| 摘要 |
PURPOSE:To obtain high magnetic flux density despite low temp. heating of a silicon steel slab by specifying the S in steel in the stage of heating a silicon steel slab and hot rolling the same, then subjecting the same to high temp. finish annealing including secondary recrystallization treatment after cold rolling and primary recrystallization annealing. CONSTITUTION:A silicon steel slab of <=0.015% C, <=4% Si, <=0.012% S, 0.020- 0.0065 acid soluble Al, and 0.0030-0.009% T.N is heated at <=1,270 deg.C, after which it is hot-rolled continuously to a hot-rolled plate. This is coiled at 700- 900 deg.C, after which it is cold-rolled at >=65% draft, and is subjected to primary recrystallization annealing in a short time. While this steel plate in the primary and secondary recrystallization region boundary part is given with a >=2 deg.C/cm temp. gradient, it is subjected to high temp. finish annealing including a treatment for growing secondary recrystallization particles. Thereby, the high magnetic flux density of about >=1.94% T B8 is obtained, but unless the content of S is limited as shown above, the generation of low magnetic flux density and the imperfect secondary recrystallization are caused in some cases, and the high magnetic flux density is not obtained stably. |
