| 摘要 |
PURPOSE:To obtain a high-performance permanent magnet at a low cost by limiting the reduction ratio below the border of a specific degree of working and that above the border. CONSTITUTION:An alloy having a composition of Pr17Fe76.5B5Cu1.5 is fused in an argon atmosphere in an induction heating furnace, and then cast. The cast sample is cut into billets and ground. The individual billets are placed in a sheath of SS41, and the sheath is sealed by welding and heated. The sheath is rolled using a mill equipped with a roll. Then the reduction ratio is controlled within a low range of 10-25% when the degree of working (reduction ratio of thickness) is 40-50% or below; the reduction ratio is increased to approx. 30% when the degree of working is 40-50% or above. This remarkably improves the magnetic characteristic compared with conventional methods. Moreover, the present method provides a high magnetic characteristic even at a lower degree of working, obtaining stable high values over the wide range of degree of working. |
