低合金超高强度钢的晶界性质对应力腐蚀断裂行为的影响

在３０Ｃｒ３ＳｉＮｉＭｏＶ、３７ＳｉＭｎＣｒＭｏＶ和４２ＣｒＭｏ三种钢上用俄歇能谱等方法研究了原奥氏体晶界的性质对应力腐蚀断裂行为的影响。结果表明在淬火或低温回火马氏体组织中的原奥氏体晶界上，存在着一个用电镜也难以观察到的碳化物薄层，它是导致钢容易发生应力腐蚀沿晶脆断的主要原因。高温回火后，晶界碳化物聚集粗化以及晶内碳化物的大量析出，导致沿晶断裂倾向性减小和断裂抗力ＫＩＳＣＣ值升高

EFFECT OF GRAIN BOUNDARY PROPERTY ON STRESS CORROSION CRACKING FOR ULTRA HIGH STRENGTH STEELS

The effect of grain boundary carbide on stress corrosion cracking (SCC) for 30Cr 3SiNiMoV, 37SiMnCrMoV and 42CrMo steels have been investigated. The results showed that there was a thin layer of carbide on the austenitic grain boundaries of quenching and low temperature tempering microstructures, which can not be detected even using TEM, resulting in SCC along the sustenitic grain boundaries. After high temperature tempering, the granular carbides precipitated along the grain boundaries and within grains, resulting in the decrease of intergranular SCC and the increace of K ISCC .