夹杂物对30Cr13和StavaxESR马氏体不锈钢耐蚀性能的影响

Effect of inclusion on corrosion resistance of 30Cr13 和 StavaxESR martensitic stainless steels

采用X射线衍射(XRD),扫描电镜(SEM),光电子能谱显微镜(PSEM)并结合电化学阻抗谱(EIS),动电位极化曲线测试等研究了30Cr13钢和StavaxESR钢在不同热处理状态下的微观组织、夹杂物分布及电化学腐蚀性能,并研究了碳化物及夹杂物对其耐蚀性能的影响。结果表明:经过1130℃奥氏体化处理40 min后,分布于退火态30Cr13钢和StavaxESR钢基体中的富Cr型M_(23)C_6碳化物全部固溶且在淬火时未析出,导致其耐点蚀性能提高;30Cr13钢中的夹杂物含量显著高于StavaxESR钢,且主要为(Ti,Al,Ca)N复相夹杂,与基体形成微电池,加速30Cr13钢基体溶解,导致其耐蚀性低于StavaxESR钢。

Microstructure, inclusion distribution and electrochemical properties of 30Cr13 and StavaxESR martensitic stainless steels under different heat treatment conditions were analyzed by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), photoelectron spectromicroscopy(PSEM), electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization test, and the influence of carbides and inclusions on their corrosion resistance was studied. The results show that after austenitizing treatment at 1130 ℃ for 40 min, the rich Cr type M23C6 carbides distribute in the annealed 30Cr13 steel and StavaxESR steel matrix are completely dissolved and do not precipitate during quenching, which leads to the improvement of pitting corrosion resistance of the steels. The amount of inclusions in the 30Cr13 steel is significantly higher than that in StavaxESR steel, and it is mainly composed of(Ti,Al,Ca) N multiphase inclusions, which forms a microbattery with the matrix and accelerates the dissolution of the 30Cr13 steel substrate, resulting in lower corrosion resistance than that of the StavaxESR steel.