What Is The Production Process Of Non Oriented Silicon Steel

Molten iron is pre-desulfurized, and secondary desulfurization by adding Ca0+CaF: flux or rare earth elements and calcium during converter blowing. The boiling molten steel is decarburized by vacuum treatment and then further desulfurized. Ferrosilicon with low titanium and zirconium content is used for alloying. During continuous casting, it is sealed with argon gas and stirred by electromagnetism. The billet is hot sent to the hot rolling mill and placed in a slow cooling pit. The casting billet above 350C is loaded into a heating furnace and heated to 1200±20C, the final rolling temperature is 850±20C, and the coiling temperature is 600±20C. The thickness of hot-rolled plate is 2.0~2.5mm. Steel with silicon content higher than 2% generally adopts a cold rolling method, which is normalized by 900~1050C (1~3min) before cold rolling, and then cold rolled by a 20-high rolling mill. The secondary cold rolling method can also be used, and after the first cold rolling, it is annealed in the middle of 830~870C (1~3min) in a continuous furnace with a 5%~20%H2+N2 atmosphere, and then cold-rolled to the thickness of the finished product by 8%~10% critical deformation. The final annealing is generally rapidly heated to 850~860C (2~4min) annealing in a continuous furnace with a 20% H2+N2 atmosphere. If decarburization is required, it is best to use two-stage annealing, the front section is decarburized by 800~850C in a wet atmosphere, and the latter section is annealed at a higher temperature for a short time in a dry atmosphere to promote the growth of grains. The tension in the furnace during annealing is best controlled below 2.9N/mm, which can reduce the magnetic anisotropy of the steel plate, and the ratio of longitudinal and transverse iron loss (P15) of the product is 1.1~1.3. After annealing, the steel plate is coated with a semi-organic insulating coating. Large motors that require high interlayer resistance can also be coated with inorganic salt insulating coatings.