模拟高压直流对X65管线钢在上海地区土壤中的腐蚀影响研究

Study of the Effects of Simulation High Voltage Direct Current on the Corrosion of X65 Pipeline Steel in Shanghai Soil

为了研究高压直流接地极对管道的腐蚀影响,通过室内模拟实验考察了X65管线钢在上海地区土壤的直流干扰电压下管线钢的腐蚀行为及腐蚀电流密度变化规律。结果表明:在1.0,5.0,15.0 V的干扰电压下,腐蚀电流密度均呈现出先下降后迅速趋于稳定状态的趋势;发现X65管线钢在-0.2,0.3,1.0,5.0,15.0 V的干扰电压下的腐蚀速率与干扰电压呈正相关关系;分析了高压直流干扰下试样失重腐蚀速率与腐蚀电流密度理论计算值之间的相关性,结果显示:腐蚀速率实际测试值和电流密度计算理论值误差较小,腐蚀反应符合Faraday定律。最后,根据模拟实验结果,对上海地区土壤中高压直流干扰下管道的腐蚀风险安全边界值进行推算,可用于上海地区管道腐蚀的风险识别及预测。

In order to study the effects of high voltage direct current(HVDC)grounding pole on the corrosion of pipelines,the corrosion behavior and the variation regularity of corrosion current density of X65 pipeline steel in Shanghai soil with direct current interference voltage were studied through laboratory simulation experiments.Result showed that under the interference voltages of 1.0,5.0 and 15.0 V,all the corresponding corrosion current densities decreased first and then became stable rapidly.In addition,it was found that the corrosion rate of X65 pipeline steel under the interference voltage of-0.2,0.3,1.0,5.0,15.0 V was positively correlated with the interference voltage.The correlation between the weightless corrosion rate of the sample and the theoretical calculation value of corrosion current density under high voltage direct current interference was analyzed,and the results exhibited that the deviation between the actual test value of corrosion rate and the theoretical value of the current density calculation was small,indicating that the corrosion reaction conformed to Faraday's law.At last,according to the simulation experiment results,the safe boundary value of pipeline corrosion risk under the interference of high voltage direct current in the soil in Shanghai area was calculated,which could be used for corrosion risk identification and prediction of the pipeline in Shanghai area.