X80钢在NS4模拟土壤溶液中的应力腐蚀行为

Stress Corrosion Behavior of X80 Steel in NS4 Simulated Soil Solution

为了更好地研究管线钢在土壤溶液中的腐蚀机理,为其防腐蚀措施的制订提供理论依据,采用四点弯曲法,结合动电位极化和电化学交流阻抗等电化学测试技术研究了近中性模拟土壤溶液中应力、温度以及主要离子浓度等因素对X80钢应力腐蚀行为的影响。结果表明:在NS4溶液中,应力变化对于Ecorr的影响很小,其仅在15 m V内波动;温度对腐蚀速率的影响呈现规律性变化,即温度升高,X80钢的腐蚀速率增大;外加应力存在时,随Cl-浓度的增加,其自腐蚀电位Ecorr和腐蚀速率变化较大,均比无应力时的高;在较低HCO3-存在的条件下,HCO3-有促进腐蚀加剧的作用。

In order to better study the corrosion mechanism of pipeline steel in soil solution and provide a theoretical basis for establishing the anti-corrosion measures,the effects of the stress,temperature and main ion concentration on the stress corrosion behavior of X80 steel in near-neutral simulated soil solution were studied by four-point bending method,potentiodynamic polarization and electrochemical impedance spectroscopy.Results showed that in NS4 solution,the effect of stress change on Ecorrwas very small,which fluctuated only in 15 m V.The effect of temperature on corrosion rate presented a regular raw,namely that the corrosion rate of X80 steel increased with the increase of temperature.In addition,the self-corrosion potential Ecorrand corrosion rate changed greatly with the increase of Cl-ion concentration in the presence of applied stress,both of which were higher than those without stress.In the presence of few HCO3-ions,the corrosion was accelerated by HCO3-.