埋地管线钢应力腐蚀敏感性分析

Sensitivity Analysis on Stress Corrosion of Pipeline Steel in Soil Evironments

采用慢应变速率法对X60管线钢进行模拟土壤和真实土壤的应力腐蚀试验研究。通过试验研究可知:X60管线钢在模拟高pH值和低pH值土壤溶液以及真实土壤中慢拉伸都产生应力腐蚀。这3种介质产生的应力腐蚀都存在敏感应变速率范围,远离该范围,产生应力腐蚀的敏感性下降。同时,运用灰色理论计算灰色关联度对3种腐蚀介质敏感性进行了数据分析。试验结果和灰色理论分析表明:X60管线钢在3种介质溶液中的腐蚀敏感性依次为土壤<1NNa2CO3+1N NaHCO3<NS4。

The laboratory studies on stress corrosion cracking of X60 pipeline steel which represents old pipeline in the simulated soil and the true soil which have been performed by applying the slow strain rate testing.Slow strain rate testing of X60 pipeline steel shows that it could really lead to SCC（Stress Corrosion Cracking） in low pH simulated solution,high pH simulated solution and true soil.For these three mediums,each of them has independent sensitive strain rate.The sensitivities of SCC would decrease when SCC is away from each range.Meanwhile,through the grey relationship is established,while the data analysis about the corrosion sensitivities of three mediums.The experimental results and grey theory analysis indicate that the corrosion sensitivity is true,soi1N Na2CO3＋1N NaHCO3NS4.