Effect of Process Parameters on Depth of Penetration in Gas Tungsten Arc Welded (GTAW) 202 Grade Stainless Steel Plates Using Response Surface Methodology

The quality of a welded joint is directly influenced by the welding input parameters. Inadequate weld bead dimensions such as shallow depth of penetration may contribute to failure of a welded structure since penetration determines the stress carrying capacity of a welded joint. In this study, the regression model was used to establish a relationship between welding input parameters and depth of penetration for gas tungsten arc welding of 202 grade stainless steel plates. A five level four factor central composite rotatable design (CCRD) with 31 experimental runs was used to conduct the experiments. The process control parameters chosen for the study are welding current (I), welding speed (V), welding gun angle (Ɵ) and shielding gas flow rate (Q). A mathematical model was developed to correlate the process parameters to depth of penetration. The developed model was then compared with the experimental results; it was found that the deviation falls within the limit of a 95% confidence level. Additionally, the results obtained from the mathematical model were more accurate in predicting depth of penetration. The direct and interactive effects of the process parameters are also discussed.