管线钢在近中性pH值溶液中的应力腐蚀

Stress Corrosion Cracking Behavior of Pipeline Steel in Simulated Solution with Near Neutral pH Value

为研究不同强度管线钢在近中性土壤环境中的耐腐蚀性能,模拟近中性土壤环境,采用C型环试样进行浸泡试验、电化学试验(极化曲线)来研究X80和X100这2种高强度管线钢在近中性环境中的应力腐蚀行为,采用扫描电镜(SEM)、X射线衍射仪(XRD)对试验后的试样腐蚀形貌、产物、结构进行了分析。结果表明:在模拟近中性土壤环境下,耐点腐蚀性能X100>X80,加载应力试样<不加载应力试样; 2种材料均表现出应力腐蚀开裂(SCC)敏感性,SCC敏感性X100>X80,说明随着管线钢强度的提高,SCC敏感性增大;应力腐蚀机制为阳极溶解(AD)+氢脆(HE)。

In order to study the corrosion resistance of pipeline steel with different strength in near neutral soil environment,the stress corrosion behaviors of two kinds of high strength pipeline steel( X80 and X100) in near neutral soil environment were investigated using C-type ring samples by immersion test and electrochemical test( polarization curve and EIS). The morphologies and compositions of the corrosion products were analyzed by scanning electron microscopy( SEM) and X-ray diffractometer( XRD). Results showed that in the simulated near neutral conditions,the corrosion resistance of X100 was higher than that of X80,and the loading stress specimens had worse corrosion resistance than non-loading stress specimens. Two kinds of materials exhibited stress corrosion cracking( SCC) sensitivity,and the order of SCC sensitivity was X100>X80,which presented that SCC sensitivity increased with the increase of the strength of pipeline steel. Furthermore,the stress corrosion mechanism belonged to anodic dissolution( AD) and hydrogen embrittlement( HE).