Metallurgical evaluations were performed on samples of Type 310 and
aluminized 304 SS after long-term, high temperature exposure in methanol reforming service. The secondary phases were identified and the effectiveness of aluminizing at inhibiting metal dusting was examined. Secondary phases adversely affect the materials service life and repairability. Aluminizing effectively inhibits metal dusting for at least 13-14 years. Metal dusting is most severe in crevices on bare metal.
Key words: Austenitic stainless steel, sigma phase, aluminizing, metal dusting, aluminized Type 304 SS.