| 摘要 |
PROBLEM TO BE SOLVED: To easily and stably improve the magnetic characteristic at a low cost by controlling the hot-rolling of a slab of a specified composition consisting of C, Si, Mn, Al, N, S, Se and Fe the annealing of a hot-rolled sheet to realize a specified thickness and a specified grain size of W17/50, B8 (T). SOLUTION: A slab having the composition consisting of, by weight, 0.02-0.15% C, 2.5-4.0% Si, 0.02-0.20% Mn, 0.015-0.065 Sol. Al, 0.0030-0.0150% N, 0.005-0.040% one or more kinds of S and Se, and 0.003-0.3% one or more kinds of Sb, Sn, Cu, Mo and B as necessary, and the balance substantially Fe, is heated to 1320-1490 deg.C with the heating speed of 5 deg.C/second from 1200 deg.C, and hot-rolled. After the hot-rolled sheet is annealed at 900-1100 deg.C, the cold- rolling, decarburizing annealing, the final finish-annealing and the final finish- coating are executed. A unidirectional magnetic steel plate of 0.20-0.55 mm in product thickness, 1.5-5.5 mm in mean grain size, and to satisfy the inequalities of 0.5884l<1.9154> X<t> <=W17/50 (W/kg)<=0.7558e, 1.80<=B8(T)<=1.88 (where, (t) is the thickness mm) can be obtained. |
