Optimization of A-TIG welding process parameters for RAFM steel using response surface methodology

In the present work, the optimization of Activated TIG (A-TIG) welding process parameters to achieve the desired weld bead shape parameters such as depth of penetration, bead width, and heat-affected zone (HAZ) width have been carried out using response surface methodology (RSM). The main problem faced in fabrication of weld joints is the selection of optimum combination of input variables for achieving required quality of welds. This problem can be solved by development of mathematical model and execution of experiments by RSM. Central composite design of RSM has been used to generate the design matrix for generating data on the influence of A-TIG welding process parameters. The input variables considered were welding current, torch speed, electrode tip angle, and arc gap. The response variables considered were depth of penetration, bead width and HAZ width. A second-order response surface model is developed for predicting the response for the set of given input process parameters. Then, numerical and graphical optimization is performed using RSM to obtain the desired depth of penetration, bead width, and target HAZ width using desirability approach.