Research On The Low Frequency Magnetic Flux Leakage Eddy Current Testing Method Of Rail Defects

In recent years, China railway transportation implemented the technology policy of high-speed and heavy-carriage. The working conditions of the rail which is an important infrastructure are worsening day by day. Therefore, to ensure the safety of rail transport, the quality requirements of rail are higher and higher. Meanwhile, our rail technical standards today are still in a low level. Rail equipment of domestic manufacturers improves slowly. There is a certain gap between domestic rail in the metallurgical quality, bar-system accuracy, testing means and the international level. So, the quality of rail factory testing is particularly important.At present, the testing means of rail manufacturers are still rather backward, and can not completely meet the testing requirements of defects. Accordingly, the magnetic flux leakage theory is combined with electromagnetic eddy current theory. The testing technology is summarized according to the related nondestructive testing technology. According to the theory of low-frequency flux leakage eddy current testing technology, a new type of incentive testing device which is called rail low-frequency flux leakage eddy current testing incentive testing device has been researched and designed. It is a very important component in the testing system. When testing the internal defects rail using the incentive testing device, flux leakage theory intensity has been simulated and analyzed using the powerful electromagnetic analysis features of ANSYS according to the basic electromagnetic theory of finite element electromagnetic. The results showed that the low-frequency flux leakage eddy current testing technology completely adapted to testing rail internal defects, and the new type incentive testing device also can completely test out the rail internal defects. Finally we optimized the related parameters of the new type incentive testing device, and finished the preliminary design of the new type incentive testing device.In this paper, the theory of low frequency magnetic flux leakage eddy current testing technology has been studied and analyzed according to the related nondestructive testing technology. Also the theory to rail internal defects testing has been introduced. And the problem of rail internal defects testing was successfully solved first theoretically.