Eddy current flaw detection probe

摘要

An insertion type eddy current flaw detection probe capable of more accurately detecting flaws in magnetic tubes is provided. A method for inspecting magnetic tubes for flaws with high accuracy is also provided. A eddy current flaw detection probe contains a cylindrical yoke (1), a plurality of detection coils (5) disposed around the central portion of the cylindrical yoke in the direction of a cylindrical axis thereof, first and second inner excitation coils (6) disposed on both sides of the plurality of detection coils in the direction of the cylindrical axis, and first and second permanent magnets (3, 4) disposed around the yoke on both sides of the first and second excitation coils in the direction of the cylindrical axis so that the direction of magnetizations thereof are parallel to the radial direction of the yoke and magnetic poles on the cylindrical yoke side thereof are different from each other.

主权项

1. An eddy current flaw detection probe, comprising:
a cylindrical yoke; a plurality of detection coils disposed around the central portion of the cylindrical yoke in the direction of a cylindrical axis thereof; first and second inner excitation coils disposed on both sides of the plurality of detection coils in the direction of the cylindrical axis, each of the first and second inner excitation coils inducing eddy current; first and second permanent magnets disposed around the yoke on both sides of the first and second excitation coils in the direction of the cylindrical axis, the direction of magnetizations thereof being parallel to the radial direction of the yoke, magnetic poles on the cylindrical yoke side thereof being different from each other; and wherein a signal applied to the excitation coils is also applied to the detection coils and the first and second excitation coils induce eddy current flowing in an opposite direction of eddy current induced by the plurality of the detection coils.