| 摘要 |
PROBLEM TO BE SOLVED: To obtain a nonoriented silicon steel sheet excellent in magnetic properties, at the time of producing a high silicon steel sheet having a specified compsn., by regulating the content of S to a specified range in the process of refining molten steel and thereafter adding rare earth elements and decarburizing flux thereto. SOLUTION: At the time of refining molten steel in the production of high silicon steel, the concn. of S is regulated to 0.002 to 0.005 wt.%, and after that, rare earth elements and decarburizing flux such as limestone are added respectively by the amounts shown by the following inequalities: 0.01<R<=0.1 (R denotes the amt. kg of rare earth elements to be added per ton of the molten steel) and 50R<=CF<=2.5+50R (CF denotes the amt. of the decarburizing flux to be added per ton of the molten steel). The nonoriented silicon steel sheet having a compsn. contg., by weight, <=0.01% C, <=4.5% Si, <=2.0% Mn, 0.2 to 2.0% Al and 0.0005 to 0.01% rare earth elements, in which, as for rare earth element-contg. inclusions of 0.5 to 2 μm size in the steel, >=20% by the ratio of the number is composed of rhombic crystals RemS2 (Rem denotes rare earth elements) and excellent in magnetic properties can be obtd. |
