PRODUCTION OF ENERGY CONSERVATION TYPE MULTI-FUNCTIONAL HIGH MAGNETIC FLUX DENSITY GRAIN-ORIENTED SILICON STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To obtain an energy consumption type product free from hot rolling ear cracking and having high magnetic flux density by specifying the compsn., hot rolling conditions, compositional balance, annealing conditions, oxygen coating weight after annealing, the ratio of FeO/SiO₂ or the like in a grain-oriented silicon steel sheet. ;SOLUTION: A steel slab contg., by weight, 1 to 4% Si, 0.01 to 0.05% Al, 0.01 to 0.10% V, 0.015 to 0.0200% Hf and ≤0.01% S is soaked at 1000 to 1270°C, is subjected to hot rolling finish at ≥850°C and is subjected to cold rolling, primary and secondary recrystallization annealing or the like to obtain a grain-oriented silicon steel sheet. In this process, N is added by 0.01 to 0.04%, and in the case the formula I is defined to the total N content, the inequality II is allowed to satisfy, and in the case the formula III is defined, the inequality IV is allowed to satisfy. Moreover, the primary recrystallization temp. is allowed to satisfy the condition in the inequality V. The oxygen coating weight after the annealing is regulated to 1500ppm, and the ratio of FeO/SiO in the formed oxidized film is regulated to ≤0.40. Furthermore, to 100 pts.wt. of MgO in a separation agent for annealing, the sulfides of Li, K, Bi, Na, Ba, Ca or the like are incorporated by 0.5 to 20 pts.;COPYRIGHT: (C)1997,JPO