PURPOSE: To facilitate installation for an existing line and regulation by disposing an investigating magnetic field generating part and a leakage magnetism detecting part on the same side of a running steel strip to be inspected.
CONSTITUTION: A magnetic flux coming from one magnetic pole 31a (N pole) of an investigating magnetic field generating part 3 is transmitted through the inside and the surface of a steel strip 100 running in proximity to an opening K and then reaches the other magnetic pole 31b (S pole). When a defective part exists in the surface or the inside of the steel strip 100, the magnetic flux leaks outside the steel strip 100 from this defective part. A leakage magnetism detecting part 4 is provided at a position located midway between the two magnetic poles 31a and 31b and coinciding virtually with the plane of the opening and detects a leakage magnetism from the steel strip 100. Since the detecting part 4 is provided on the same side as the magnetic field generating part 3 in relation to the inside of a flaw-detecting unit 1, that is, to the steel strip 100, it can be installed in proximity to the running steel strip 100 in a conveying line irrespective of a construction on the opposite side of the steel strip 100. According to this constitution, the installation and regulation can be facilitated.
MASUNO YASUHIKO
HIMENO MAKOTO
HIRAMATSU TERUO
MASUTANI MORIHIRO
ISHIMARU SEIJI
SYST HIGHTECH KK