| 摘要 |
PURPOSE: To produce a grain oriented magnetic steel sheet excellent in magnetic properties and surface characteristic, free from edge crack, and having high magnetic flux density by applying specific N addition to a steel containing specific amounts of Si, Al, V, and S and further applying specific secondary recrystallization annealing. CONSTITUTION: A steel stab, containing, by weight, 1-4% Si, 0.01-0.05% Al, 0.01-0.10% V, an <=0.01% S and further containing, if necessary, 0.008-0.08% Nb, is soaked to 1000-1270 deg.C and hot-rolled. After finishing temp. is regulated to <=850 deg.C, cold rolling and primary and secondary recrystallization annealings are done. Further, 0.01-0.04% N is added to the molten steel or the steel before a secondary recrystallization annealing temp. of 950 deg.C is reached. At this time, (ξ) represented by ξ=N-14/51V, (η) represented by η=Al-27/14ξ, and primary recrystallization annealing temp. To are regulated so that they satisfy inequalities I, II, and III. Moreover, secondary recrystallization annealing is done at (0.1 to 80) deg.C/hr temp. rise rate with or without the addition of 0.05-5.0% Sb compound to MgO for forming forsterite or at (5 to 400) deg.C/hr temp. rise rate with the addition of 0.05-5.0% B compound, etc. |
