| 摘要 |
PROBLEM TO BE SOLVED: To stabilize secondary recrystallization by specifying Cu, S + Se, and Sb + Sn, respectively, and to improve iron loss characteristic by reducing the size of grains. SOLUTION: A slab, having a composition consisting of 0.025-0.075% C, 2.5-4.0% Si, 0.02-0.10% P, 0.010-0.050% acid soluble Al, 0.0040-0.0130% N, 0.007-0.020% S and/or Se, 0.05-0.5% Mn, 0.06-0.20% Sn + Sb, 0.03-0.50% Cu, and the balance Fe with inevitable impurities, is heated at <1280 deg.C and hot- rolled and then subjected to hot rolled plate annealing or cold-rolled one or more times while process-annealed between cold rolling stages. After decarburizing annealing, nitriding treatment is performed in the state where a strip is allowed to travel. Then, a separation agent at annealing, composed essentially of MgO, is applied and final finish annealing is performed. By this method, magnetic flux density is increased and the size of secondary recrystallized grains is regulated to about 10mm, and iron loss can be remarkably improved. |
