| 摘要 |
PURPOSE:To stably manufacture a high grade nondirectinal electromagnetic steel plate having a low iron loss and good magnetic flux density at S8 equivalency and S7 equivalency by a method wherein both intermediate annealing and finishing annealing are done at a high temperature and a short time and under nonoxidation and nondecarburization atmosphere. CONSTITUTION:Two times of cold rolling is applied by doing continuous annealing between the cold rolling processes to a hot rolled plate for electromagnetic steel plate including Si:2.5% or more, Al:0.5% or more, Si+Al:3.0%-5.0%, Mn: 0.1-1.0% and having C of 0.0050% or less, S of 0.0050% or less, and N of 0.0040% or less and final plate thickness is made. Next, finishing annealing is done. The above intermediate annealing is done under nonoxidation and nondecarburization atmosphere at 950-1,100 deg.C for 20sec or more and 120sec or less for an intermediate cold rolled plate having a range of 35-45% of final cold rolled draft rate. Finishing annealing is done by increasing temperature between 400-800 deg.C at a temperature rising speed of 10 deg.C/sec. or more and short time annealing for 3-60sec is done under nonoxidation and nondecarburization atmosphere at 950-1,100 deg.C. |
