| 摘要 |
PROBLEM TO BE SOLVED: To provide: a motor core which still has a good magnetic property with small hysteresis loss even after stress relief annealing; and a favorable manufacturing method thereof.SOLUTION: The method of manufacturing a motor core comprises: processing a non-oriented electromagnetic steel sheet into core-shaped materials, provided that the steel sheet includes 0.005 mass% of C, no more than 4 mass% of Si, 0.05-3 mass% of Mn, no more than 3 mass% of Al, no more than 0.005 mass% of N, no more than 0.2 mass% of P, no more than 0.005 mass% of S, and no more than 0.0010 mass% of Se with the balance consisting of Fe and inevitable impurities; putting the core-shaped materials together; and then performing a stress relief annealing on the core-shaped materials thus assembled. The non-oriented electromagnetic steel sheet has a crystal grain diameter of 70 μm or smaller. In manufacturing the core, the stress relief annealing is performed so that a processed portion deformed plastically has a crystal grain diameter of 100 μm or larger, and a dislocation density of 1×10mor less. |
