Systematic Approach to Problem Solving of Low Quality Arc Welding during Pipeline Maintenance Using ARIZ (Algorithm of Inventive Problem Solving)

Abstract

The pipelines in the oil and gas industry must be regularly checked for possible corrosion that might cause leakage of oil and gas. Magnetic flux leakage (MFL) technique is a magnetic method of nondestructive testing that is used to detect corrosion and metal loss in steel pipelines. The MFL device travels inside a pipeline to inspect the corrosion parts with a powerful magnet which is used to magnetize the pipe wall. At areas where there is corrosion or missing metal, the magnetic field leaks from the pipe wall and will be detected by magnetic sensors placed between the poles of the magnet and data is transmitted to the outside recording device for analysis. The problem occurs when it is necessary to remove the damaged segments of the pipe and replace them with the new ones by welding them to the existing pipelines. It is found that welding rod and arc column are subjected to some kind of force that causes them to deviate from the right position. In this paper, the problem of low quality arc welding during pipeline maintenance due to residual magnetic field on the pipeline caused by MFL inspection device is systematically analyzed to find the root causes and ideal solution of which internal resources are utilized, is attained by using ARIZ (in this paper, magnetic field from welding current is selected). Computer simulation using finite element method and field test are conducted and show satisfactory result for the proposed idea.