Evaluation of Tensile Strength and Distortion Control in GTAW Weldment of AA 6061 by Taguchi and Grey Relational Approach

Tungsten inert gas welding (TIG) is also known as Gas tungsten arc welding (GTAW) in USA and Wolfram inert gas (WIG) in Germany. This welding process is widely used for producing high welding quality of a variety of materials, specially, for stainless steel, aluminium and titanium. This paper present the influence of a welding process parameters like welding current, gas flow rate, root gap and bevel angle on the output responses such as distortion and tensile strength of Aluminium alloy on AA 6061 material. The experiment is conducted on AA 6061 specimens of single V-groove butt joint of thickness 4mm and length 150 mm. In this paper an L9 orthogonal array of taguchi method is consider with nine experiment runs to optimize the process parameter. Analysis of variance (ANOVA) is used to find the percentage of contribution of each parameter on tensile strength and angular distortion and the purpose to use the analysis of variance is to find out which welding parameters significantly affect the quality characteristic. Analysis has been carried out by using, grey relational analysis, taguchi method, signal to noise ratio and analysis of variance. In Grey relational analysis, an optimised process parameter of TIG welding was obtained, by analysing grey relational grade we found the degree of influence of each parameter on quality target. Distortion measured is carried out with measuring device dial gauge and measuring of tensile strength is carried out with universal testing machine. Finally at the end, a confirmation test was done to compare the estimated value with the experimental value and a error is find which tell about the closeness of experimental value to the estimated value. The regression model were developed using Minitab software.