Some Studies on Mechanical Properties of AISI 316L Austenitic Stainless Steel Weldments by Cold Metal Transfer Process

Abstract

Cold metal transfer (CMT) process widely employed in automobile industry offers better results in achieving distortion-free joints due to low heat input produced in comparison with the conventional GMAW process. The focus of this research is to explore the impact of CMT process on the microstructural changes and mechanical behavior, i.e., tensile strength, hardness, and elongation percentage of AISI 316L weldments. It was observed that microstructure of HAZ was similar to the base metal, and weldment microstructure is the main factor for the efficiency of joints. The uniaxial tension results revealed that the CMT joints exhibited higher tensile strength (UTS) of 571 MPa compared to base metal strength of 536 MPa. The results of mechanical testing showed an increase in hardness and a decrease in ductility is attributed to the existence of high delta ferrite content in the austenite matrix after welding. Ductile mode of failure was observed in the fracture surface with microvoids and dimple structure.