut on surface roughness and cutting forces at constant feed rate was studied. It was observed that increase of reinforcement element addition produced better mechanical property like hardness and the forgeability of cast MMCs decreases. Machinability properties of the cast material were studied and it was noted that higher SiCp reinforcement produced a higher surface roughness. It was observed that the surface roughness and cutting forces were affected by the depth of cut and cutting speed at constant feed rate.
- June 30, 2010
Casting Process Development – A Systematic Review of Principles Involved : Part I - P. Sindhiya, K. R. Vignesh and V. Jaiganesh (Vol. 56, No. 5, May 2010, Page 35-42)
This paper in three parts attempts to explain systematically the principles involved in the development of a suitable process route for a cast component. Although the procedure is a part of new product development, much emphasis is now being laid by foundries towards a better understanding of the variables involved in the manufacture of castings as well as preventing rejections/process failures. Although the procedure for new product development is foundry specific that is already available, there are a number of elements that are not properly understood in terms of their implications by the foundry personnel. In view of the fact that many foundries are supplying castings to automotive OEM manufacturers, it has become essential that they improve the reliability of processes for their survival in the competitive market. In this context, a thorough understanding of the various elements of process development and their significance cannot be overemphasised, if the potential of the underlying principles is to be fully exploitedand the objectives of the organisation realised. Also the methodology reviewed in this paper is a part of the mandatory requirement called Advanced Product Quality Planning (APQP) by ISO/TS 16949 Quality Management System.
- June 30, 2010
Meeting Customer Expectations – PPAP - Prashant Mestry (Vol. 56, No. 5, May 2010, Page 30-34)
During casting development process with casting suppliers, it is often observed that the foundries do not follow Production Part Approval Process (PPAP) religiously. During initial sampling problems do not get exposed, but as soon as one goes for bigger volumes or ramp-up production, problems multiply. Small defects which occur during initial stage are not attended or not given much attention. This kind of problems create hurdles during rampup. This happens due to improper product development process. During the initial stage production requirement is less and foundries compensate the defectives by producing extra quantity. At Mahindra and Mahindra, it is expected that detailed analysis of the defective castings be carried out so that during ram-up production difficulties become less. Procedures related to PPAP are required to be strengthened at the end of the Casting suppliers which include documentation related to Advanced Product Quality Planning (APQP), Control Plan, Failure Mode Effect Analysis (FMEA), Process Flow Diagram, etc. In order to make PPAP stage more productive from the stand point of both Mahindra and Mahindra as well as casting suppliers, it is felt that stricter adherence to PPAP methodology would bring better results during product development. This would reduce time spent at both Mahindra and Mahindra and at the suppliers end. This paper attempts to clarify PPAP process and also discusses methodology to address specific gaps that are normally faced during product development process at the end of casting suppliers.
- June 30, 2010
Managing Foundry Supply Chains - Brijesh Ainapur and P. R. Vittal (Vol. 56, No. 5, May 2010, Page 25-29)
Over recent years supply chain management has grown in importance because of the improved information flows, outsourcing practices, strategic alliances and partnerships and the reshaping of the organisational focus from functional silos toward integrated activities. India is the fourth largest producer of castings in the world. But, the emphasis on this industry is very less when compared to other industries like steel, coal, petroleum etc. Even many people felt that foundry will be the last option for their career. But the joy of working in foundries only foundryman can feel and express. There are endless opportunities to grow and improve the system. Lot of technological up-gradation has taken place in the foundry industry, starting with manual moulding changed to ARPA moulding machines and now with high pressure moulding lines capable of producing 120 moulds per hour with box and 360 moulds per hour with boxless moulds. But, there is no or little evidence that has taken place in managerial decision making and importance to entire supply chain as a whole. Every time decisions are taken only to upgrade plant facilities without looking into supply chain partners, which will end up either with scarcity of raw materials or excess of finished goods. Most of the supply chain networks fail to succeed, because either they fail to measure the right KPI (Key Performance Indicator) or due to not knowing how to proceed with the measured KPI’s. Many feel that, continuous improvement in an organisation relies on “measuring, measuring and measuring again”. What’s next after measuring? Effective supply chain design calls for robust analytical models and design tools. This paper presents a systematic way for KPI - Identifying, Measuring, Benchmarking, finding the limiting constraint and attacking the constraint using Analytical Hierarchy Process (AHP) in foundries. Supply Chain Council (SCC) guidelines are used for identifying and measuring the KPI’s using SCOR level 1 metrics.
