Scan Type Magnetic Camera (Cold Rolled Steel)

Abstract

Generally, the cold rolled steel has the thick thickness, clean surface, precious size, high flatness and easy mechanical forming property. Correspondingly, it is widely used in the exterior plate of automobiles and fireproof safes, office desk, refrigerator, washing machine and kitchen utensils. However, small cracks, which are generated during manufacturing process, affect to quality deterioration of the final product. Therefore, cracks have to be inspected and evaluated on the manufacturing step, and magnetic particle testing has been used. The pre-and post-processing are necessary, and expendables such as magnetic particles have to be used continuously in the magnetic particle testing. Furthermore, the large electric power has to be used to magnetize the specimen.

A method, which can detect and evaluate cracks on a cold rolled steel, without expendables such as magnetic particles, without pre-and post-processing, with smaller electric power than magnetic particle testing method, will be proposed in this research. That is, cracks on a specimen were detected and evaluated by using a scan type magnetic camera, which uses a linearly integrated Hall sensor array (hereafter, LIHaS) as a magnetic source.