Microstructure and mechanical properties of gas metal arc welded AISI 430/AISI 304 dissimilar stainless steels butt joints

Abstract

Nowadays, there is an increasing demand for the use of joining dissimilar metals in various industrial applications owing to the economic benefits and better joint performance. Ferritic stainless steel grades is a good alternative for austenitic ones in several applications as they display higher ductility and strength as well as better corrosion resistance in chloride environments. However, the poor ductility and low impact toughness of ferritic stainless-steel welded joints limit their wide-spread application. Thus, the demand for joining dissimilar ferritic and austenitic stainless steels is ever increasing in several engineering applications in various industries such as nuclear power plants, coal fired boilers, automobile manufacturing industry, chemistry and petro-chemistry industries, etc. Therefore, successful joining of these two different types of stainless steel grades using conventional fusion welding methods is rather important. In this study, the weldability of AISI 430 ferritic and AISI 304 austenitic steel plates using gas metal arc welding and the effect of heat input on microstructure and the mechanical properties were investigated. For this purpose, AISI 430 and AISI 304 plates with a thickness of 5 mm were joined using different heat input values. The microstructures evolved in the weld region of the joints and their mechanical properties were determined by detailed optical microscopy investigations, micro-hardness measurements and tensile tests. Thus, the influence of the heat input on the weldability of these two different stainless-steel plates using gas metal arc welding was also studied.