| 摘要 |
PURPOSE:To improve the yield of manufacturing a rare earth element permanent magnet and to stabilize the quality of the magnet by magnetizing an iron-boron alloy in which the macro structure of an ingot at casting time is columnar to simplify the steps. CONSTITUTION:An alloy made of rare earth element, iron and boron in a basic structure having a columnar structure B in a macro structure of an ingot at casting time is magnetized. When a melted metal is cast from a crucible in a mold, the metal is first contacted with the wall of the mold, quickly cooled to a degree where a large number of nuclide are generated to form a chill layer A, heat is then fed to the mold, and the columnar structure B is extended perpendicularly to the wall of the mold toward the interior. When flow of the heat is further eliminated, an equi-axed structure C is presented instead of the structure B, and the metal in the mold is completely solidified. Thus, the pulverizing property is improved to largely shorten the time required for pulverizing step to remarkably improve the magnetic performance of a permanent magnet thus obtained, thereby improving the mass productivity and the stability of the quality. |
