| 摘要 |
PURPOSE:To obtain a magnet showing a high magnetic characteristic when outer-peripheral magnetization is applied thereto by a method wherein an axisymmetric billet made of an Mn-Al-C alloy for a magnet is subjected to compression machining in the direction of the axis thereof and simultaneously the outer peripheral surface of the billet is formed to be indented. CONSTITUTION:An axisymmetric billet made of an Mn-Al-C alloy for a magnet is subjected to compression machining in the direction of the axis thereof at a temperature of 530 to 830 deg.C so that the outer peripheral surface thereof is formed to be indented, and thereby a magnet showing a high magnetic characteristic when outer-peripheral magnetization is applied thereto can be obtained. The compression machining is not always needed to be successive, but it may be divided into a plurality of processes. In the state after the compression machining, in comparison with the state before the machining, the diameter of the columnar billet 1 is extended with the advance of the compression machining, and part of the outer peripheral surface thereof turns to be in contact with a die body 2. With the compression machining advanced further, the outer peripheral surface of the billet 1 is made to contact substantially with the inner surface of the die body 2. |
