Test Method of Intergranular Corrosion for Austenite-ferrite Duplex Stainless Steel

Precipitation of detrimental secondary phases such as σ, χ, R phase, chromium carbides and nitrides will inevitably occur at the grain boundary, phase boundary and its surrounding areas at 300~1 000 ℃ which leads to the formation of Cr depleted zones around grain boundary and precipitation of austenite-ferrite duplex stainless steel. This may seriously deteriorate the intergranular corrosion of the austenitic-ferrite duplex stainless steel in specific environment, so it needs to be accurately measured in the laboratory. The laboratory intergranular corrosion test methods of the austenite-ferrite duplex stainless steel were summarized, including chemical immersion method and electrochemical method. The problems needing attention in the test were put forward, which provided reference for corrosion testers.