US 12,306,135 B2
Sensitivity calibration method, inspection device, and magnetic sensor group
Yasuhiro Matsufuji, Tokyo (JP); and Takahiro Koshihara, Tokyo (JP)
Assigned to JFE STEEL CORPORATION, Tokyo (JP)
Appl. No. 18/003,316
Filed by JFE STEEL CORPORATION, Tokyo (JP)
PCT Filed Jun. 25, 2021, PCT No. PCT/JP2021/024235
§ 371(c)(1), (2) Date Dec. 26, 2022,
PCT Pub. No. WO2022/004613, PCT Pub. Date Jan. 6, 2022.
Claims priority of application No. 2020-115939 (JP), filed on Jul. 3, 2020.
Prior Publication US 2023/0258598 A1, Aug. 17, 2023
Int. Cl. G01N 27/83 (2006.01); G01N 33/2045 (2019.01); G01R 33/00 (2006.01)
CPC G01N 27/83 (2013.01) [G01N 33/2045 (2019.01); G01R 33/0017 (2013.01); G01R 33/0023 (2013.01); G01R 33/0035 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A sensitivity calibration method of an inspection device performing an on-line inspection, the inspection device measuring leakage of flux of a steel sheet connected by a welded portion while passing the steel sheet in the on-line inspection, the inspection device comprising multiple magnetic sensors respectively arranged near wiring for calibration for passing an alternating current for calibration, wherein
each of the multiple magnetic sensors is connected in series to each of multiple gain-adjustable amplifiers and each of a bandpass filters extracting a frequency band to be detected,
the inspection device, while the steel sheet is not passed, obtains a first output value of each of multiple magnetic sensors in advance by applying an alternating current to the wiring for calibration and inputting a pulse signal determining a frequency band corresponding to an alternating magnetic field generated by applying an alternating current to the bandpass filter,
before a welding portion of the steel sheet passes a position of the magnetic sensors in a sheet passing direction during passing the steel sheet, the inspection device retracts the multiple magnetic sensors from a detection position of leakage flux of the steel sheet, starts applying an alternating current to the wiring for calibration, inputting the pulse signal determining a frequency band corresponding to the alternating magnetic field generated by applying an alternating current to the bandpass filter, and obtains a second output value of each of the multiple magnetic sensors, and
after the welding position passes the position of the magnetic sensors during passing the steel sheet, the inspection device displaces the multiple magnetic sensors to the detection position, inputting the pulse signal corresponding to a certain pitch of an area where magnetic domain refining has been performed in the sheet passing direction of the steel sheet, and corrects a measurement value measured by each of the multiple magnetic sensors based on the first output value and the second output value.