Eddy current flaw detection device and eddy current flaw detection method

An eddy current flaw detection method comprising:

• an exciter/detector disposing step of disposing an exciter and a detector near a tested object and on the same side of the tested object so that a magnetic field penetrates the tested object and exists on a back surface of the tested object due to skin effect;
• a backside body disposing step of disposing a backside body made of ferromagnetic material, at a position where the magnetic field exists to enhance a magnetic flux in the tested object and near the tested object at an opposite side of the exciter/detector sandwiching the tested object therebetween;
• an excitation step, after the exciter/detector disposing step and the backside body disposing step, of inducing eddy current in the tested object by the exciter/detector;
• and
• a detection step of detecting, by the exciter/detector, a change of reactive magnetic field generated by the eddy current.

An eddy current flaw detection device comprising:

• an exciter configured to induce eddy current in a tested object so that a magnetic field penetrates the tested object and exists on a back surface of the tested object due to skin effect,
• a detector configured to detect a change in a reactive magnetic field generated by the eddy current, the detector and the exciter being located on the same side of the tested object,
• a backside body made of ferromagnetic material disposed on an opposite side of the exciter and the detector sandwiching the tested object therebetween, the backside body being disposed at a position where the magnetic field exists to enhance a magnetic flux in the tested object, and
• a cover made of ferromagnetic material covering at least some part of surroundings of the exciter and the detector, the at least some part of the surroundings of the exciter and the detector being not facing the tested object.