Fatigue crack growth model of X80 pipeline steel in hydrogen environment for quantification of hydrogen pressure effect

Abstract

With the increasingly imperious demands for energy transformation and development of hydrogen energy utilization in China,X80 high-strength pipeline steel will face the risks of operating in a hydrogen environment. As the in-service pipeline is subjected to both static load and cyclic load, and the interaction between cyclic load and hydrogen is more complex, the evaluation of properties of pipeline steel in the hydrogen environment must consider both the tensile and fatigue properties. Specifically, the effect of hydrogen on the tensile and fatigue properties of X80 steel was analyzed through the tensile test and the fatigue crack growth test in a high-pressure hydrogen environment. Thus, a fatigue crack growth model of X80 pipeline steel was established to quantify the hydrogen pressure. The results show that hydrogen has no significant effect on the tensile property of X80 pipeline steel. Whereas, a higher hydrogen pressure will lead to a greater fatigue crack growth rate, and the fatigue crack growth rate at the hydrogen pressure of 3 MPa is 10 times that in a nitrogen environment. This indicates that hydrogen has a significant impact on the fatigue crack growth of X80 pipeline steel. In addition, the fatigue property of X80 pipeline steel will become a key factor for the safety design and integrity evaluation of the pipeline in the hydrogen environment.

Keywords

• hydrogen pipeline
• hydrogen-doped pipeline
• pipeline steel
• hydrogen embrittlement
• fatigue
• crack growth model