饱和H2S水溶液中L360管材疲劳裂纹扩展试验研究

摘要

Crack would occur and grow in local hydrops area when acid environment was formed because of acid gas in gas pipeline. Crack growth rate would increase in fluctuating load which decrease the service time and strength of pipeline. Fatigue crack growth test was conducted in saturated hydrogen sulphide solution with SENB specimens which was machined from L360 pipeline. Test results showed that fatigue crack growth rate is faster in saturated hydrogen sulphide solution than that in air. Fatigue crack growth rate increases with the decrement of frequency. Brittle fracture is the principal failure model in crack propagation surface,transgranular fracture and intergranular fracture are major fracture mode,the portion of transgranular fracture area in fracture surface would increase as frequency decrease.%输气管道中的酸性气体在管道局部积液处形成酸性环境会促使裂纹的形成和生长。交变载荷作用下裂纹扩展速度增大，降低了管道的寿命和强度。采用服役中的L360管道加工成三点弯曲试样在饱和H2S水溶液中进行疲劳裂纹扩展试验。试验表明，饱和H2S水溶液中裂纹扩展速度大于空气中裂纹扩展速度，频率越低，裂纹扩展速度越快；扫描电镜观察显示饱和H2S水溶液中裂纹扩展断面以脆性断裂为主，穿晶断裂和沿晶断裂为主要破坏形式，频率越低，穿晶断裂所占面积越大。