不同状态高V低合金高强度钢的氢扩散与裂纹扩展  

Hydrogen diffusion and crack growth of a high strength low alloy steel with high vanadium content under different states

作　　者：曾繁宇 程晓英[1] 王庆[1] 李晚晴 任毓文 Zeng Fanyu;Cheng Xiaoying;Wang Qing;Li Wanqing;Ren Yuwen(Institute of Materials,Shanghai University,Shanghai 200072,China)

机构地区：[1]上海大学材料研究所,上海200072

出　　处：《金属热处理》2025年第3期158-166,共9页Heat Treatment of Metals

基　　金：国家自然科学基金(51871145)。

摘　　要：采用金相显微镜、透射电镜(TEM)、电子背散射衍射(EBSD)技术以及X射线衍射(XRD)研究了一种高V低合金高强度钢热轧态与调质态的显微组织、位错以及取向等微观组织特征,同时采用电化学氢渗透技术和疲劳裂纹扩展试验研究了其中的氢扩散和裂纹扩展的行为,建立了微观组织、氢扩散与裂纹扩展之间的关系。结果表明,与热轧态相比,调质态的试验钢中残留奥氏体分解,位错密度降低,钒的碳化物大量析出,不可逆氢陷阱增多,导致氢扩散系数降低和扩散激活能升高,氢更不易扩散,钢的氢脆敏感性下降。在空气和低电流密度充氢下热轧态钢中残留奥氏体的存在使得其拥有比调质态更优的抗裂纹扩展能力,但在较高的电流密度下氢脆会起主导作用,从而使得裂纹扩展速率升高。Microstructural characteristics such as morphology,dislocation density and crystal orientation were studied by using metallographic microscope,transmission electron microscope,electron backscatter diffraction technology and X-ray diffraction in a high strength low alloy steel with high vanadium content under both hot-rolled and quenched-tempered states,respectively.At the same time,the behavior of hydrogen diffusion and crack propagation were also studied by means of electrochemical hydrogen permeation technique and fatigue crack growth test.The aim was to establish the relationship among the microstructure,hydrogen diffusion and crack growth rate.The results show that compared with the hot-rolled state,retained austenite decomposes,the dislocation density decreases,and a large number of vanadium carbides precipitate,leading to an increase of irreversible hydrogen traps in the quenched-tempered state.Consequently,the hydrogen diffusion coefficient decreases,and the diffusion activation energy increases,making hydrogen diffusion more difficult and reducing the susceptibility to hydrogen embrittlement.In air and under low hydrogen charging current density conditions,the presence of retained austenite in the hot-rolled state provides superior crack growth resistance compared to the quenched-tempered state.However,at higher current densities,hydrogen embrittlement becomes dominant,resulting in an accelerated crack growth rate.

关 键 词：低合金高强度钢 V微合金化 调质处理 氢扩散 裂纹扩展 

分 类 号：TG142.1[一般工业技术—材料科学与工程]