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    氢气环境中X60管线钢疲劳裂纹的萌生与扩展行为

    Initiation and Propagation Behaviors of Fatigue Cracks in X60 Pipeline Steel in Hydrogen Environment

    • 摘要: 在总压12 MPa、10%(体积分数)氢气环境中对X60管线钢进行疲劳寿命及疲劳裂纹扩展试验,研究了X60管线钢在氢气环境中的疲劳裂纹萌生及扩展性能,并探究了预充氢及加载频率对结果的影响。结果表明:当加载频率为1 Hz时,氢气缩短了X60管线钢疲劳裂纹的扩展寿命,预充氢10 h则会同时降低裂纹萌生寿命和扩展寿命;在10%氢气环境中,加载频率为1 Hz和2 Hz时,X60管线钢的疲劳寿命相近,但加载频率降为0.5 Hz时,裂纹萌生寿命明显下降,疲劳寿命也随之下降;在10%氢气环境中疲劳裂纹扩展速率是无氢环境中的9.56倍,并且氢气降低了裂纹扩展所需的应力强度因子范围门槛值ΔKth

       

      Abstract: Fatigue life and fatigue crack growth tests were performed on X60 pipeline steel in a gaseous environment containing 10% (volume fraction) H2 at a total pressure of 12 MPa. The fatigue crack initiation and propagation behaviors of X60 pipeline steel in a hydrogen environment were investigated, and the effects of hydrogen pre-charging and loading frequency were examined. The results show that hydrogen reduced the fatigue crack propagation life of X60 pipeline steel under a loading frequency of 1 Hz, but its effect on crack initiation life was not significant. Meanwhile, pre-charging with hydrogen for 10 h decreased both the crack initiation life and the crack propagation life under the same loading frequency. In the 10% hydrogen environment, the fatigue life of X60 pipeline steel was close under loading frequencies of 1 Hz and 2 Hz. However, when the loading frequency was reduced to 0.5 Hz, the crack initiation life decreased obviously, leading to a corresponding reduction in fatigue life. In the 10% hydrogen environment, the fatigue crack propagation rate was 9.56 times higher than that in the hydrogen free environment, and hydrogen reduced the threshold stress intensity factor range (ΔKth) required for crack propagation.

       

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