模拟杂散电流干扰对阴极保护下X65钢腐蚀行为的影响研究

Study on the Corrosion Behavior of X65 Steel Under Cathodic Protection Influenced by Simulated Stray Current Interference

地铁列车系统运行过程会泄漏杂散电流,造成附近埋地金属电位波动,并使阴极保护效果减弱或失效,最终导致埋地金属因腐蚀而失效。以常用的管线钢X65钢为研究对象,在实验室搭建杂散电流腐蚀模拟试验装置,进行杂散电流干扰电位±1,±2,±4 V持续4 d及杂散电流干扰电位为±2 V并持续1,2,4,8 d的2组腐蚀模拟试验,研究杂散电流干扰下受阴极保护的X65钢的腐蚀行为规律。结果表明:杂散电流干扰电位达到+2 V以上时,X65钢的腐蚀速率会急剧增大;正向杂散电流干扰会使X65钢试样发生点蚀再演变为均匀腐蚀,并在两者间循环交替,腐蚀产物成分为Fe_(2)O_(3);负向杂散电流干扰对X65钢试样存在腐蚀影响,影响作用较为轻微。

The operation of the subway train system can leak stray currents,causing fluctuations in the potential of nearby buried metal,weakening or even failing the cathodic protection effect,and ultimately leading to the failure of buried metal due to corrosion.In this paper,taking the commonly used pipeline steel X65 steel as the research object,and a stray current corrosion simulation test device was built in the laboratory.Two sets of corrosion simulation tests were conducted to study the corrosion behavior law of X65 steel subjected to cathodic protection under stray current interference,with stray current interference potentials of±1,±2 and±4 V for 4 d,and stray current interference potentials of±2 V for 1,2,4 and 8 d.The research results showed that when the stray current interference potential reached+2 V or more,the corrosion rate of X65 steel increased sharply.The pitting corrosion of X65 steel sample would be changed into uniform corrosion by the forward stray current interference,and the cycle of pitting corrosion would alternate between the two,with the corrosion product composition of Fe_(2)O_(3).Nega tive stray current interference had a corrosive effect on the X65 steel samples,but the effect was relatively minor.