| 摘要 |
PROBLEM TO BE SOLVED: To provide a stable manufacturing technique of a nonoriented silicon steel sheet excellent in magnetic properties in the longitudinal direction of coil. SOLUTION: A slab, having a composition consisting of, by weight, either or both of 0.1-4.0% Si and 0.1-2.0% Mn and the balance Fe with inevitable impurities, is roughly rolled into sheet bar and then subjected to finish hot rolling at 750-1150 deg.C finishing temperature under the following conditions: the maximum value of the parameter defined by equation Z=log ε exp[32,100/(273+t)]} [where (ε) and (t) are strain rate (1/s) and rolling temperature ( deg.C), respectively] in the final pass is <16.0; and the range of fluctuations in the above parameter is <=2.0. The resultant hot rolled plate is coiled at 750 to 1050 deg.C, held for 30 sec to 60 min, uncoiled, cooled, and coiled again at <=550 deg.C. Subsequently, the steel plate is subjected to a single cold rolling stage and then finish annealed and formed into the final product, or is cold rolled two or more times while process annealed between the cold rolling stages and formed into the final product, or is further subjected to skin pass rolling at 2 to <20% and formed into the final product. |
