PRODUCTION OF GRAIN-ORIENTED SILICON STEEL SHEET EXCELLENT IN MAGNETIC PROPERTY AND COATING CHARACTERISTIC

Japanese Patent JP3480332

B2

PROBLEM TO BE SOLVED: To stably improve the magnetic properties of a steel sheet by a cold rolling one time method and to obtain satisfactory coating characteristic over the whole width and whole length of a strip by specifying the compsn. of an Si steel slab and executing hot rolled sheet annealing, cold rolling and decarburizing annealing.
SOLUTION: An Si steel slab contg., by weight, 0.03 to 0.12% C, 2.0 to 4.5% Si, 0.01 to 0.05% acid soluble Al and 0.004 to 0.012% N is subjected to hot rolling, is thereafter subjected to hot rolled sheet annealing at 800 to 1200°C and is subsequently subjected to pickling treatment. At this time, in the case the sheet thickness after the hot rolled sheet annealing and before cold rolling is defined as t1 (mm), and the sheet thickness after cold rolling is defined as tR (mm), the thickness of the region in which the ratio of the concn. of Si in the center part of the sheet thickness to the concn. of Si in a state before cold rolling is regulated ≤0.98 is regulated to from 0.5×t1/tR to 8×t1/tR μm from the surface to the thickness direction. In final cold rolling, the steel sheet temp. just after the outlet side of rolling rolls is regulated to 150 to 350°C for at least two times. Next decarburizing annealing is executed at a temp. rising rate of ≥5°C/sec.

Hiroaki Toda
Mineo Muraki
Michio Komatsubara

JP26104198A

December 15, 2003

September 01, 1998

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JFE Steel Corporation

C21D8/12; C22C38/00; C22C38/06; H01F1/16; (IPC1-7): C21D8/12; C22C38/00; C22C38/06; H01F1/16

JP9143637A
JP797631A
JP9143562A
JP9194942A

Kosaku Sugimura

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