| 摘要 |
PURPOSE:To produce a high magnetic flux density grain-oriented silicon steel sheet low in core loss by executing finish annealing under specified conditions at the time of producing a high magnetic flux density grain-oriented silicon steel sheet from a silicon steel slab having a specified componental compsn. CONSTITUTION:A high magnetic flux density grain-oriented steel sheet is produced from a silicon steel slab having a compsn. contg., by weight, 0.020 to 0.075% C, 2.5 to 5.0% Si, 0.05 to 0.45% Mn, <=0.15% of one or more kinds of S and Se, 0.010 to 0.050% acid soluble Al, 0.0035 to 0.012% N, 0.02 to 0.15% Sn, 0.03 to 0.20% Cr, and the balance Fe with ineviatable impurities. At this time, finish annealing is executed so that the temp. rising rate at 900 to 1200 deg.C in the temp. rising stage is regulated to the range of 3 to 35 deg.C/hr, a gaseous mixture of N2 and H2 is used as the atmospheric gas therein, the relationship of -1.2R+46<=N<=-2.7R+118 is satisfied between the ratio N(%) in the gaseous N and R, and the oxidizing potential PH2O/PH2 in the annealing atmosphere is regulated to <=0.020. |
