X120管线钢轧板不同厚度处的氢致开裂敏感性研究

Study on HIC sensitivity at different thickness of X120pipeline steel

为研究X120管线钢氢致开裂原因,根据NACE标准TM 2048—2003测试了X120试验管线钢的HIC敏感性,并采用Davanathan-Stachursky氢渗透装置分别测量了其不同轧板厚度处的氢渗透曲线,采用扫描电镜和EBSD技术观察了不同轧板厚度处的微观组织及晶粒取向差分布。结果表明:X120管线钢的HIC裂纹多出现在轧板的次表层;由于轧板次表层的微观组织与晶粒取向差的共同作用,最终导致该处对氢原子的捕获效率最高,HIC敏感性也最强。

To study the hydrogen induced cracking （HIC）of X120 pipeline steel,the HIC susceptibility in H2 S environments of X120 steel of different rolled plate thickness was evaluated by using NACE TM 2048-2003 standard.The hydrogen trapping effi-ciency was investigated by measuring the permeability （J ∞）and the apparent diffusivity （Dapp ）.Field emission scanning electron microscopy （FE-SEM）and energy dispersive spectrometry （EDS）were employed to study the microstructure and the grain mis-orientation distribution,respectively.The results suggested that X120 steel has the highest HIC susceptibility at the subsurface of rolled plate;due to the interaction between the microstructure and the grain mis-orientation distribution,the subsurface of the rolled plate has the highest hydrogen trapping efficiency and the highest HIC susceptibility.