The effect of current on characteristic for welded joint between 316 and 316L stainless steel including microstructure and mechanical properties

Abstract

Arc welding is a method that is widely used for fixed joining process. TIG is most commonly used to weld thin sections of stainless steel and light metals such as aluminum, magnesium, and copper alloys. The process grants the operator greater control over the weld than competing procedures. For this study, the influences of parameters of tungsten inert gas arc welding on the morphology, microstructure, hardness and tensile property, and fracture of welded joints of two kind of material including 316 stainless steel pipe and 316L stainless steel plate have been studied. Results show that the increase of welding current bring about the large amount of heat input in the welding pool, the enlargement of width and deepness of the welding pool, cumulative sigma phase in the matrix of both materials and reducing the chromium carbide percentage in 316 stainless steel welded joint. Arc current of 100A has also been identified as the most suitable arc current used to weld the two and half inches 316 stainless steel pipe. Since it gives the lowest defects and brings the highest value of hardness compared to others. For welding 316L stainless steel plate joint, the most suitable current was identified by 110A since it give the lowest defects and highest value of tensile strength compared to others. However, the value of Hardness is slightly lower than130A.