In this study, the hydrogen embrittlement behavior of quenched pipeline steel tempered at 550 °C to 650 °C in a high-pressure hydrogen environment was analyzed. Hydrogen permeation tests and microstructural analyses indicated that the dislocation density of the steel decreases with increasing tempering temperature, while precipitates gradually nucleate and grow. These hydrogen traps interact with hydrogen atoms, resulting in significantly higher diffusible hydrogen content in steel tempered at 550 °C compared to that tempered at 600 °C and 650 °C. Fatigue crack growth (FCG) test results show that steel tempered at 600 °C and 650 °C exhibits significantly better hydrogen embrittlement resistance than steel tempered at 550 °C. This is primarily due to the combined effect of the high hydrogen concentration, high dislocation density and low nano carbide content in the steel tempered at 550 °C, which inhibits dislocation slip and emission, leading to high crack tip stress and rapid crack propagation. In contrast, the low dislocation density and and dispersed nano carbides in steel tempered at 600 °C and 650 °C facilitate some dislocation slip and emission, result in crack tip stress relaxation and reduced crack propagation rate. Properly controlling the initial dislocation density and increasing the density of irreversible hydrogen traps can enhance the strength of materials while improving their resistance to hydrogen embrittlement.

中文翻译：

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高压氢环境下位错和析出相的调控提高管道钢的抗氢脆性能


本研究分析了在高压氢气环境中 550 °C 至 650 °C 回火的淬火管线钢的氢脆行为。氢渗透试验和微观组织分析表明，钢的位错密度随着回火温度的升高而降低，而析出物逐渐成核增长。这些氢陷阱与氢原子相互作用，导致在 550 °C 回火的钢中，与 600 °C 和 650 °C 回火的钢相比，其扩散氢含量明显更高。 疲劳裂纹扩展 （FCG） 试验结果表明，在 600 °C 和 650 °C 下回火的钢比在 550 °C 下回火的钢表现出明显更好的抗氢脆性。 这主要是由于在 550 °C 回火的钢中高氢浓度、高位错密度和低纳米碳化物含量的综合作用，抑制了位错滑移和发射，导致高裂纹尖端应力和快速裂纹扩展。相比之下，在 600 °C 和 650 °C 回火的钢中的低位错密度和分散的纳米碳化物促进了一些位错滑移和发射，导致裂纹尖端应力松弛并降低裂纹扩展速率。适当控制初始位错密度并增加不可逆氢阱的密度可以提高材料的强度，同时提高其对氢脆的抵抗力。