不同高压直流干扰工况下X80管线钢的腐蚀行为

Corrosion Behavior of X80 Pipeline Steel under Different High Voltage DC Interference

采用自行搭建的装置对X80管线钢进行高压直流干扰腐蚀试验,并通过干扰参数监测和腐蚀形貌观察等方法,考察了在不同高压直流干扰下该钢在四川土壤中的干扰电流密度变化趋势及腐蚀规律。结果表明:电流密度在干扰初期快速增大到峰值,然后快速下降并趋于稳定,稳定值约为峰值的1/10;高压直流干扰时长(持续时间)对腐蚀速率有一定影响,腐蚀速率随着干扰时长的延长而降低;高压直流干扰的间隔时间对腐蚀速率也有明显影响,腐蚀速率随着干扰间隔时间的延长呈增大趋势,干扰间隔时间超过3h后,腐蚀速率明显增大;管道防腐蚀层缺陷面积和土壤含水率对腐蚀速率都有较大影响,当缺陷面积由6.5cm^(2)减小为0.2cm^(2)时,腐蚀速率增大了约3倍,当土壤含水率由17%增加为34.5%时,腐蚀速率增大了数十倍。

The corrosion test of X80pipeline steel was carried out by simulating high voltage direct current(HVDC)interference with a self-built device.The variation trend of interference current density and corrosion rule of the steel in Sichuan soil under different HVDC interference conditions were investigated by monitoring interference parameters and observing corrosion morphology.The results show that the current density increased rapidly to the peak value at the initial stage of interference,and then decreased rapidly and tended to be stable.The stable value was about 1/10of the peak value.The interference duration had a certain effect on the corrosion rate,and the corrosion rate decreased with the extension of the interference duration.The interval of HVDC interference also had a significant effect on the corrosion rate.The corrosion rate increased with the extension of the interference interval,and the corrosion rate increased obviously after the interference interval exceeded 3h.Both the defect area of pipeline corrosion protection layer and soil moisture had a great influence on the corrosion rate.The corrosion rate increased by about 4times When the defect area decreased from 6.5cm2 to 0.2cm2.When the soil moisture increases from 17%to 34.5%,the corrosion rate increased by tens of times.