PARAMETRIC OPTIMISATION OF PULSED – TIG WELDING PROCESS IN BUTT JOINING OF 304L AUSTENITIC STAINLESS

Stainless steels are widely used in thermal power plant, pressure vessels and automobiles components due to their superior fracture toughness, good inter granular corrosion resistance and non-requirement of post process annealing. Heat affected zone decreases the strength of the weld hence Pulsed TIG welding process is carried out to reduce the heat affected zone. This inherent property of the material reduces crack growth at high pressure which leads to the increase in efficiency of the pressure vessels and automobile components, when operated at high pressure. This paper describes the optimization of process parameters like current, voltage, stand-off distance, pulse on time, pulse off time and weld speed, gas flow to improve weld quality. In this work Taguchi method is used to get the optimal parameters. In Taguchi method, L27 orthogonal array is used for experimentation. Further, the experimental values and the various settings of the process parameters are fed as input to Taguchi and hence the S/N ratio values are obtained. Weld speed and input current are found to be the most significant parameters. Finally, the strength of the weld is validated by tensile and bending test