GRAIN-ORIENTED ELECTRICAL STEEL SHEET AND MANUFACTURING METHOD FOR THE SAME

摘要

Disclosed is a method for manufacturing directional electric steel sheets. The method for manufacturing the directional electric steel sheets comprises a step of (1) manufacturing a slab consisting 2.0~4.0 wt% of Si; less than 0.085 wt% of C; 0.015~0.04 wt% of acid solubility Al; less than 0.20 wt% of Mn; less than 0.004 wt% of N; less than 0.004 wt% of S; residual Fe; and inevitable impurities; (2) reheating the slab to heat-treat precipitates in the slab; (3) cold-rolling the reheated slab after the heat-treatment with or without a annealing process; (4) first recrystallizing and annealing based on three phases of temperature increase patterns including a process of super rapid-increasing the temperature at the average temperature increase speed of more than 300°C/sec, a process of rapid-increasing the temperature at the average temperature increase speed of more than 100°C/sec which is lower than the average temperature increase speed in an initial temperature increase process after the process of super rapid increasing the temperature, and a process of increasing the temperature at the average temperature increasing speed lower than the average temperature increase speed in the super rapid temperature increasing process after the rapid temperature increasing process; (5) finally annealing the first recrystallized and annealed slab.