X80与X100级管线钢裂纹扩展模拟分析

A simulation analysis of crack growth for X80 and X100 pipeline steels

针对高钢级管线钢自止裂性能的问题,利用有限元ABAQUS软件建立裂纹扩展分析模型,对管道内壁已有初始裂纹进行分析,模拟了裂纹从内壁生长到外壁,再沿管道轴向扩展的整个过程,比较了裂纹在X80与X100管线钢中的扩展情况。研究结果表明:X100管线钢裂纹在气体压力作用下迅速扩展,泄漏导致的管道压力降低虽然降低了裂纹扩展速度,但裂纹仍然扩展较快,需施加外部作用才能彻底止裂。当管道裂纹没有扩展时,X100管线钢能较好地抵制裂纹的产生,当裂纹已经发生扩展时,X80管线钢有较好的抵制裂纹扩展的能力。可见,与X100管线钢相比,X80管线钢有较强的抗裂纹扩展能力,现有X100管线钢需要结合X80管线钢才能在工程中推广使用。

To identify the crack arrest property of high-grade pipeline steel, a crack growth analysis model is established with the fi nite element software ABAQUS. The model is used to analyze the initial cracks existing in the inner walls of pipeline and simulate the whole process of crack growing from the inner wall to the outer wall and then axially along the pipe. The crack growths of X80 and X100 pipeline steels are compared. The results have proved that the crack of X100 pipeline steel extends rapidly under the infl uence of gas pressure, although the drop of pipeline pressure caused by leakage reduces the crack growth speed; consequently, external effect is needed to thoroughly arrest the crack. When there is no crack, X100 pipeline steel can effectively resist the generation of crack; when the crack has begun to grow, X80 pipeline steel can effectively resist the crack growth. It is thus clear that X80 pipeline steel has a stronger ability to resist crack growth than X100 pipeline steel. X100 pipeline steel and X80 pipeline steel are preferably combined in engineering application.