On the Influence of Welding Stainless Steel on Microstructural Development and Mechanical Performance

Abstract

In the present work, the influence of welding stainless steel on the microstructural development and associated mechanical performance were investigated. Gas tungsten arc welding (GTAW) process was used to weld 6 mm thick AISI 304L stainless steel using three levels of welding arc energy inputs. Different weld thermal cycles that resulted due to different combinations of heat input used caused significant microstructural changes in the weldments, which consequently affected the tensile and impact properties of these joints. Mechanical and material characterization of these joints have revealed that the weld metal under low welding heat input condition possessed relatively fine columnar dendritic microstructure which resulted in high microhardness and impact toughness of this zone. For every joint, the weld metal exhibited superior mechanical strength (transverse tensile strength, elongation, and Charpy impact energy) than the corresponding heat-affected zone. This work establishes that GTAW process when used for manufacturing operations involving AISI 304L stainless steel fabrications is capable of giving superior mechanical properties provided parametric combinations leading to low welding heat input are used.