A STUDY ON THE CHANGES IN MICROSTRUCTURE AND MECHANICAL PROPERTIES OF MULTI-PASS WELDING BETWEEN 316 STAINLESS STEEL AND LOW-CARBON STEEL

In this study, the changes in the microstructures and mechanical properties in the fusion zone and heat-affected zone (HAZ) of the welds between 316 stainless steel and low-carbon steel were investigated. The formation of the morphology of δ – Ferrite including the columnar dendritic and the equiaxed dendritic in either the single-pass welding or multi-pass welding was analyzed through SEM. The recrystallization phenomenon in two regions such as HAZ-1 with grain-refining and HAZ-2 with partial grain-refining was considered as the main cause leading to differences in the microstructure and mechanical properties of the above-mentioned welds. As a result, the hardness, tensile strength and elastic strength of multi-pass welding were higher than those of single-pass welding. The lower elongation of multi-pass welding compared to single-pass welding was also observed