A study on microstructure and mechanical performance of gas metal arc welded AISI 304 L joints

Abstract

Arc welding is a widely applied process in the fabrication of stainless steel structures. Various difficulties may arise in joining of these steels, particularly if high heat input is used. The main aim of this study is to evaluate the influence of heat input on microstructure of the joint region and thus on the mechanical behavior of gas metal arc welded AISI 304 L austenitic plates. To this end, AISI 304 L plates with a thickness of 5 mm were butt-welded by employing two different heat input values. Detailed microstructural and mechanical characterization were carried out. In addition, the influence of heat input on the microstructure and joint performance values was also determined. The higher heat input resulted in a complete recrystallization at the heat affected zone whereas the base metal microstructure was maintained in the lower heat input joint. Both joints displayed strength matching within the weld region, thus exhibited slightly higher tensile strength than that of the base plate (102 %).