PRODUCTION ENGG. Volume:92 2011 SEP

Srl	PDF	ARTICLE NAME	ABSTRACT
1		Correlation of Mechanical Properties of Friction Welded Low Carbon Steel to Stainless Steel Joints with Microstructure and Fractography	Steel joints are used in the chemical, nuclear and defence sectors.Some research work has been done on welding of similar as well as dissimilar steel joints. Generally, similar steel joints can be joined by fusion welding techniques like TIG and MIG welding, but in case of dissimilar welds, solid state welding has to be gone in for because of thermal mismatch. In this paper, a low carbon steel-stainless steel combination has been welded using friction welding.The welding parameters include friction pressure, upset pressure, speed of rotation and burn-off length. Speed of rotation has been kept constant in this case. Later, effect of speed of rotation alone with other parameters fixed is reported. Mechanical properties like tensile strength, impact strength and bend angle have been determined and the properties varied depending on friction welding parameters. Microstructures and SEM micrographs have been shown to explain the results.
2		Finite Element Investigations of Material Models in the Machining Simulation of AA6082(T6) Alloy	Aluminium alloys are widely used in the structural industry due to their inherent high strength to low weight ratio. In particular, AA 6082 (T6) is an AlSi1MgMn alloy known for its superior anti-corrosion and anti-oxidation properties combined with its excellent formability and machinability. The T6 temper in particular possesses higher tensile strength than other types. In this paper, a finite element analysis (FEA) of machining of AA 6082 (T6) is presented.Orthogonal cutting experiments were carried out on a tube of AA 6082(T6) material with a cutting speed of 82 m/min and feed rates of 0.102, 0.159, 0.205 and 0.26 mm/rev. The Johnson-Cook (J-C) and Zerilli-Armstrong (Z-A) constitutive equations were implemented in the FE (finite element) code to study the behaviour of AA 6082 (T6) during the machining process. The predicted values for cutting force, chip thickness, shear angle and shear strain were compared with experiments and have been presented in this paper. The FE results for effective stress, strain, strain rate and temperature were analyzed. The simulation results showed good predictive qualities for the J-C model marginally better than the Z-A model for most parameters.
3		Finite Element Simulation of Forging of Aluminium Truncated Conical Sintered Preforms	The present paper deals with the three dimensional finite element simulation of sinter-forging of aluminium truncated conical preforms using DEFORM-3D software, which considers the heterogeneous deformation due to bulging of preform slant sides, composite die-workpiece interfacial friction conditions, preform densification along with compression and inertia effects. The variation of effective strain, effective stress, effective strain rate, forging load and internal energy dissipation with sinter-forging time were analyzed.The distribution of total displacement, effective stress and effective strain in form of contours on the preform surface were obtained. It was found that effective stress, effective strain, effective strain rate and internal energy dissipation increases with the sinter-forging time and die velocity. It was also noted that effective stress and strains were higher at the edges of preform.
4		Multi-response Optimization of Process Parameters in Cold Chamber Pressure Die Casting	The present study aims at investigating the effect of various process parameters in a high pressure die casting process on the properties of aluminum alloy LM 6 and optimize the parameters using multi-response optimization methodology. Four process parameters, namely pouring temperature of the molten metal, injection pressure, coating type and cooling method were varied during the study. The output responses measured after casting were the material density, hardness and the surface roughness of the cast part.Injection pressure was observed to be the most significant factor and pouring temperature was observed to be the least significant factor. The empirical modelling equation was developed that can be used to predict the response values during experimental trials involving similar process conditions.
5		Parametric Analysis on Ultrasonic Drilling of Alumina based on Taguchi Method	The ultrasonic machining is a mechanical material removal process which has great potential for machining hard and brittle materials, such as, ceramics, semiconductors and glasses etc. The surface finish of the hole surface drilled by USM can be improved by optimal control of the process parameters. This paper presents the experimental investigation for selecting optimum combination of process parameters, such as, abrasive grit size, slurry concentration, power supply and feed rate in ultrasonic drilling of high alumina (99% Al2O3). Taguchi method with orthogonal array L9(34) has been applied for designing the experimental plan.The surface roughness of drilled holes have been analyzed and optimal settings of process parameters have been determined to achieve the minimum value of surface roughness of holes during ultrasonic drilling of high alumina. The additive models for optimal prediction are validated after conducting the confirmation experiments.
6		Wear and Frictional Characteristics of Some Polymeric Materials for Gears used in Machine Tools	Polymers and composites are being extensively used in various tribo systems, such as, bearings, gears, etc where liquid lubricant cannot be used because of various constraints. An attempt has been made in this paper to study the wear and frictional characteristic of some of these materials under various operating conditions.Authors developed a generalized empirical relationship for wear and coefficient of friction of such materials under variable loading and duration of sliding. Based on the experimental observations, it is possible to arrive at a decision in regard to possible combinations of pressure and velocity of sliding, so as to contain the wear within a specific limiting value.