The corrosion resistance of 0Cr19Ni9 stainless steel arc welding joints with and without arc surface melting

In order to improve the corrosion resistance of stainless steel welded joints, thin surface melted layers with refined microstructure were produced on 0Cr19Ni9 stainless steel arc welding joints by micro-plasma arc surface melting (MASM). The arc surface treatment changed the anodic polarization behaviour in 1 N H2SO4 solution. The polarization tests showed that for the as-welded joint both the heat-affected zone and the weld metal decreased in resistance to corrosion compared with the as-received parent material while for the micro-plasma arc surface melted joint the corrosion resistance increased significantly. This increase in corrosion resistance as a result of MASM is attributed to rapid solidification of the melted layer. Rapid solidification of the melted layer refines the microstructure, decreases microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.