贝氏体/马氏体复相高强钢中的氢陷阱

运用电化学渗透技术研究了传统高强钢(42CrMo)和贝氏体/马氏体复相高强钢(U20Si)中氢的扩散和氢陷阱。结果表明，氢在U20Si钢中的扩散系数远小于在淬火回火的42CrMo高强钢中的。另外，两种材料中氢陷阱的情况不同，U20Si钢中的氢陷阱主要为高度均匀弥散分布的贝氏体/马氏体板条界和薄膜状残留奥氏体，而42CrMo钢中的氢陷阱主要为铁素体/渗碳体界面。U20Si钢中的氢陷阱数量超过42CrMo钢的。力学性能测试表明，U20Si钢的氢脆敏感性低于传统的42CrMo钢的。断口分析显示前者的断口为准解理，后者的断口为沿晶断裂。U20Si钢氢脆敏感性低与其氢陷阱数量多且分布均匀密切相关。

Hydrogen Trapping in Bainite/Martensite Dual-phase High Strength Steel

Hydrogen trapping phenomena in conventional high strength steel (42CrMo) and bainite/martensite dual-phase high strength steel (U20Si) were investigated by electrochemical permeation technique.The diffusion coefficient was calculated from permeation time-lag data.The diffusion coefficient in U20Si steel is less than that of 42CrMo steel.The results show that the situation of hydrogen traps is different in U20Si steel and 42CrMo steel. Hvdrogen traps in the former mainly are dispersedly and uniformly distributed bainite/martensite lath boundaries and retained austenite;but in the latter mainly are ferrite-cementite interfaces.The trap numbers of U20Si steel are more than that of 42CrMo steel.The susceptibility to hydrogen embrittlement of U20Si steel is lower to that of conventional 42CrMo steel.The fracture appearance for the former is quasicleavage;for the latter is intergranular.The lower susceptibility to hydrogen embrittlement of U20Si steel is related to a number of hydrogen traps and its dispersive and uniform distribution.