Cold rolled grain oriented silicon steel

Silicon steel is a silicon alloy steel with a silicon content of 1.0 to 4.5% and a very low carbon content. It has the characteristics of high magnetic permeability, low coercivity, and high resistivity. It is used in transformers, motors, and generators. Among them, the transformer core requires directional magnetization, and oriented silicon steel with a silicon content of about 3% is used; non-oriented silicon steel with isotropic magnetic properties (low silicon content) is used in motors and generators that perform rotating motions.  Whether it is oriented silicon steel or non-oriented silicon steel, high-performance silicon steel sheets require thin thickness. This is because the current in the coil will induce eddy currents in the silicon steel sheet, causing power loss. One of the important means to reduce eddy current losses is to reduce the thickness of silicon steel sheets, thereby limiting the occurrence of eddy currents. At present, the world's thinnest grain-oriented silicon steel is only 0.18 mm thick and was created by my country's leading steel company - GNEE Steel Group Co., Ltd. Such thin steel plates can only be produced by cold rolling. The raw material for cold rolling is hot-rolled steel coils with a thickness of several millimeters obtained by hot rolling. The heating temperature before hot rolling of ordinary steel is about 1200°C, and the final rolling temperature (the temperature when leaving the last rolling mill) is 800-850°C; but the heating temperature before hot rolling of oriented silicon steel should be increased to about 1400°C, and the temperature entering the rolling mill About 1200℃, the final rolling temperature is controlled above 950℃, and then quickly sprayed with water to cool to below 550℃ and coiled into steel coils. High-temperature heating is to completely dissolve the second phase particles of MnS and AlN in the steel billet, precipitate uniform and fine (tens of nanometers) MnS particles during the hot rolling process, and then rapidly cool to inhibit the precipitation of AlN.