| 摘要 |
PURPOSE:To produce a grain-oriented silicon steel sheet having low core loss and high magnetic flux density, at the time of producing a grain-oriented silicon steel sheet having a specified compsn., by prescribing the atmospheric gas of finish annealing under specified conditions. CONSTITUTION: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 0.65% Mn, <=0.15% of one or more kinds of S and Se, 0.010 to 0.050% acid soluble Al, 0.0035 to 0.0I2% N, 0.02 to 0.15% Sn, 0.03 to 0.20% Cr, and the balance Fe with inevitable impurities is subjected to hot rolling, cold rolling, decarburizing annealing; nitriding treatment and finish annealing to produce a grain-oriented silicon steel sheet. At this time, as the atmospheric gas at 800 to 1200 deg.C in the temp. railing stage in the finish annealing, a gaseous mixture of N2 and H3 is used, and in the case the ratio of the gaseous N2 is defined as N (%), the relationships of N<=90 and 0.19XAlR +7.8<=N<=0.45XAlR-1 [AlR: {acid soluble Al-(27/14)XN}ppm] are satisfied, and the oxygen potential in the annealing atmosphere PH2O/PH2 is regulated to <=0.020. |
