GB/T 38882-2020 "Non-destructive testing—Magnetic flux leakage testing method for wall thickness variation of ferromagnetic tubes" was implemented on December 1, 2020, specifying the magnetic flux leakage testing method using external magnetization. It is applicable to ferromagnetic tubes (excluding welded tubes) with an outer diameter not less than 10 mm and a wall thickness not exceeding 20 mm, covering in-line testing during manufacturing, processing, and repair, as well as automatic testing for oilfield pipes. The standard defines personnel qualifications, equipment requirements, testing procedures, and result evaluation. The testing does not require coupling agents, is fast, and easily automated. By comparing signals from reference samples, it determines whether wall thickness loss exceeds the standard, providing a standardized basis for evaluating the structural integrity and safety of tubes.