Surface treatment of 0Cr19Ni9 stianless steel SMAW joint by plasma melting

摘要

Micro-plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a mi- cro-plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anodic polarization behavior in 0.5 mol/L H_2SO_4 solution. The polarization tests showed that for the as-welded joint both the heat-affected zone and the weld metal decreased in resis- tance 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 is at- tributed to the rapid solidification f the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases its microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.