Characteristics of stainless steel-galvanized steel joint: Effect of stainless steel composition and welding parameters

Stainless steel is welded to galvanized steel in various structural applications. The present study deals with studying the effect of zinc on the properties of weld joint between galvanized steel and stainless steel. Welding of stainless steel and galvanized steel was done by varying various parameters like composition of the shielding gas, presence/absence of coating and composition of stainless steel (304L and 316L grades). After the samples were welded, they were subjected to tensile test, bend test, micro hardness study, corrosion test and microstructural characterisation. These tests revealed that the samples in which the galvanized coating was removed showed better ductility and the samples which were welded by using 304L stainless steel also showed better ductility overall. The samples which were welded using 96%Ar + 2%He + 2%O-2 as the shielding gas produced better ductility as a result of the "hotter arc" generated because of helium in the gas. Yield strength and ultimate tensile strength remained similar across all the samples. Images of the weld bead obtained from scanning electron microscope revealed that the zinc coating close to the weld bead evaporated during welding which in turn could condense and diffuse into stainless steel thereby making it brittle. (C) 2019 Elsevier Ltd. All rights reserved.