| 摘要 |
PURPOSE:To manufacture the grain-oriented silicon steel sheet excellent in the magnetic property in an industrially stable manner by respectively prescribing the atmospheric gases for the secondary re-crystallization annealing and the purifying annealing in the finish annealing of the grain-oriented silicon steel sheet containing Si of a specific amount. CONSTITUTION:The grain-oriented silicon steel sheet containing 0.8-6.8wt.% Si is primary re-crystallization annealed in common with the decarburization in the wet gas after the cold rolling. The steel sheet is nitrided to increase the nitrogen content to reinforce the nitride as the inhibitor. One or more kinds of Al, Ti, V, Nb, Zr, Ta and Cr is preferably used as the element to form the nitride contained in the grain- oriented silicon steel sheet. Then, the separation agent for annealing is coated on this steel sheet to perform the finish annealing. The partial pressure of nitrogen in the atmospheric gas for the finish annealing is >=1 atm during the secondary re- crystallization annealing, the nitride is further reinforced to stabilize the high magnetic flux density, and 100% hydrogen gas is realized in the purifying annealing to purify the nitride. The grain-oriented silicon steel sheet with high magnetic flux density is obtained through the specific treatment. |
