The preparation of a directional silicon steel (一 方向性 珪 素 鋼板)

摘要

PURPOSE:To obtain a unidirectional silicon steel plate of high magnetic flux density suitable for the large-sized electrical apparatus and the like by allowing secondary recrystallization to progress while applying temp. gradients in the boundary area of a primary recrystallization area and a secondary recrystallization area. CONSTITUTION:Silicon steel is made into an ingot, which is then subjected to primary recrystallization annealing, thence temp. gradients are given to the steel plate in the boundary area of a primary recrystallization area and a secondary recrystallization area by using a furnace having plural temp. zones, whereby secondary recrystallization and purification annealing are accomplished. The temp. to be applied to this steel strip is kept at =0.5 deg.C per cm, and the temp. of each zone is controlled independently. By this method, the high magnetic flux density unidirectional silicon steel plate having a low rate of increase in watt loss and easy magnetization axis 100 in the rolling direction is obtained.