Patent ID: 11965856
Assignee: NIPPON STEEL CORPORATION
Field: Measurement (Instruments)
Classification: CPC G  B | IPC B  G

Claim 14:
15. A device for detecting a metal residue present in an electric-resistance-welded steel pipe, the device comprising:
an exciting coil into which the electric-resistance-welded steel pipe relatively moving in a longitudinal direction is inserted and which magnetizes the electric-resistance-welded steel pipe using a direct current at a field intensity capable of magnetizing the electric-resistance-welded steel pipe and the metal residue up to a magnetic saturation state;
a detecting coil into which the electric-resistance-welded steel pipe relatively moving in the longitudinal direction is inserted and which detects and outputs an induced electromotive force generated by a change in a magnetic flux caused by direct-current magnetization by the exciting coil; and
a detector for detecting the metal residue present in the electric-resistance-welded steel pipe on the basis of an output signal of the detecting coil.