摘要
采用电化学试验、交流阻抗谱测试、失重试验、中性盐雾试验及SEM、EDS、XRD分析,研究了不同热处理工艺下塑料模具钢P20的耐腐蚀性能,并对腐蚀机制进行了研究。研究结果表明,860℃空冷得到的贝氏体/马氏体双相组织和860℃油冷得到的单相马氏体组织的耐蚀性优于785℃油冷得到的铁素体/马氏体双相组织。组织为贝氏体/马氏体及马氏体的试样分别经过450和620℃回火后,马氏体及贝氏体发生分解,碳化物大量析出,耐蚀性下降。经电化学试验后,试样表面腐蚀产物分为两层,外层为疏松的FeOOH,内层为致密的Fe3O4;阳极反应为铁的溶解,阴极反应为析氢反应。钢在0.5mol/L的NaCl溶液中的点蚀主要发生在夹杂物周围。
Effect of heat treatment process on corrosion performance of plastic die steel P20 and mechanism for corrosion were studied by electrochemical test, electrochemical impedance spectrum test, weight loss test, neutral salt spray test, SEM, EDS and XRD. It is found that the steels with bainite/martensite quenched at 860℃ by air cooling or martensite quenched at 860℃ by oil cooling have better corrosion resistance than the steel with ferritic/martensitic quenched at 785℃ by oil cooling. After the samples with bainite/martensite or martensite are tempered at 450 and 620℃ respectively, martensite and bainite decompose and a lot of carbides precipitate, leading to a poor corrosion resistance. After electrochemical test, the outer layer of corrosion product on the surface of the samples is loose FeOOH and the inner layer is relatively dense Fe3O4. The anode reaction is mainly dissolution of Fe and the cathode reaction is generation of hydrogen. Pitting mainly occurs around inclusions in NaC1 solution of 0.5 mol/L.
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2014年第10期74-81,共8页
Journal of Iron and Steel Research
关键词
P20
热处理工艺
耐蚀性
点蚀
P20
heat treatment process
corrosion resistance
pitting
作者简介
作者简介：赵鹏翔（1989-），男，硕士；E-mail：zhaopengxiang11@126．com；
