| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for improving the magnetic properties of a grain oriented silicon steel sheet after finish annealing by properly controlling the growth of grains in a primarily crystallized sheet even under the condition that a slab heating temperature is low to the extent of the case of common steel, and also improving its coating properties. <P>SOLUTION: The steel slab having a prescribed componential composition is heated to ≤1,300°C, and is thereafter hot-rolled. After that, the steel sheet is, if required, subjected to hot rolled sheet annealing, and is then subjected to cold rolling for one time or for two or more times including process annealing so as to obtain a final sheet thickness. Next, the steel sheet is subjected to annealing for primary recrystallization and decarburization, and is then subjected to final finish annealing. In this method of producing a silicon steel sheet consisting of a series of stages above, electromagnetic stirring is performed on casting of the steel slab, and, as for the annealing for primary recrystallization and decarburization, the steel sheet is retained in the temperature range of 600 to 1,000°C for ≤120 sec, and also, the atmosphere in the residence period is controlled so that the content of hydrogen is regulated to 30 to 60 vol.%, and a dew point to 15 to 40°C, and, after that, the steel sheet is retained in the temperature range of 750 to 900°C for ≥60 sec, and the atmosphere in the residence time is controlled so that the content of hydrogen is regulated to 40 to 70 vol.%, and a dew point to 40 to 70°C. <P>COPYRIGHT: (C)2003,JPO |
