Effect of micro-plasma arc melting on the corrosion resistance of a 0Cr19Ni9 stainless steel SAW joint

摘要

The surface microstructure and the anodic polarization curves in a 1 N H_2SO_4 solution of a 0Cr19Ni9 submerged arc welded joint were studied before and after surface melting using a 4-A micro-plasma arc. The results showed that both the heat-affected zone and the weld metal of the as-welded joint had a lower corrosion resistance than the as-received parent material, while the arc melted joint had a significantly increased corrosion resistance. This increase in corrosion resistance is attributed to a rapid solidification of the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.