| 摘要 |
<p>A steel bar flaw detecting device capable of inspecting high-temperature steel bars at high speeds. A pre-treating unit (31), a detecting unit (32) and a post-treating unit (33) are disposed along the traveling axis of steel bars, the pre-treating unit and the post-treating unit having the same structure with dc windings (312, 332) externally wound around sleeves (311, 331) respectively. Each steel bar is magnetically saturated by a dc magnetic field, and an eddy current is generated on the surface of a steel bar by an ac winding (321) of a detection unit (12). A change in magnetic field caused by the eddy current is detected by detection windings (322, 323). An intensity of a dc magnetic field is flattened along the traveling axis of steel bars due to sleeves made of a non-magnetic material to restrict noise to be produced by a change in a dc magnetic field intensity even when steel bars are moved at high speeds.</p> |
