Process Parameter Optimization of A-TIG Welding on P22 Steel

Abstract

In the present study, the Activated Tungsten Inert Gas (A-TIG) welding process parameters for welding of 2.25Cr-1Mo (P22) steel have been optimized to attain desired weld bead geometry. Before fabricating weld joints, it is essential to understand the effect of A-TIG welding process parameters in producing quality weld joints. It is proposed to employ the Response Surface Methodology (RSM) of the design of experiments (DOE) approach to determine the optimum parameters in P22 steel weld joint. First, using RSM, a design matrix will be generated by considering various input variables such as welding current, arc gap, torch velocity and electrode tip angle and the output responses such as depth of penetration (DOP), bead area and heat-affected zone (HAZ) width. Further, regression models were generated to correlate the input variables and output responses. The optimum process parameters to obtain the desired DOP, bead area and HAZ width have been determined mainly by utilizing the regression equations and the desirability approach. The Root Mean Square Error (RMSE) of the predicted and measured DOP, HAZ width, and bead area was minimum 0.2571 mm, 0.1776 mm and 6.628 mm2, respectively. TIG current from 235 to 270 A, arc gap from 2.2 to 2.9 mm and welding speed from 60 to 75 mm/min is obtained from RSM analysis as an optimum process parameter. The study manifest that there is an excellent agreement between the predicted and measured values.