Mechanical properties of dissimilar galvanized steel – 304L stainless steel weld

Abstract

304L stainless steel (SS) is used in several industrial and structural applications. In many such applications, 304L SS is welded to galvanized steel (GS). The high temperatures generated during welding may result in diffusion of the molten zinc into 304L SS and result in embrittlement. The present paper studies the effect of various welding parameters on the mechanical properties of the weld joint between 304L SS and GS. The welding parameters varied were heat input, shielding gas combination and presence and absence of zinc coating. GS plate was welded to 304L SS plate in 1G position using 309L filler metal by gas metal arc welding (GMAW). The samples after welding were subjected to tensile and bend test. Microhardness was measured along the weld cross-section. The ductility was found to be affected by the welding parameters while the yield strength (YS) and ultimate tensile strength (UTS) values were similar for all the samples. Samples subjected to bend test showed no cracks and the compressive strengths were found to be similar. Microhardness measurements showed that there was a sharp increase in the hardness values at the heat affected zone (HAZ) on the GS side and a sharp drop at the HAZ of the SS side in case of all samples. Microstructural characterization of the welded samples was carried out by optical and scanning electron microscopy along the cross-section.