高压纯氢环境对X80管线钢焊接接头氢脆敏感性的影响

Influence of high-pressure pure hydrogen environment on hydrogen embrittlement susceptibility of X80 pipeline steel welded joints

关键词:  高压纯氢环境  X80管线钢  焊接接头  氢脆  冲击试验  拉伸试验

Key words:  high-pressure pure hydrogen environment  X80 pipeline steel  welded joints  hydrogen embrittlement  impact test  tensile test

摘要:

目的 研究高压纯氢环境对X80管线钢焊接接头氢脆敏感性的影响，为天然气管道掺氢焊接工艺提供参考。方法 采用冲击试验和慢应变速率拉伸试验，结合SEM断口分析及塑性指标计算，研究了6.3 MPa高压纯氢环境中X80管线钢焊接接头氢脆敏感性。结果 ①6.3 MPa纯氢环境下X80管线钢热影响区和焊缝的强度和塑性指标均有所下降，表现出一定的氢脆敏感性；②试样断口边缘出现脆性断裂的解理形貌，韧性断裂向脆性断裂转变；③塑性指标比值及延伸率下降率计算结果表明，相比于热影响区，6.3 MPa纯氢环境下焊缝的氢脆敏感性更高。结论 在6.3 MPa高压纯氢环境中，X80管线钢焊接接头抗氢脆敏感性显著下降，断面收缩率、延伸率和抗拉强度均低于常压空气环境。

Abstract:

Objective The study investigates the effect of high-pressure pure hydrogen environment on the hydrogen embrittlement susceptibility of X80 pipeline steel welded joints, providing a reference for the hydrogen blending welding process of natural gas pipelines. Method By employing impact tests and slow strain rate tensile tests, combined with SEM fracture analysis and plasticity index calculation, the hydrogen embrittlement susceptibility of X80 pipeline steel welded joints in a 6.3 MPa high-pressure pure hydrogen environment was investigated. Result Firstly, both the strength and plasticity index of the heat-affected zone and weld metal of X80 pipeline steel decreased in a 6.3 MPa pure hydrogen environment, demonstrating a certain susceptibility to hydrogen embrittlement. Secondly, the fracture surface of the specimens exhibited a transition from ductile to brittle fracture, characterized by cleavage facets along the fracture edges. Thirdly, calculation results of the plasticity index ratio and elongation reduction rate indicated that the weld metal exhibited higher hydrogen embrittlement susceptibility compared to the heat-affected zone in the 6.3 MPa pure hydrogen environment. Conclusion The susceptibility of welded joints of X80 pipeline steel to hydrogen embrittlement significantly decreases in a 6.3 MPa high-pressure pure hydrogen environment, with lower section shrinkage, elongation, and tensile strength compared to atmospheric air environment.