Influence of Pulse GMA Process Variables on Penetration Shape Factor of AISI 304L Welds

Abstract

Weld geometrical parameters are imperative as these affect weld performance and soundness. A weld penetration shape factor is also indexed as ‘form factor’ that is ratio between weld width (w) and weld penetration (p). The ratio of 3:2 (w:p) is optimum in gas metal arc welding intended for quality welds. Increase in heat input increases penetration shape factor that results in weld shape imperfections at weld root. A larger penetration shape factor is susceptible to surface cracking whether a smaller value is prone to centreline cracking in Grade 304L welds. Hence, efforts have been made to understand direct and interactive effects of heat input on penetration shape factor by implementation of 5-level 3-factors central composite rotatable design using response surface methodology. A predictive model is crafted with the measured response as a function of welding current, arc voltage and shielding gas flow rate. Analysis of variance and confirmatory tests are attempted to ensure the accuracy of mathematical model within permissible limit.