The effect of the welding temperature on the weldability in diffusion welding of martensitic (AISI 420) stainless steel with ductile (spheroidal graphite-nodular) cast iron

In this study, the effect of welding temperature on the weldability in diffusion welding of martensitic (AISI 420), stainless steel with ductile (spheroidal graphite-nodular) cast iron was investigated experimentally under protective atmosphere at various temperatures and constant prescribed pressure blow those which would cause macrodeformation. Microstructure examinations were carried out by SEM and EDS. Hardness values were measured by Hv scale under a load of 200 g along the weld interface, mutual chrome and carbon diffusion were observed on ductile cast iron side and stainless steel side, respectively. On the other hand, as a function of process temperature elevation, increase in the amount carbon and chrome atoms migrated toward to interface, reduction at nodular graphite diameters was also noticed. As a result of all evaluations and tests carried out, it can be said that, best gathered mechanical and metallurgical properties were observed at the specimen bonded at 1100 °C process temperature at 12 MPa, for 20 min.