- June 30, 2010
Enhancing Competitiveness of Small and Medium-Size Foundries : Scope, Challenges and Way Forward - Mukesh Gulati, Neetu Goel and N. Ramamurthi (Vol. 56, No. 4, April 2010, Page 44-52)
There are over 4500 registered foundry units in India. Of these, about 3,000 units are grey iron foundries. Of the total tonnage of 5.1 million tonnes of grey iron castings produced in our country, nearly 60% is through Cold Blast Cupola route. This accounts for about 3.0 million tonnes. In addition, another 1.0 million tonnes is produced by units which are not registered. The baseline study of 80 foundries in Haryana indicated that there is a large potential for saving 10-35% of coke consumed by improving cupola operation, and in some cases by changing over to Divided Blast Operation. This would be a huge saving in coke by any reckoning and would also lead to substantial improvement in pollution levels. It was found that some intervention had been done by Government Agencies, Funding Institutions and Organisations specialised in Energy improvement. However, not more than 100 foundries have so far benefitted from this effort. It was felt that the Cluster Development Approach would be appropriate to ensure wider benefit to a large number’of foundries. A small industrial town of Samalkha, about 80 km from Delhi, was chosen as a test case. The details of diagnostic study, methods adopted for developmentand sustenance of the cluster, improvements effected in operation of the cupolas and resultant savings in coke are presented in this study. It is felt that this methodology can be replicated in other foundry clusters to the benefit of small and medium-size foundries all over the country. Joint action by private funding Institutions, Industry Institutions like The Institute of Indian Foundrymen and the Government would go a long way in realising this objective.
- May 31, 2010
Precipitation Studies and Properties of Cu-Fe-Zr-B Alloy - M. S. Raviraj & A. O. Surendranathan (Vol. 56, No. 4, April 2010, Page 38-43)
The Cu-Fe-Zr-B alloy was produced by melting the master alloys Cu-Zr (11% Zr) and FeB (15% B) in a vacuum furnace. The alloy was then solution-treated, cold-worked (25% and 50%) and aged. The microstructure and properties (mechanical and electrical) were determined progressively at different stages of heat treatment of the alloy. The tensile strength of this alloy was found to be comparable to that of other precipitation (age) hardened alloys like Cu-Cr, Cu-Zr, etc. The electrical conductivity of the aged alloy was found to be 43% IACS. But when the aged alloy was subjected to 10000 C for 2h and quenched to retain the precipitates stable at this temperature, it showed electrical conductivity of 95% IACS. The precipitates were separated from the copper matrix by electrolysis and subjected to X- Ray Diffraction (XRD) analysis to determine the composition and concentration of different precipitate phases formed in the copper matrix. The stable precipitates at 10000 C were found to be Fe2Zr, ZrB2, Fe4Cu3, and CuZr. Also the types of precipitates stable at temperatures of 6000 C and 8000 C were determined.
