An investigation into stainless-steel/structural-alloy-steel bimetal produced by shell mould casting

Bimetal consisting of stainless steel (316L) and structural steel (30CrNiMo8) was produced by shell mould casting technique and interface region between two metals was characterized by metallographic examination and mechanical tests. Three types of interface occur during the solidification i.e., due to liquid–liquid steel interaction (Interface I), interaction of solid structural steel–liquid stainless steel (Interface II), and solid–solid interaction (Interface III). It is concluded that the Interface I and II have higher microhardness than the Interface III since the interaction region of Interface I and II has mixture of martensitic and bainitic microstructure. As C diffusion takes place from the structural steel to the stainless steel, Cr and Ni diffuse opposite direction of C diffusion. Mechanical properties of the bimetal were greater than that of stainless steel but smaller than that of structural steel.