Influence of electrode current on mechanical and metallurgical characteristics of hot wire TIG welded SS304HCu austenitic stainless steel and P91 ferritic steel dissimilar joints

The current work focusses on the effect of electrode current on the strength and metallurgical properties of hot wire TIG welded joints of SS304HCu austenitic stainless steel and P91 ferritic steel. The joints were developed with an electrode current of 134, 170, and 205 amperes at a constant heating current of 100 amperes and a wire feed speed of 1700 mm/min. A study of microhardness along the joint boundary was also carried out. Tensile properties of the welded joint were also studied to understand the effect of process parameters. As a result of this study, it was found that joints made at an electrode current of 170 amperes, a wire feed speed of 1700 mm/min and a heating current of 100 amperes showed a maximum tensile strength of 664 MPa compared to other joints. The microstructure of the interface was analyzed using optical microscopy. An EDS analysis was also carried out to understand the composition in the area of the interface. The microstructure of the welded joint's surface is directly related to the tensile strength of the joint.