煤制天然气中氢对X80钢螺旋焊管力学性能的影响

近年来,我国多项煤制天然气示范工程投入运行,X80钢螺旋焊管常用于天然气长输管道建设,其与煤制天然气的相容性直接影响了长输管道的服役寿命和安全可靠性。为研究煤制天然气对国产X80钢螺旋焊管的力学性能影响,分别从埋弧螺旋焊管的母材和螺旋焊缝处取样,在总压为12 MPa,氢气分数为0,1vol%,2.2vol%,5vol%的模拟环境中分别进行慢应变速率拉伸试验和疲劳裂纹扩展速率试验。试验结果表明:含氢量5vol%以下时,煤制天然气对国产X80管线钢强度性能影响很小,但对塑性性能有一定影响,对疲劳裂纹扩展性能影响很大,煤制天然气中氢对母材的疲劳裂纹扩展性能劣化影响比螺旋焊缝严重。

Effects of Hydrogen in Synthetic Natural Gas on Mechanical Properties of X80 Steel Spiral Welded Pipe

In recent years,many synthetic natural gas demonstration projects have been put into operation in China.X80 steel spiral welded pipes are often used in construction of natural gas pipelines.Their compatibility with synthetic natural gas directly affects safety and reliability of long-distance pipelines.In order to study the effect of synthetic natural gas on mechanical properties of domestic X80 steel spiral welded pipes,samples were taken from base metal and spiral welds of submerged arc spiral welded pipes.The total pressure was 12 MPa and hydrogen fraction was 0,1vol%,2.2vol%and 5vol%,respectively.Slow strain rate tensile test and fatigue crack growth rate test were performed in a simulated environment.The test results show that when hydrogen content is below 5vol%,synthetic natural gas has few effects on strength properties of domestic X80 pipeline steel,but has some effects on plastic properties,and great effects on fatigue crack growth performance,the fatigue crack growth performance degradation of base metal is more severe than that of spiral welds.