| 摘要 |
PURPOSE:To prevent the occurrence of edge cracking of a silicon steel plate of ultrahigh silicon content in a hot rolling stage by specifying silicon content and controlling rolling conditions. CONSTITUTION:This silicon steel has 5.0-7.1wt.% silicon content and has the balance essentially iron with inevitable impurities. An ingot, a continuously cast slab, or a thin slab of this ultrahigh silicon steel is hot-rolled under the condition that width-direction central temp. Tc and edge temp. Te satisfy Tc-Te<=20 deg.C, and width-direction reduction is regulated to >=10mm. Further, it is preferable that the ingot or the slab is heated to >1100-1200 deg.C, hot-roughed at >50% cumulative reduction by reverse rolling, then reheated to <1100-1200 deg.C, and hot-finish-rolled. At the time of this hot rolling, rolling is done while regulating the time between respective passes to >10sec, and the temp. of a material to be rolled is kept at >=600 deg.C. Moreover, as a rolling mill to be used, a steckel mill in which furnace coilers are disposed in front and in rear is preferred. |
