辽河油田土壤中温度对高强度管线钢腐蚀行为的影响

Effects of Temperature on Corrosion Behavior of High Strength Pipeline Steel in Liaohe Oilfield Soil

为了探索辽河油田土壤中温度对高强度管线钢腐蚀行为的影响及规律，采用循环极化、动电位极化、交流阻抗等电化学测试方法,并结合试样表面观察手段进行了相关研究。结果表明：辽河油田土壤温度为0-15℃时。X80管线钢腐蚀表现为钝化型腐蚀，试样的腐蚀速率增大的趋势较为缓慢；当温度为25～45℃时，X80钢转变为活性溶解型腐蚀，金属腐蚀速率逐渐增大；随着温度的升高，X80钢的腐蚀现象越发严重，腐蚀形貌也由很少的腐蚀坑逐渐转化成为大面积腐蚀，金属的耐腐蚀能力降低；温度在15～25℃区域内，试样极化电阻变化显著，腐蚀电流密度大幅度增加．X80钢在该体系中最为敏感，此温度区域对X80钢腐蚀行为的影响最大。

Effects of temperature on corrosion behavior of the high strength pipeline steel in Liaohe oilfield soil were investigated by electrochemical testing method,including cyclic polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS) and microscopic observation of corrosion morphology as well.Results showed that when the soil temperature in Liaohe oilfield was 0~15 ℃,the corrosion behavior of X80 pipeline steel was a kind of passivated corrosion,and the change of corrosion rate of the sample was not obvious,only increasing very slowly.When the temperature was 25~45 ℃,the corrosion of the X80 steel was changed into active dissolution-type corrosion and the corrosion rate was increased gradually.With the increase of temperature,the corrosion of X80 steel became more serious and serious,and the corrosion morphology was also transformed gradually from little corrosion pits into the large corrosion area,therefore the corrosion resistance of the specimen was decreased.As the temperature was 15-25 ℃,the polarization resistance of the specimen changed significantly and the corrosion current density was increased greatly.X80 steel was the most sensitive in this system and the influence of temperature on the corrosion behavior of X80 steel was the most.