EFFECT OF RETAINED AUSTENITE ON CORROSION ERFORMANCE FOR MODIFIED 13 CR STEEL PIPE

摘要

Effect of retained austenite on corrosion performance of modified 13% Cr martensitic stainless steel (0.025C-13Cr-Ni-Mo) seamless pipe is investigated. No retained austenite was observed in as quenched modified 13% Cr steel pipe. Retained austenite in the modified 13% Cr steel pipe was formed at tempering period and its volume was affected by tempering temperature. The rest potential and the pitting potential for modified 13% Cr steel pipe were independent of the retained austenite content. There is no harmful influence of retained austenite observed on corrosion resistance and pitting resistance for modified 13% Cr steel pipe. The SSC resistance for higher retained austenite content steel was higher than that for lower retained austenite content steel. The precipitated Cr and Mo decreased with the increase in austenite content. In other words, the effective Cr and Mo for corrosion increase with the increased in austenite content. Higher content of retained austenite reduced the hydrogen content in steel and SSC susceptibility of modified 13% Cr steel pipe.