Environment hydrogen embrittlement of pipeline steel X70 under various gas mixture conditions with in situ small punch tests
Environment hydrogen embrittlement of pipeline steel X70 under various gas mixture conditions with in situ small punch tests
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DOI：
10.1016/j.msea.2020.139114
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发表时间：
2020-04-20
期刊：
影响因子：
6.4
通讯作者：
Beak, Un Bong
中科院分区：
文献类型：
--
作者：
Thanh Tuan Nguyen;Park, Jong Seo;Beak, Un Bong
采用小冲杆试验研究了天然气/氢气混合气条件对X70管线钢力学性能的影响。各种气体混合物条件包括0.1、0.5、1、3和5体积%的氢气混合物和三种典型的管道压力水平（5、7和10 MPa）。氢脆（HE）敏感性等级取决于氢浓度，并倾向于增加与氢浓度。氢气混合物条件对弹性弯曲区的屈服载荷影响不显著，而当氢气浓度增加时，最大载荷显著降低。此外，从SP载荷-位移曲线和断口形貌获得的定量参数进行了分析，以表征HE行为。通过计算SP吸收能与氢压的函数关系，确定了HE的韧脆转变和饱和氢压。结果表明，X70管线钢在氢环境中的力学性能强度劣化等级不受暴露时间的影响。
A series of small punch (SP) tests was conducted to investigate the effect of natural/hydrogen gas mixture conditions on the mechanical properties of X70 pipeline steel. The various gas mixture conditions included 0.1, 0.5, 1, 3, and 5 vol% hydrogen blends and three typical pipeline pressure levels (5, 7, and 10 MPa). The hydrogen embrittlement (HE) susceptibility grades depend on the hydrogen concentration and tend to increase with hydrogen concentration. The hydrogen gas mixture conditions have an insignificant effect on the yield load of the elastic bending region, whereas the maximal load decreases significantly when the hydrogen concentrations increase. Moreover, the quantitative parameters obtained from the SP load displacement curves and fracture morphologies were analyzed to characterize the HE behavior. By evaluating the SP absorption energy as a function of the hydrogen pressure, the ductile-brittle transition and saturated hydrogen pressures of the HE were determined. According to the results, the strength degradation grades of the mechanical properties of X70 pipeline steel in the gaseous hydrogen environment were not affected by the exposure time.