API 5L seamless steel pipe is characterized by large diameter and wall thickness, so according to this characteristic, combined with the function of ultrasonic eddy current detection and internal and external surface detection, the "blind spot" detection is realized. Through the "positive combination of steel tube rotating detection probes", not only the problem of heading detection is solved, but also the problem of reducing space occupation is solved.


Therefore, magnetic leakage test or hydraulic test are usually used to detect seamless steel tubes at home and abroad. In China, the production of seamless magnetic flux leakage testing equipment does not have good performance. After use, need to import. Imported magnetic flux leakage testing equipment is expensive, which is unacceptable to most domestic enterprises, and the hydraulic test is inefficient and labor intensive. Especially when the operator's responsibility is not high, the hydraulic test is only nominal. Obviously, the realization of large-caliber seamless steel tube inspection has become an urgent problem to be solved in the metallurgical steel tube industry.


The ultrasonic detection of flume consists of steel screw and ultrasonic probe. The thickness of the coupling layer is fully coupled to the bottom of the steel tube to ensure the same thickness. However, due to the main surface defects and sub-surface defects, there are blind spots that can not be detected. Using spiral type, 12m long steel pipe needs 30m space and other defects, affecting the selection and promotion of steel inspection methods.


The circumferential surface of steel pipe surface is measured by DC eddy current. When the direct eddy current test is used, the larger the diameter of the detected pipe, the larger the coil area of the circle and the lower the signal-to-noise ratio. Therefore, the standard of eddy current testing adopts cross-flow eddy current testing, and its external economic scale should not exceed 140 mm. In addition, it is difficult to detect seamless tubes by type, magnetization and demagnetization.