制备了单边缺口拉伸（SENT）试样，在0.5 mol/L H₂SO₄+3 g/L NH₄SCN溶液中，以10 mA/cm²的电流密度充氢4 h，采用拉伸试验和三点弯曲试验考察了氢脆对X80管线钢断裂韧性的影响。结果显示：充氢SENT试样的断裂韧性和承载力显著低于母材SENT试样的，使用三点弯曲试验测定的断裂韧性结果较为保守；充氢SENT试样的裂纹比较尖锐，呈现非稳态扩展特征，其塑性变形主要集中于裂纹尖端的局部区域；氢的存在会降低裂纹起裂和扩展所需的能量，促进韧性撕裂过程向脆性断裂转化。

A single edge notched tensile (SENT) specimen was prepared, and hydrogen was charged in 0.5 mol/L H₂SO₄+3 g/L NH₄SCN solution at a current density of 10 mA/cm² for 4 h. The effect of hydrogen embrittlement on the fracture toughness of X80 pipeline steel was comparatively studied by tensile test and three-point bending test. The results show that the fracture toughness and bearing capacity of the hydrogen-charged SENT sample were significantly lower than those of the base material SENT sample. The fracture toughness results measured by the three-point bending test were conservative. Cracks of the hydrogen-charged SENT sample were relatively sharp, showing the characteristics of unsteady state propagation, and the plastic deformation was mainly concentrated in the localized area of the crack tip. The presence of hydrogen would reduce the energy required for crack initiation and propagation, and promote the transition from ductile tearing to brittle fracture.