Defect inspection device of steel plate

摘要

Provided is a defect inspection device of a steel plate. The defect inspection device according to the present invention includes a plurality of inspection units arranged in a width direction of the steel plate, wherein each of the plurality of inspection units includes a first magnetized pole and a second magnetized pole corresponding to each other. Also, the inspection unit includes: a magnetizing part generating a magnetic flux for magnetizing the steel plate in a direction inclined at a predetermined angle with respect to a rolling direction through the first magnetized pole and the second magnetized pole; and a detection part detecting a leakage flux that leaks due to defects existing in or on the steel plate by using the flux generated by the magnetizing part. Thus, the defects may be correctly detected through the defect inspection device.

主权项

1. A defect inspection device for inspecting defects in a steel plate, the defect inspection device comprising:
a plurality of upper and lower inspection units arranged in a width direction of the steel plate, the upper inspection units being disposed on an upper portion of the steel plate and the lower inspection units being disposed on a lower portion of the steel plate, wherein each of the inspection units includes:
a magnetizer including a first magnetized pole and a second magnetized pole corresponding to each other, and generating magnetic flux for magnetizing the steel plate in a direction inclined at a predetermined angle with respect to a rolling direction of the steel plate;a detector detecting a leakage magnetic flux leaked due to defects present in an interior portion or a surface of the steel plate, using the magnetic flux generated by the magnetizer; anda defect detection unit detecting a defect position in a thickness direction of the steel plate, based on a phase and a magnitude of a signal measured by each of the upper inspection units and lower inspection units, the defect detection unit detecting defects using a defects function DF calculated according to the following formula: DF=f(ΔM, A, S, Wf, L), where DF denotes a defect function, ΔM denotes a difference in magnitudes of two output signals, A denotes an area of the output signal, S denotes a slope of a straight line formed by connecting a maximum value and a minimum value of the output signal, Wf denotes a defect type, and L denotes a value for compensating an interval between the detector and the steel plate.