| 摘要 |
PURPOSE:To improve the distribution of magnetic characteristics by a method wherein a compressive processing in axial direction of a billet is performed at the prescribed temperature in such a manner that the compressive distortion of the outermost circumferential part of the billet will be made larger than that of the inside part. CONSTITUTION:Cutting and machining operations are performed on the rod obtained by extrusion-processing an Mn-Al-C alloy, and a cylindrical billet (not shown) is obtained. After a face anisotropic magnet has been formed by performing a free compressive processing on said billet 1, a cylindrical billet 1 is obtained by performing a machining work. Then, said billet 1 is inserted between a bottom force 4 and a fixing punch 2, maintained at the temperature of 530-830 deg.C, and a compressive processing is performed on the outer circumferential part only of the billet 1 using a movable punch 3. Then, after the outer circumference of the billet 1 has been machined, the outer circumference is magnetized. As a result, the magnetic characteristics in radial direction suitable for an outer circumferential multipolar magnetization can be obtained.
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