Defect measurement method, defect measurement device, and testing probe
AssigneeSumitomo Chemical Company, Limited
InventorsToyokazu Tada, Hidehiko Suetsugu
Life of this patent
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Abstract
The present invention quickly carries out quantitative evaluation of a defect of a magnetic member. An inspection probe (100), which includes: a third magnet (4) polarized in a direction intersecting a counter surface facing a magnetic member; a Hall element (11) that detects a density of a magnetic flux passing through the third magnet (4) and the magnetic member, is used to apply, to an output signal from the Hall element (11), an evaluation algorithm which is selected according to whether a defective surface is a front surface or a back surface.
Claims14
A method of measuring a defect of a magnetic member, comprising the steps of:
- (A) measuring an output from a magnetic sensor with use of an inspection probe including a magnet, the magnetic sensor which is provided on a magnetic circuit formed by the magnet and the magnetic member and which detects a density of a magnetic flux flowing through the magnetic circuit, and an excitation and detection coil which excites an eddy current for an eddy current test;
- (B) judging, by the eddy current test based on the eddy current excited by the excitation and detection coil, whether the defect is (i) a front surface defect occurring to a front surface of the magnetic member, which front surface is a counter surface facing the inspection probe or (ii) a back surface defect occurring to a back surface of the magnetic member, which back surface is opposite the counter surface;
- and
- (C) quantitatively evaluating the defect of the magnetic member by applying, to an output signal from the magnetic sensor, an evaluation algorithm which is selected from evaluation algorithms set in advance for the respective ones of the front surface defect and the back surface defect and which corresponds to a result of the judging in the step (B).
A defect measuring device which measures a defect of a magnetic member, comprising:
- an inspection probe including
- a magnet,
- a magnetic sensor which is provided on a magnetic circuit formed by the magnet and the magnetic member and which detects a density of a magnetic flux flowing through the magnetic circuit, and
- an excitation and detection coil which excites an eddy current for an eddy current test;
- an eddy current flow computing section which makes a judgment, on the basis of a detection signal from the excitation and detection coil, as to whether (i) the defect is formed on a front surface of the magnetic member, which front surface is a counter surface facing the inspection probe or (ii) the defect is formed on a back surface which is opposite the counter surface;
- and
- a magnetic flux resistance computing section which is capable of quantitatively evaluating the defect of the magnetic member in accordance with an output signal from the magnetic sensor,
- the magnetic flux resistance computing section being capable of quantitatively evaluating the defect of the magnetic member by applying, to the output signal, an evaluation algorithm which is selected according to a result of the judgment made by the eddy current flow computing section.
An inspection probe which inspects a defect of a magnetic member, comprising:
- a plurality of magnets provided so as to form a Halbach array along a counter surface of the inspection probe, which counter surface faces the magnetic member;
- an excitation and detection coil which is provided at a center portion of the Halbach array of the plurality of magnets and excites an eddy current for an eddy current test;
- and
- a magnetic sensor which (i) is provided on a magnetic circuit formed by the magnetic member and a magnet, as a part of the Halbach-arrayed magnets, that is provided at an end part of the Halbach array of the plurality of magnets and (ii) detects a density of a magnetic flux flowing through the magnetic circuit.
Dependencies are inferred from the claim text.