Along with the high-speed development of oil-gas industry, the corrosion of pipes and pipelines used for transporting oil and gas is more and more serious. Also is the menace of them. The cost of corrosion is enormous, including shuttling down of the factory, loss of products and materials, power waste, etc. Corrosion can even result in pipeline leakage accident, polluting environment, threatening people's safety. So it is necessary to inspect the pipeline corrosion condition to avoid pipeline a...