| 摘要 |
PURPOSE:To eliminate the necessity for a magnetic annealing process after molding and obtain an internal magnetic shield provided with good mechanical strength and blackening film quality while fully holding a magnetic shielding effect, by fixing N as a compound of AlN to a cold rolled steel belt, in composition mainly composed with Fe and contained with C, Mn, SolAl, N and impurities, press molding the cold rolled steel belt and then applying surface blackening treatment. CONSTITUTION:An ultra-low carbon steel belt, fixed as a compound of AlN by precipitation treatment, in composition mainly composed with Fe and contained with 0.01wt% C or less, 0.1-0.3wt% Mn, Al and N, where Al and N are 0.01- 0.06wt% and 0.02-0.1wt% respectively in a solid solution state, is press molded and then heated for 10-30min in a wet atmosphere at 550-600 deg.C, thus surface blackening treatment is applied to obtain specific permeability at least 600 in crystal grain size ASTM8. A crystal grain is not formed large in the crystal grain size ASTM8, and a magnetic shield, with good press molding and a fine blackening film also with sufficient mechanical strength, can be obtained. |
