Magnetic Images and NDT of the Express Train Wheel Using a High Speed Scan-Type Magnetic Camera

摘要

Wheels are essential parts of an express train, as they support the train's weight, but because of the limited time available for testing and repair in the maintenance factory, the 1000 wheels of each high-speed train must be tested within 1 h. Therefore it is essential to develop a new NDT system that is able to (a) detect cracks quickly and (b) provide high crack-detection ability regardless of the state of the materials. In this paper we propose a scan-type magnetic camera to satisfy this need. We use a linearly integrated Hall sensor array (LIHaS) as a magnetic sensor to make high-speed testing possible, and we use a small, yoke-type magnetizer as the magnetic source for the magnetic camera to assure high crack-detection ability. We tested the method by examining the cracks on a sample wheel traveling at 27.5km/h.