We have studied on materials evaluation for defects and damage by a scanning Hall sensor method. The Hall sensor, which is made of a semiconductor device, can detect magnetic moment, and can scan over the materials surface at room temperature. In this study, we report the advantages and technical issues to be solved of the sensing technology, and preliminary results of measurements. For steels with a notch or holes, disorder of magnetization was detected, and the test results for rails have shown that the disorder of magnetization might imply some defects.

Copyright (c) 2005 Railway Technical Research Institute