| 摘要 |
<p>PROBLEM TO BE SOLVED: To promote the purification of a steel sheet at the time of finish annealing and to shorten the annealing time or to reduce the annealing temp. by subjecting a cold rolled sheet contg. specified amounts of Al and N to primary recrystallization annealing and nitriding treatment to form into a coil and executing finish annealing while atmospheric gas is allowed to flow into the space between sheets. SOLUTION: A cold rolled sheet contg., by weight, 0.01 to 0.06% acid soluble Al and 0.005 to 0.013% N is subjected to primary recrystallization annealing, is coated with a separation agent for annealing as it is or after nitriding treatment and is coiled into a coiled shape. This coil 1 is charged into an inner cover 9 of an annealing furnace 10. Then, while atmospheric gas contg. gaseous hydrogen is fed to the space between coil sheets from the vent holes 3 of a base plate 2 through a humidifier 6 and a preheater 5, the coil 1 is heated to >=1050 deg.C to execute finish annealing to obtain a grain oriented silicon steel sheet. In this way, an inhibitor such as AlN is purified in a short time by finish annealing to attain the reduction of the defect of the shape, the reduction of the treating time, the improvement of thermal efficiency or the like.</p> |
