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Tungsten Inert Gas welding is a fusion welding process having very wide industrial applicability. In the present study, an attempt has been made to optimize the input process variables (electrode diameter, shielding gas, gas flow rate, welding current, and groove angle) that affect the output responses, i.e., hardness and tensile strength at weld center of the weld metal SS202. The hardness is measured using Vicker hardness method; however, tensile strength is evaluated by performing tensile test on welded specimens. Taguchi based design of experiments was used for experimental planning, and the results were studied using analysis of variance. The results show that, for tensile strength of the welded specimens, welding current and electrode diameter are the two most significant factors with P values of 0.002 and 0.030 for mean analysis, whereas higher tensile strength was observed when the electrode diameter used was 1.5 mm, shielding gas used was helium, gas flow rate was 15 L/min, welding current was 240A, and a groove angle of 60o was used. Welding current was found to be the most significant factor with a P value of 0.009 leading to a change in hardness at weld region. The hardness at weld region tends to decrease significantly with the increase in welding current from 160-240A. The different shielding gases and groove angle do not show any significant effect on tensile strength and hardness at weld center. These response variables were evaluated at 95% confidence interval, and the confirmation test was performed on suggested optimal process variable. The obtained results were compared with estimated mean value, which were lying within ±5%. [ABSTRACT FROM AUTHOR]

EN-31 had high hardness and compressive strength due to high percentage of carbon. This material is mostly used in manufacturing processes or industries. It is mostly used in auto-parts production industries for manufacturing roller bearing, axle, ball bearing, spindle, shear blades, molding dies etc. Due to high hardness, it is very difficult to machine this material with conventional method. So, non-traditional machining methods are used to process the material. Wire electric discharge machining (WEDM) is one of the non-conventional machining method to process the material. Metal removal rate (MRR) and surface roughness (SR) are of essential in the area of machining process. With the increase requirement of good surface roughness, high cutting rate and making complex geometry, traditional machining methods are substituted at present by nonconventional machining method. In the present research, multi objective grey relational grade is applied for EN-31 after processing it with WEDM. Taguchi L9, orthogonal array (OA) has been employed for planning of experiments. Taguchi method is used to gather the experimental data of input and output response. Grey relational grade (GRG) is applied to investigate the optimum value of input parameters for multi-response Optimization. Scanning Electron Microscopic (SEM) is utilized to examine the morphology of machined surface. [ABSTRACT FROM AUTHOR]

Machining of hard materials such as metal matrix composites (Al/SiC) to a high degree of accuracy and surface finish is difficult. Electrical discharge machining (EDM) is an important process for machining difficult-to-machine materials like metal matrix composites etc. The objective of this work is to investigate the effect of Current, Pulse on Time and Pulse off Time on Metal Removal Rate (MRR) and Tool Wear Rate (TWR) during electrical discharge machining of Stir Casted Al-MMC with 10% SiC reinforcement. The use of EDM oil as a dielectric fluid was employed in the present investigation. A copper tool of diameter 6 mm was used to drill the specimen. An L9 orthogonal array (OA), for the three machining parameters at three levels each, was taken to conduct the experiments. Analysis of variance (ANOVA) was performed to find the significant factors with their percent contributions and optimal levels of the factors; the predicted mean with their confidence interval at 95% level was calculated. The final experiments were performed at the optimal levels and percent error was obtained which was less than 5%. Multiple performance optimizations were performed using Grey relational analysis. The confirmation experiments are performed at the optimized setting suggested by grey relation technique. Scanning electron microscopy was also utilized for the surface morphology and recast layer. [ABSTRACT FROM AUTHOR]