자동차 배기계용 페라이트계 스테인리스강의 내식성에 미치는 결정립 크기의 영향

Abstract

The effects of grain size on the corrosion resistance of 429EM ferritic stainless steels for automobile exhaust system were investigated. Using specimens held at maximum service temperature of 950℃ for 10~70 hours, electrochemical polarization tests were conducted. While corrosion current density, Icorr, was influenced little by grain size, pitting potential, Ep, was increased with an increase of grain size. And also it was thought that sensitization at grain boundary occurred when the specimen were held at 950℃ for above 50 hours because of the dissolution of precipitates and grain coarsening.