| 摘要 |
PURPOSE:To produce a nonoriented silicon steel sheet excellent in magnetic properties by hot-rolling a silicon steel having a specific composition consisting of C, Si, Al, and Fe, winding the resulting plate at low temp., pickling the plate, and then applying specific process annealing, cold rolling, and continuous annealing to the above. CONSTITUTION:A slab of a silicon steel having a composition consisting of, by weight, <=0.0050% C, 1.0-4.0% Si, 0.1-2.0% Al, and the balance Fe with inevitable impurities is hot-rolled and wound up at <=650 deg.C. The resulting hot rolled plate is pickled, cold-rolled at 50-70% draft to an intermediate thickness, and successively process-annealed. This process annealing is carried out so that heating rate, soaking temp. T, and soaking time (t) are regulated to 40-200 deg.C/h, 750-900 deg.C, and <=20h, respectively, and also the relations in T>=-128.5logt+811.3 are satisfied. Further, the resulting intermediate cold rolled sheet is cold-rolled at 60-70% draft to the final sheet thickness. Then, the cold rolled sheet is continuously annealed at 800-1100 deg.C for 1-5min. By this method, a nonoriented silicon steel sheet reduced in iron loss and having high magnetic flux density can be obtained. |
