A sudden change in the geometrical parameters of a material, such as bends, T-branches, and welded joints may increase the stress concentration, which in turn may enhance the diffusible hydrogen concentration. In this study, quantitative evaluations of the effect of stress concentration factors on hydrogen environmental embrittlement (HEE) will be studied based on the mechanical performance of notched tensile specimens with variations in the stress concentration factors (K_t) of the X70 pipeline base and weld metal. To highlight the role of stress concentration, the tests are performed under a 10 MPa gas mixture condition with a low partial hydrogen pressure. The maximum strengths of the notched specimens were nearly consistent across all K_t values. The degree of HEE susceptibility of the base metal increased with increasing K_t value. However, in the weld metal, prominent reductions in the RA occurred at all K_t values. The complex HEE susceptibility of the weld metal can be attributed to the synergistic action of the microstructure heterogeneity and K_t values.

材料的几何参数（例如弯曲，T型分支和焊接接头）的突然变化可能会增加应力集中，而应力集中又会增加可扩散的氢浓度。在这项研究中，将基于缺口拉伸试样的机械性能，随着X70管道基础和焊缝的应力集中系数（K _t）的变化，对应力集中系数对氢环境脆化（HEE）的影响进行定量评估。金属。为了突出应力集中的作用，在低分氢气压的10 MPa混合气体条件下进行了测试。缺口试样的最大强度在所有K _t上几乎一致价值观。母材的HEE敏感性程度随K _t值的增加而增加。但是，在焊缝金属中，在所有K _t值下，RA均显着降低。焊缝金属的复杂HEE敏感性可归因于微观结构异质性和K _t值的协同作用。