Metal parts in the medium due to the formation of a very small gap between metal and metal, so that the gap medium in the DC state, the formation of oxygen concentration battery caused by the local corrosion known as gap corrosion. Strictly speaking, corrosion detection under pipe support is a common type of crevice corrosion. In recent years, due to the high frequency of corrosion failure accidents, serious failure consequences and no good detection means, it has attracted more and more attention.

The resistance matrix online monitoring technology developed a special pipeline magnetic adsorption probe, which were arranged on both sides of the pipe support during detection. Through the collection and analysis of the electrical impedance of the pipe body, the corrosion rate of the pipe wall under the support was obtained and the remaining wall thickness was calculated. Because of the high temperature compensation function, the technology is also suitable for high temperature pipeline.