Analysis of Dissimilar Metal Welding of 1020 Mild Steel and 304 Stainless Steel

Abstract

Joining of dissimilar metals causes a steep gradient of the thermo-mechanical properties along the weld. A variety of problems come up in dissimilar welding like cracking, large weld residual stresses, migration of atoms during welding compressive and tensile thermal stresses, stress corrosion cracking, etc. Weld residual stress and thermal stress have been analysed for dissimilar metal welding of 304 stainless steel to 1020 mild steel taking 302 stainless steel as the filler metal. Similarly taking strain developed as an index the susceptibility of the welded joint to stress corrosion cracking have been studied. It is found that when the filler metal is replaced by Inconel 625 significant improvement is obtained in the welded joint in terms of reduction in stress developed and stress corrosion cracking. Also the problem of carbon migration is eliminated by the use of Inconel 625 as a weld filler metal due to the resistance of nickel-based alloys to any carbon diffusion through them.