A series of fracture toughness and fatigue crack growth rate tests were performed on the X70 pipeline steel base and weld metals under 10 MPa of a natural/hydrogen gas mixture with 1% H₂ blends. It is observed that the 10 MPa gas mixture with 1% H₂ causes a significant reduction in the fracture toughness in both metals. The fatigue crack growth rates are markedly accelerated under the gas mixtures with 1% hydrogen blend compared with the tests performed in ambient air. The obtained fracture parameters serve as inputs for fatigue life assessment analyses under the effect of a hydrogen-containing environment. The observed design fatigue life depends strongly only on the environmental conditions. The design fatigue strength of the structural pipeline exposed to hydrogen is much shorter than that under ambient air owing to the decrease in fracture toughness properties and acceleration of the fatigue crack growth rate.

在X70管道钢基和焊接金属在10 MPa的天然气/氢气混合物和1％H ₂混合物下进行了一系列的断裂韧性和疲劳裂纹扩展速率测试。观察到，具有1％H ₂的10 MPa气体混合物会导致两种金属的断裂韧性大大降低。与在环境空气中进行的测试相比，在混合了1％氢的混合气体下，疲劳裂纹的生长速度明显加快。在含氢环境的影响下，获得的断裂参数可作为疲劳寿命评估分析的输入。观察到的设计疲劳寿命在很大程度上仅取决于环境条件。由于断裂韧性的降低和疲劳裂纹扩展速度的加快，暴露于氢的结构管道的设计疲劳强度比环境空气中的设计疲劳强度要短得多。