- May 31, 2010
Copper and Copper Alloys – Newer Materials and Processes - P. Sriram, K. V. U. Praveen & Ch. Visweswara Rao (Vol. 56, No. 4, April 2010, Page 25-33)
Copper and copper alloys are versatile in their application and are economical for the manufacture of engineering components. There is a copper alloy for mundane applications like plumbing and also for sophisticated electronics uses and a suitable method for making them. The review highlights some details of newer materials, their applications and innovative processes which enhance strength, quality and saleable yields. New materials include high conductivity Cu-Fe-P-Zr, Copper MMC, Cu-Mg-Fe etc.; spinodal alloys, heat-treated aluminium bronzes, high strength manganese bronzes and lead-free bronzes. The processes discussed include pressure diecasting of copper and brasses, permanent moulding of high conductivity copper, LPDC of brass and aluminium bronze, spray castings, metal foams, turbo-charged high-leaded copper alloys and equa castings. The paper includes mechanical properties, microstructures, photos of typical parts and application details.
- May 31, 2010
Development of a Semi-Solid Aluminium Casting for a Near-Net-Shape Automobile Component - Hamsa Lakshmi, M.C. Vinay, R. Raghunath, Pramod Kumar, V. Ramanarayanan, K. S. S. Murthy & P. Dutta (Vol. 56, No. 3, March 2010, Page 42-46)
This study reports an in-house development of a semisolid aluminium alloy A356 casting of an automobile component using the thixocasting route. As a first step, the alloy is electromagnetically stirred and solidified to produce a billet with non-dendritic microstructure. The microstructure depends on several process parameters such as stirring intensity, stirring frequency, cooling rate, melt initial superheat and so on. Through a series of computational studies and controlled experiments, a set of process parameters are identified for producing the best microstructures. Reheating of a billet with non-dendritic microstructure to a semisolid temperature is the next step for thixocasting of components. The reheating process is characterised for various reheating cycles using a vertical-type reheating machine. Temperature is continuously measured by K-type thermocouples inserted in the billets at appropriate locations. The thermocouples are SS sheathed, ungrounded, and mineral insulated to prevent electromagnetic interference. The induction heating cycle is optimised to obtain a near-uniform temperature distribution in radial as well as axial direction of the billet. The choice of reheat temperature and die casting parameters depends on the viscosity variation of the semisolid material with temperature. These parameters are first determined with the help of a computational fluid dynamics (CFD) model of die filling and solidification of the semisolid alloy. The viscosity variation of the slurry, used in the model, is determined experimentally using a specially made rotary viscometer for semisolid alloys. The heated billets are subsequently thixo-cast into an automobile component using a real-time controlled die casting machine. It is found that the castings are near-net-shape, free from porosity, excellent finish and have superior mechanical properties compared to those produced by conventional die-casting processes using the same alloy. This development is a major breakthrough for the Indian foundry industry, as this is the first semisolid component casting produced in India.
- May 14, 2010
Modelling Optimisation and Simulation of Energy (Fuel) Consumption of L.D.O.-Fired Rotary Furnace using Artificial Neural Networks - R, K. Jain, B. D. Gupta & Ranjit Singh (Vol. 56, No. 3, March 2010, Page 37-41)
Energy consumption is major problem being faced by the ferrous foundries. The natural sources of energy - coal, oil, gas etc. are depleting fast. As per the survey conducted and reports published by several national & international agencies, the energy consumption in Indian ferrous foundries is much more above the required limits and has to be drastically reduced. This paper deals with modelling and simulation of energy (fuel) consumption of LDO-fired rotary furnace using artificial neural networks. These experimental investigations on the rotary furnaces produced excellent results. Not only the fuel consumption and emission levels were drastically reduced, but the performance was also improved considerably. The multilayer feed forward modelling method (with two hidden layers) of artificial neural network contained in MatLab software is used for modelling and simulation of energy (fuel) consumption.
- May 14, 2010
Maximising Sand Recovery in the Foundry – Mark Fenyes (Vol. 56, No. 3, March 2010, Page 32-36)
As the disposal of foundry sand becomes more of a worldwide environmental issue and with spiralling costs associated with landfill, the foundry must optimise the sand waste stream by utilising the latest re-processing technology. An overview of the present options available to foundries to maximise their sand recovery is examined. The primary topics covered are (i) Primary and Secondary Attrition, (ii) Thermal Reclamation (iii) Chromite and other mineral recovery. Although primarily aimed at users of No-bake sand systems, the subject of greensand reclamation, i.e. spent greensand back to core room is also covered.
