| 摘要 |
PURPOSE: To produce a magnetic shield material excellent in magnetic properties by a simple process by subjecting the continuously cast slab of a dead soft steel to hot rolling and annealing under specified temp. conditions, thereafter working it into a finah sheet thickness by cold rolling including process annealing and furthermore executing final annealing. CONSTITUTION: The continuously cast slab of a dead soft steel contg., by weight, <0.005% C, <0.03% Si, 0.23 to 0.40% Mn, <0.003% sol.Al and <0.010% S is heated to 1000 to 1200 deg.C and is subjected to hot rolling into a hot rolled sheet. The hot rolling is finished at 730 to 860 C, and this hot rolled sheet is coiled a round a coil at 400 to 620 deg.C. Next, this hot rolled sheet is subjected to pickling treatment to melt away oxidized scales on the surface, and after that, it is subjected to batch annealing or continuous annealing in the temp. range of 720 to 900 deg.C to grow crystalline grains and to remove away working strains caused by the hot rolling. Next, it is formed into a thin steel sheet having a final sheet thickness by primary cold rolling including process annealing and secondary cold rolling at 40 to 75% draft, is subjected to final annealing by batch annealing or continuous annealing at 640 to 850 deg.C according to necessary and is thereafter subjected to blackening treatment. |
