氯离子和直流电流密度对X65钢的腐蚀研究

Corrosion of X65 Steel under Influence of Cl-and Direct Current Density

目的通过浸泡实验和腐蚀图像表征方法研究氯离子和直流杂散电流共同作用下X65钢的腐蚀特征。方法通过浸泡实验,在不同氯离子浓度和直流电流密度的共同作用下,通过失重法计算X65钢的均匀腐蚀速率。通过三维显微镜对浸泡后的腐蚀形貌进行观察,确定其主要腐蚀形态和发展规律。结果在不同的氯离子浓度下,X65钢的均匀腐蚀速率基本不变,误差主要来自于腐蚀产物清洗不彻底和环氧树脂吸水的差异性。而腐蚀速率与直流电流密度成正比,氯离子主要作用是使试片形成不同的局部腐蚀特征,破坏了试片表面的均匀腐蚀,而加剧了局部腐蚀,但对整体的腐蚀速率基本没有影响。结论引起管道腐蚀失重的主要因素为流出管道的直流电流密度,而与所处环境无关。低氯离子浓度是导致局部腐蚀的主要原因,随着氯离子浓度的增大,腐蚀逐渐向均匀腐蚀转变。直流电流密度造成的腐蚀以均匀腐蚀为主。

The work aims to study corrosion characteristics of X65 steel by immersion experiment and corrosion image re- presentation under the combined action of CY and DC stray density. Uniform corrosion rate of X65 steel was calculated in loss weight method and by immersion experiment under the influence of C1 and direct current density. Corrosion morphology after immersion was observed with three-dimensional microscope to verify main corrosion morphology and its law of development. Provided with different C1 concentration, the uniform corrosion rate of X65 steel almost remained unchanged and the error was mainly due to insufficient cleaning of corrosion products and water absorption difference of epoxy resin. Corrosion rate was proportional to direct current density, and main effect of C1- was to produce different local corrosion characteristics on the spe- cimen, thus damaging uniform corrosion on specimen and intensifying local corrosion, but having no effect on overall corrosion rate. Direct current density outflowing from pipe, rather than the environment conditions, from pipe is the main cause of pipe corrosion weight loss. Low Cl concentration is the main cause of local corrosion of X65 steel. With the increase of C1- concen- tration, the corrosion form gradually turns into uniform corrosion. Corrosion caused by direct current density is mainly uniform corrosion.