电焊动火过程中杂散电流对长输管道的腐蚀研究

采用杂散电流测量仪监测电焊动火过程杂散电流的变化情况，研究了电焊动火过程中管道及周围土壤中的杂散电流分布规律。结果表明，管道中的杂散电流由电焊点向管道两侧流动，杂散电流并不稳定，其变化范围很大，最大值与最小值相差几十倍；管中杂散电流随着离电焊点距离的增大逐渐减小，随着电焊机台数的增加逐渐增大，随着管道管径的增大，逐渐增大；同时在焊接过程中，土壤中的电位梯度相应增大，并随着离管道距离的增大逐渐减小。

Study on Stray Current Corrosion of Long Pipeline during Welding

Stray current change during welding work was monitored by stray current measurement instrument , stray current distribution of pipelines and soils around pipelines during welding was studied. The results indicate that the stray current of pipeline flows from the welding point to both sides of the pipeline. The stray current is not steady and its change range is very large. The stray current of pipeline gradually decreases along with increase of distance to the welding point, gradually increases along with increase of welding machine numbers and pipe diameter ,and at the same time electric gradient in soil appropriately increases during welding and it gradually decreases along with increase of distance to the pipeline.