| 摘要 |
PROBLEM TO BE SOLVED: To obtain a magnetic steel sheet having high machinability and a high magnetic characteristic by specifying the number of inclusions having a specific particle size or larger of the inclusions observed on the end face of steel sheet against the total number of inclusions. SOLUTION: Test pieces of a nonoriented magnetic steel sheet which contain nearly the same number (about 8,000-10,000 particles/mm2) of inclusions having particle size of >=0.1 μm, about 1 wt.% (Si+Al), about 110-130 Vickers hardness, and inclusions in various particle size distributions are examined and the test pieces are put in order based on the ratio (%) of the number per unit area of inclusions having particle sizes of >=0.1 μm to the number per unit area of inclusions having particle sizes of >=2 μm. When the number of the inclusions having particle sizes of >=2 μm exceeds the 10% of the total number of the inclusions having particle sizes of >=0.1 μm, the machinability of the magnetic steel sheet is improved. In addition, the kinds of the inclusions have no relation to the magnetic characteristic and machinability of the steel sheet. |
