Study on welding process of stainless steel/superalloy dissimilar materials

Abstract In this study, dissimilar materials of 321 stainless steel, S-03 stainless steel, and GH3030 superalloy were selected and the argon tungsten-arc welding method was used to explore the welding parameters. The microstructure and properties of three materials after welding were studied. The main mechanism of welding cracks was analyzed by optical microscope and scanning electron microscope. Reasonable welding parameters were established and the dissimilar welding process was realized. The experimental results show that the cracks produced by welding of the three materials are typical welding hot cracks. The crack source originated from the bottom layer and extended to the surface of the welded joint. The main reason for cracking is the formation of low melting point compounds by the segregation of S and Ti elements during the process of self-melting. The welding process of the dissimilar materials can be realized by multi-pass filling welding. Increasing welding speed and reducing heat input are effective ways to improve weld mechanical properties of the welded joint.