| 摘要 |
PURPOSE:To obtain a grain-oriented silicon steel sheet excellent in magnetic properties and improved in brittleness by applying hot rolling to a thin cast slab under specific conditions in a manufacturing method where a rapidly solidified thin cast slab of a steel with a specific composition free from the effect of inhibitor is used and nitriding treatment is included. CONSTITUTION:A plate of a steel having a composition consisting of, by weight, 0.025-0.100% C, 1.0-4.7% Si, 0.006-0.045% acid-soluble Al, 0.0030-0.0130% N, and the balance Fe, is cold-rolled once or is cold-rolled twice or more while process-annealed between the cold rolling stages to the final sheet thickness. In the process for subjecting the resulting steel sheet to decarburizing annealing, to the application of a separation agent at annealing, and to finish annealing for secondary recrystallization, nitriding treatment is applied to the steel sheet in any of the stages in the range after the production of the cast slab and before the initiation of secondary recrystallization in finish annealing, by that the grain-oriented silicon steel sheet can be obtained. In this method, the cast slab solidified by regulating the cooling velocity in the (alpha+gamma) two phase coexistent region at the time of casting to >=8.5 deg.C/sec is subjected to hot rolling at 900-1300 deg.C at 3-60% draft. |