- May 14, 2010
Physical Metallurgy and Melting Practice of Nitrogen-Bearing Austenitic Stainless Steels - Aniruddha A. Gadhikar, C. P. Sharma , D. B. Goel, Ashok Sharma & S. K. Goel (Vol. 56, No. 3, March 2010, Page 23-31)
The physical metallurgy and melting practice of nitrogen bearing austenitic stainless steels are discussed. Nitrogen, being additionally beneficial than carbon, is considered to be an important alloying element in versatile applications. The various alloying elements present in the nitronic steels influence the microstructure and end properties of the steels. The steel making process consisting of conventional ferroalloy additions followed by pressurised electroslag remelting (PESR) has been discussed as a commercial production method for these steels. The prospects of nitrogen alloying in the industrial applications has also been elaborated.
- May 14, 2010
Automated Mechanism for Pick and Place of Dead Weight - Prof. V.R .Naik, Prof. V.P. Gaikwad, Mr. Amod Kulkarni & Mr. S.A. Kulkarni (Vol. 56, No. 2, Feb 2010, Page 47-51)
Conventional method of manually placing weights4 on the mold box to suppress the box lift after pouring was employed in the foundry. The method had a number of drawbacks and did not completely serve the purpose of eliminating the box lift. The castings produced in the concerned foundry required placing of heavier weights. Handling of weights, uneven distribution of weight on box, box lift due to insufficient weight, possibilities of accidents were some of the problems encountered in the conventional method. To overcome these problems, automated mechanism for pick and place of dead weight was proposed. The foundry already had a rectangle shaped transfer line where activities such as pouring, cooling, and breaking of molds were carried out. This helped in the development of pick and place mechanism. The paper explains the design and development of pick and place mechanism consisting of weight calculation, design of elements in the mechanism, casting and execution of the proposed work.
- March 26, 2010
Remediation of Arsenic from Contaminated Water Using Tata’s Granular Blast Furnace Slag (TGBFS) - Anuj Kumar Shrivastava (Vol. 56, No. 2, Feb 2010, Page 43-46)
In the arena of eco-toxicological world arsenic pollution is a matter of alarming concern. The intake of arsenic contaminated water having concentration above the permissible limit causes arsenic poisoning in living beings. In present study batch mode laboratory experiments were carried out using adsorption technology for remediation of arsenic from contaminated water making use of Tata’s Granular blast furnace slag (TGBFS). A significant amount of arsenic is removed by adsorption onto TGBFS. The parameters like pH, contact time, temperature etc. were studied to find out the adsorption capacity of the adsorbent – TGBFS.
- March 26, 2010
Production of Heavy and Thick Ductile Iron Castings (Process Review and Potential Defects) - Pierre-Marie Cabanne, Chantal Labrecque, Gene Murratore & Hans Roedter (Vol. 56, No. 2, Feb 2010, Page 33-42)
Heavy-section Ductile Iron (D.I.) castings have been in production and utilisation for nearly the entire 60 year life of D.I. as an engineering material. There has been an increase in demand for heavy-section D.I. castings over the past 10 years, particularly for energy applications. Heavy-section D.I. has also made inroads into wind turbines, compressors, water turbines, and marine energy applications. In early applications, design engineers often converted gray cast iron components to D.I. without taking full advantage of the higher mechanical properties. Improvements in D.I. production, optimisation of mechanical properties, as well as the use of modelling software and computer simulation have enabled foundry engineers and designers to optimise many of the designs utilising heavy-section D.I. Advances in processing technology have also increased the mechanical properties and consistency of those properties. New moulding and filling techniques have improved the castability of complex shapes and designs. Productivity improvements at the foundry level have made D.I. price competitive with competing materials such as steel castings and forgings, as well as steel weldments. This paper addresses some production recommendations, “field experiences”, and technology advancements, supported by Rio Tinto Research and Development.
