Continuous-drive friction welding of 45 steel to 304 stainless steel

The welded structure of dissimilar materials has excellent mechanical properties and other properties such as high wear resistance, corrosion resistance and so on, which are widely applied in equipment manufacturing industries. To meet the urgent demand from motor manufacturing enterprises, the dissimilar metal joint consisted of 45 steel and 304 stainless steel was welded by continuous-drive friction welding process, and the joint with good appearance and superior properties were obtained. Inside the joint, the carbide layer was found at the interface. A very thin ferrite layer was formed near the interface and close to the 45 steel. The austenite grains in the joint at the stainless steel side became finer, while the grains in HAZ was coarsened. The tensile strength of the as-welded joint could reach to 870 MPa, and the joint fractured at the interface, which took the form of brittle fracture. But in microcosmic, there are indications of dimple fracture mode and quasi-cleavage mode.