交流杂散电流对埋地钢质管道腐蚀危害实验

为探究交流杂散电流的影响因素及其对阴极保护系统的影响,搭建交流干扰腐蚀实验平台研究了土壤电阻率、干扰电压大小、涂层电阻率和通断时间比对交流杂散电流密度的影响;采用腐蚀试片失重法研究了交流杂散电流密度对腐蚀速率的影响以及阴极保护电位分别为-850 mV和-1 000 mV时对阴极保护系统的影响。实验结果表明:土壤电阻率、干扰电压大小、涂层电阻率和通断时间比对交流杂散电流密度具有较为显著的影响;阴极保护电位为-1 000 mV时,即使交流电流密度为20 mA/cm2,腐蚀试片也能得到有效保护。因此,埋地管道应采用绝缘性能好的防腐涂层,规划合理的铺设路线,并在运行过程中采取强制电流阴极保护系统,设置合理的阴极保护电位。

Experimental Research on AC Stray Current Corrosion Hazard of Buried Steel Pipeline

In order to study the influence factors of AC stray current and the impact of AC stray current on the cathodic protec- tion system, an AC interference corrosion experimental platform is built to study the influence of soil resistivity, the interfering volt- age, the coating resistivity and the on-off time ratio on AC stray current. Corrosion specimens weightlessness method is used to study the influence of AC stray current density on corrosion rate and the influence of AC stray current density on cathodic protection sys- tem when the cathodic protection potential is -850 mV and -1 000 mV respectively. The experimental results show that the soil re- sistivity, the interfering voltage, the coating resistivity and the on-off time ratio of AC stray current density have a significant effect on the AC stray current density. When the cathodic protection potential is -1 000 mV, corrosion specimens can be effectively pro- tected even if the AC current density reaches 20 mA/cmL Therefore, the appropriate anticorrosive coating should be applied to bur- ied pipeline. The reasonable route should be planed. Meanwhile, the compulsory current system should be adopted and the reason- able cathodic protection potential should be set properly during the operation of pipelines.