| 摘要 |
PROBLEM TO BE SOLVED: To produce a nonoriented silicon steel sheet with high magnetic flux density and low iron loss by applying roughing, coiling, coil holding, and finish rolling to a continuously cast slab under respectively specified conditions in producing a nonoriented silicon steel sheet from a steel slab of specific Si con tent. SOLUTION: A steel slab having <=7.00wt.% Si content is used and hot-rolled. The resultant hot rolled plate is subjected or not subjected to hot rolled plate annealing and is cold-rolled once or cold-rolled two or more times while process- annealed between cold rolling stages to the final sheet thickness, and the resultant sheet is finish-annealed, by which a nonoriented silicon steel sheet is produced. At this time, the continuously cast slab is roughed into roughed bar of 10-70mm thickness, and, at the time of coiling this roughed bar at 900-1,150 deg.C, the bar is formed into coil shape having a bending moment of 300-1500mm radius in the center of plate thickness. After holding at 900-1,150 deg.C for 20sec to 30min, finish rolling is done. By this method, the nonoriented silicon steel sheet, improved in iron loss as well as in magnetic flux density and excellent in magnetic properties, can be obtained. |
