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 martensiticrnstainless steel (0.025C-13Cr-Ni-Mo) seamless pipe is investigated. No retained austeniternwas observed in as quenched modified 13% Cr steel pipe. Retained austenite in the modifiedrn13% Cr steel pipe was formed at tempering period and its volume was affected by temperingrntemperature. The rest potential and the pitting potential for modified 13% Cr steel pipe werernindependent of the retained austenite content. There is no harmful influence of retainedrnaustenite observed on corrosion resistance and pitting resistance for modified 13% Cr steelrnpipe. The SSC resistance for higher retained austenite content steel was higher than thatrnfor lower retained austenite content steel. The precipitated Cr and Mo decreased with thernincrease in austenite content. In other words, the effective Cr and Mo for corrosion increasernwith the increased in austenite content. Higher content of retained austenite reduced thernhydrogen content in steel and SSC susceptibility of modified 13% Cr steel pipe.