- March 26, 2010
Semi Solid Casting-A New Concept - Anjan Prodhan (Vol. 56, No. 2, Feb 2010, Page 27-32)
The author proposed a new method of semisolid treatment using 50 Hz AC electric current (ECT). ECT imposes electro-hydrodynamic (EHD) forces, that is, both normal and tangential forces at the interface of fluid. The present study deals with two types of alloy system with same liquidus to solidus temperature range but having different melting points and density. It is observed that the effect of ECT (or EHD) is similar to electromagnetic stirring (EMS) used in semisolid manufacturing (SSM) process. However, the energy consumption for such treatment is appreciably low in ECT compared to EMS. In ECT the energy consumption depends on the density of the alloy. The objective of the present study is to verify the effectiveness of electric current treatment (ECT) or electro-hydrodynamics (EHD) during sand casting of aluminium and copper alloys.
- March 26, 2010
Casting Defect Analysis Through Metallographic Examination - S. K. Paknikar (Vol. 56, No. 1, Jan 2010, Page 47-55)
Casting defects or rejection analysis is a daily problem faced by all foundrymen. Due to open Global Market, it is imperative to have close control over rejection levels of castings. Global Buyers always demand stringent metallurgical quality specifications and strict delivery schedules which foundryman has to meet to have win win situation in export of castings of all types. Casting defects not only affect production schedules but also increase production cost per tonne of good castings. Therefore, systematic approach to casting defect analysis is the need of the hour. If the diagnosis of casting defect is incorrect, the remedial measures taken may not help to eliminate the defect but it may induce new casting defects to occur in the castings. With this concept in mind author has done intensive study in casting defect analysis with the help of macroscopic and microscopic examination to arrive at root cause of casting defects particularly when the appearance of defects is identical and confusing to analyse by visual examination. This paper gives specific case studies of casting defect analysis by using Foundry Metallographic Techniques, which have been proved to be successful. Thus metallographic examination is a practical tool to casting defect analysis to reduce rejection levels and down cost of production.
- February 26, 2010
Carbon Credits in India: Way to Sustainable Development - Sunila V. Talekar and Shashilata S. Dubey (Vol. 56, No. 1, Jan 2010, Page 42-46)
Clean development mechanism (CDM) projects are helping to promote sustainable development criteria in developing countries. India stands at top in CDM project market with highest number of registered projects as well as issued Certified Emission Reductions (CERs). It has been estimated that there is a potential for Green House Gas (GHG) emission reduction options in Indian Foundry sector. In India, there are more than 5,000 foundry units, having an installed capacity of approximately 7.5 million tonnes per annum amongst which around 95% of them falls under small-scale industry category. Paper refers to the projects, technologies used and future prospects under foundry sector (Ferrous and Non-ferrous metal industries). This paper also assesses the possible sector-wise opportunities through which India can have much better prospects in terms of carbon credits. Carbon credits through Clean Development Mechanism projects in India are helping in mitigation of climate change with new sources for foreign investments.
- February 26, 2010
Influence of Microstructure and Turning Inserts on Machinability and Surface Characteristics of Hypereutectic Al-Si Cast Alloys - K G Basavakumar, P G Mukunda & M Chakraborty (Vol. 56, No. 1, Jan 2010, Page 35-41)
The microstructures, machinability and surface characteristics of hypereutectic Al-Si cast alloys were studied after various melt treatments like refinement and modification. Results indicate that combined refined and modified Al-17Si-4.5Cu cast alloys have microstructures consisting of uniformly distributed primary silicon, interdendritic network of fine eutectic Al-Silicon and fine CuAl2 particles in the interdendritic region. These alloys exhibited better machinability and surface finish in the cast condition as compared with the same alloy subjected to only refinement or modification. Performances of the turning inserts (Un-coated, PVD and Polished CVD diamond-coated) were evaluated in machining hypereutectic Al-Si cast alloys under dry environment using a lathe. The Polished CVD diamond-coated insert outperformed the Un-coated or PVD-coated cutting inserts which suffered from sizeable edge buildup leading to higher cutting force and poor surface finish. The Polished CVD diamond-coated insert shows a very small steady wear without flaking of the diamond film during cutting. This paper attempts to investigate the influence of refinement, modification and combined action of both on the microstructural changes in the hypereutectic Al-Si cast alloys and their machinability and surface finish when different turning inserts used.
