高强度管线钢近中性pH土壤应力腐蚀开裂的影响因素

Stress Corrosion Cracking Influence Factors of High Strength Pipeline Steel in Simulated Near-neutral pH Soil Environment

为了有效预防和控制高强度管线钢在近中性p H土壤中的应力腐蚀开裂,采用慢应变速率试验、电化学试验、压力波动试验等方法,对X70和X80管线钢在近中性p H土壤环境中的应力腐蚀开裂敏感性进行了试验研究。对比了X70和X80管线钢的应力腐蚀开裂敏感性指标及在不同外加电位下的电化学试验结果,并选取3个应力比,分析了X80管线钢在近中性p H土壤环境下的压力波动规律。研究结果表明,在近中性p H土壤环境中,钢级越高,外加电位越负,波动应力比越低,管线钢应力腐蚀开裂的敏感性越强。

In order to effectively prevent and control the stress corrosion cracking of high strength pipeline steel in near-neutral p H soil environment, the stress corrosion cracking sensitivity test of X70 and X80 pipeline steel in near-neutral p H soil environment was conducted by adopting slow tensile test, electrochemical test, pressure fluctuation test and so on.Compared the stress corrosion cracking sensitivity index and electrochemical test results of X70 and X80 pipeline steel under different applied potential, selected three stress ratio, and analyzed the pressure fluctuation law of X80 pipeline steel in near-neutral p H soil environment. The results indicated that in near-neutral p H soil environment, the higher the steel grade,more negative the applied potential, the lower the stress ratio fluctuation, the stronger of the pipeline steel stress corrosion cracking sensitivity.