显微组织对超低碳X80管线钢氢致开裂行为的影响

摘要

Normalizing and quenching treatment were carried out on ultra-low carbon X80 pipeline steel,and then the influence of microstructures on the hydrogen-induced cracking behavior of the steel was investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and electron backscatter diffraction (EBSD)technology.The results show that the tested steel before heat treatment owned acicular ferrite structure,and its HIC resistance was better than the HIC resistance of polygonal ferrite structure after normalizing and bainite ferrite structure after quenching.The uniform distribution of high and low angle grain boundaries was of benefit to the improvement of HIC resistance of the test steel,meanwhile high density low-angle grain boundaries could prevent the extend of hydrogen induced crack.%对超低碳X80管线钢分别进行了正火和淬火处理，采用光学显微镜、扫描电镜、透射电镜和电子背散射衍射技术等手段，研究了显微组织对试验钢氢致开裂(HIC)行为的影响。结果表明：未经热处理的试验钢显微组织为针状铁素体，该组织的抗 HIC 性能优于正火后多边形铁素体组织和淬火后贝氏体铁素体组织的抗 HIC性能；大小角度晶界的均匀分布有利于提高试验钢的抗HIC性能，高密度的小角度晶界可以阻止氢致裂纹扩展。