- February 26, 2010
Application of Computer Simulation on Large Size Steam Turbine Casing - J.Y. Lee, W.J. Jeong, Y. H. Yim & J. H. Lee (Vol. 56, No. 1, Jan 2010, Page 31-34)
The quality requirements for the steam turbine casing for fossil power plant are extremely high because the operation conditions are severe such as 566°C of the steam temperature and 241.3 bars of pressure. And such conditions are going to much severer direction due to demand of higher efficiency and clean environment. In addition, the shape of casting is complicate with many holes and the wall thickness is thin comparing with the huge size. Therefore, it is difficult to make defect-free casting. The bigger casting, the more possibility of defects. To reflect the real manufacturing condition, the thermal conductivities and heat transfer coefficient (HTC) of moulding materials was measured. Modifying casting designs with the aid of computer simulation prior to real pouring, the best design was selected and the casting was poured.
- February 26, 2010
10-year Survey of Computer Applications in Indian Foundry Industry - Durgesh Joshi & B Ravi (Vol. 56, No. 1, Jan 2010, Page 23-30)
A 10-year survey of computer applications in Indian foundry industry was conducted by IIT Bombay starting in 2000 to understand the penetration of software technologies as well as the benefits and concerns. The survey covered 216 organisations from all over India (159 foundries and tool-makers, 30 OEM firms, and 27 consultants, researchers and academicians). The foundries represented all major metals, processes and capacities. The survey shows a rapid increase in the penetration of computer applications over the last ten years. Today, 100% of the foundries surveyed use Internet and 75% use CAD/CAM, with reported benefits of customer satisfaction, faster development and cost reduction. In contrast, only 25% of those surveyed use simulation (either in-house or out-sourced), although over half of the participants reported the benefits of simulation in quality assurance and yield improvement. On average, foundries using CAD/CAM and simulation tools reported 30% faster casting development and 50% lower rejection rate, compared to foundries that do not employ these technologies. Five years back, the main concern about both CAD/CAM and simulation technology was cost, whereas today the concerns have shifted to technical support and trained manpower availability. The survey provides many such insights useful for technology strategy planning at foundry level, cluster level, and national level.
- February 26, 2010
Hot Spot Prediction Using Vector Element Method and Validation Using Simulation – A Case Study - M.Bhuvaneswari, K.Gowrisankar, B.Sakthivel Murugan & V.Jaiganesh (Vol. 55, No. 12, Dec 2009, Page 48-54)
Hot Spot Prediction Using Vector Element Method and Validation Using Simulation – A Case Study M.Bhuvaneswari, K.Gowrisankar2, B.Sakthivel Murugan3 and V.Jaiganesh4 1, 2, & 3 Final Year B.E. Student, Department of Prod. Engg., PSG College of Technology and 4 Senior Lecturer, Department of Prod. Engg., PSG College of Technology ABSTRACT: This paper attempts to systematically apply vector element method to predict the location of hot spot in a critical automotive cast component. The methodology as well as the step by step approach to the identification of hot spot location has been explained. This could be of immense benefit to foundrymen who would like to apply the same for their castings in order that sound castings could be produced by way of improved and rational feeder design. The location of hot spot predicted using this method was validated by simulation using a finite element method casting software and both the results are in good agreement.
- January 29, 2010