Development of Mathematical Model for Percentage of Elongation of TIG Welded Duplex Stainless Steel

Quality strongly depends on good mechanical properties of any manufacturing material. Similarly, quality of Tungsten Inert Gas (TIG) welding of Duplex Stainless Steel (DSS) depends on good mechanical properties like percentage of elongation, ultimate tensile strength etc. Better Percentage of Elongation (PE) is produced using proper welding parameters and their values at the time of TIG welding. In this study, TIG welding has been done on ASTM/UNS 2205 duplex stainless steel materials. A new mathematical model is developed using non-linear regression analysis for the prediction of percentage of elongation. The variables used in the prediction models are selected welding parameters like welding current, gas flow rate and speed of welding. A residual plot for PE has been developed to validate the mathematical model. Calculation of percentage deviation for PE has been made. Comparison of measured and predicted PE value has been done by graphical representation. The relationship between percentage of elongation and the welding parameters has been illustrated graphically by surface plots and contour plots as well. Combined effects of any pair of input parameters on PE are represented graphically with the help of three-dimensional surface plots. According to this analysis, the models provide good PE with the data used in this study.