Investigating the effect of TIG welding process variables on the mechanical properties of stainless steel-304 pipe welded joints

Abstract Stainless steel weld joint quality optimization research has become necessary due to the rise in sudden welded pipe joint failure. The mechanical characteristics and weld quality are greatly influenced by the combined effect of controllable process parameters. This study sought to determine the ideal parameters and examine how tungsten inert gas welding process factors affected the mechanical characteristics of the stainless pipe weld joint. Welded features such as bead shape, size, and mechanical properties were studied related to the weld controllable factors in order to achieve the desired weld quality. Austenitic stainless-steel samples (AISI 304) having 90mm outer diameter and 5mm thick pipe was used for the study. Data were studied using analysis of variance to evaluate the effect of each factor and validated the model's suitability. The results show that the rate of gas flow had the greatest impact on the tensile strength and hardness, whereas the welding current had the main influential factor on the bending strength. Weld parameters were optimized by applying response surface methodology technic and validated using laboratory tests. According to the experiment, optimum weld parameters were 121.30amp, 14 Lit/min, and 2mm for current, gas flow, and root gap respectively. As a result of these parameters combination, optimized mechanical properties were determined including tensile strength of 1402.601N/mm2, hardness of 61.372HRA, and bending strength of 826.022Nm. The optimized parameters evolved from this research can be utilized in the fabrication process of TIG welding at the industries.