Abstract: Effect of inner cover pressure and heating rate of car-type furnace on high temperature annealing quality of grain-oriented silicon steel was studied. The results showed that the inner cover pressure affected the quality of forsterite film by controlling water vapor discharge. Moderate pressure was conducive to the formation of uniform and continuous forsterite film, while too large or too small pressure caused forsterite film to be thin, and even appeared bare crystal phenomenon. The change of the position of the inner cover caused the difference in the heating rate of oriented silicon steel, which affected the magnetic property. The heating rate of the inner cover in the middle area of the car-type furnace was conducive to optimize the magnetic property, while the heating rate of the inner cover near the furnace door or the furnace wall leaded to the decrease of the magnetic property.

Key words: grain-oriented silicon steel, pressure, temperature, forsterite film, magnetic properties