Optimization of gas tungsten arc welding process by response surface methodology

•Gas tungsten arc welding of A516-Gr70 carbon steel were studied.•Simultaneous effects of process parameters on tensile strength were evaluated.•DOE response surface methodology were used for optimization.•Current, welding speed and shielding gas flow rate were optimized.

Gas tungsten arc welding is widely used for connecting of boiler parts made of A516-Gr70 carbon steel. In this study important process parameters namely current, welding speed and shielding gas flow rate were optimized using response surface methodology (RSM). The simultaneous effects of these parameters on tensile strength and hardness were also evaluated. Applying RSM, simultaneous effects of welding parameters on tensile strength and hardness were obtained through two separate equations. Moreover, optimized values of welding process parameters to achieve desired mechanical properties were evaluated. Desired tensile strength and hardness were achieved at optimum current of 130 A, welding speed of 9.4 cm/min and gas flow rate of 15.1 l/min.