| 摘要 |
PURPOSE:To simplify a manufacturing process in view of realizing cost down and obtain a magnetic shield having excellent magnetic property by manufacturing a material of magnetic shield through the primary cold rolling, open coil decarbonization annealing and secondary cold rolling to a hot rolled belt sheet of low carbon steel and by executing the formation and blackening process to such material. CONSTITUTION:A raw material for magnetic shield is manufactured by executing at least the primary cold rolling, open coil decarbonization annealing and the secondary cold rolling to a hot rolled steel belt of low carbon steel. A blank is cut out from such shield by the blanking. After the secondary cold rolling, the material is sufficiently hardened. In this condition, the shield structure is molded through bending and point welding, etc. Thereafter, the blackening process (for example, heated for 15min at 575 deg.C) is executed. During such process, distortion is eliminated by the recrystallization and growth of crystal particles simultaneously with the blackening and the magnetic characteristic can also be improved. Thereby, the shield having the crystal grain size of ASTM No.7-9 and specific permeability (0.35Oe) of 700 or more can be obtained. |
