| 摘要 |
In a magnetic inspection method and apparatus of the present invention, a magnetizer (4) is provided such that a pair of magnetic poles (4a, 4b) face an object (10) to be inspected. A magnetic field is generated by the magnetizer (4) in the object (10). A magnetic sensor (7a) is situated at substantially middle point of a line connecting the magnetic poles (4a, 4b) or a line parallel to this connecting line. Shield bodies (22a, 22b, 23a, 23b) with a low coercive force are arranged on those sides of the magnetic sensor (10) which face the magnetic poles. The magnetic sensor (7a) detects a leakage magnetic flux due to an internal or surface defect of the object (10). In addition, according to the magnetic inspection apparatus of this invention, the distance (2A) between the shield bodies (22a, 22b) is 2.2 times or more, and 2.8 times or less, the distance (L) between the magnetic sensor (7a) and the object (10). Furthermore, each shield body (23a, 23b) has an L-cross section composed of a vertical portion (24a) and a horizontal portion (24b), and the width (2A) of the horizontal portion (24b) in the direction of arrangement of the magnetic poles (4a, 4b) is 0.4 time or more, and 0.6 time or less, the distance (B) between the magnetic poles.
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