High-speed MFL method and apparatus based on orthogonal magnetisation for steel pipe

Abstract

In order to realise a fast inspection for the steel pipes in high-speed production line, a magnetic flux leakage (MFL) method based on orthogonal magnetisation was proposed for the first time, which only requires an axial linear scanning by a linear motion of pipe at a high speed as opposed to conventional helical scanning at a low speed. The feasibility conventional helical scanning at a low speed. the feasibility and practicability of the approach were verified by the practical application of a high-speed inspection apparatus thatwas invented. Meanwile, the analysis of circumferential that was invented. Meanwhile, the analysis of circumferential magnetisation characteristics and optimisation designs for magnetisers and inspection probes were conducted by finite element methods, which are helpful to the circumferential magnetiser's design. The proposed method in this paper can greatly improve test speed to meet the requirement of rapid productions and can also accomplish fast detection for the pipes for which it is difficult to have a circumferential self-rotation, such as coiled tubing and square tube.