| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a low-cost grain oriented silicon steel sheet, capable of giving a steel sheet minimal in fluctuations in magnetic properties and having a high magnetic flux density by means of a low temperature slab heating even if a hot rolled plate annealing is omitted. SOLUTION: A silicon steel slab, having a composition containing, by weight, <=0.075% C, 2.5-4.5% Si, <=0.015%, independently or in combination, of S or Se, and 0.0005-0.0040% B and further containing Al, N, Sn, Cr, Mn, and Cu, is heated to <=1,280 deg.C and hot rolled, and the resultant steel plate is subjected to cold rolling at a draft of >=80%, to decarburizing annealing, to nitriding treatment, and to finish annealing, by which the grain oriented silicon steel sheet can be manufactured. In this method, at the time of hot rolling, the initial finish hot rolling temperature after roughing at >=60% cumulative draft is regulated to 900-1,100 deg.C, and also the B content of the slab and the deviation ΔF0T( deg.C), in the inner part of coil, of initial finish hot rolling temperature are controlled to values within the ranges satisfying ΔF0T<=1.25.B+50 (where B: ppm). |
