Meishen Technology Company
After decarburization and annealing of oriented silicon steel in a continuous furnace, it is necessary to uniformly coat the upper and lower surfaces of the strip steel with magnesium oxide coating liquid. Magnesium oxide mainly acts as a release agent to prevent the strip steel from sticking during the high temperature annealing stage. At the same time, it can remove impurities such as nitrogen and sulfur in the steel. In addition, it also reacts with the silicon dioxide on the surface of the silicon steel to form an excellent magnesium silicate insulating underlayer . Therefore, the coating quality of magnesium oxide coating liquid on the surface of oriented silicon steel plays a vital role in the quality of silicon steel products.
At present, the magnesium oxide coating solution is applied by a two-roll coater. The two-roll coating machine includes an upper coating roller, a lower coating roller, a tray, a magnesium oxide coating liquid circulating device, and a nozzle that sprays the magnesium oxide coating liquid in the magnesium oxide coating liquid circulating device to the upper surface of the strip steel The undercoating roller is immersed in the tray, and the magnesium oxide coating liquid sprayed by the nozzle on the upper surface of the strip overflows and enters the tray. The undercoating roller uses the magnesium oxide coating liquid in the tray for the lower surface of the strip Of coating.
However, due to the magnesium oxide coating liquid in the process of coating and recycling, the magnesium oxide solution in the tray does not flow smoothly, the magnesium oxide reacts with water to form magnesium hydroxide precipitates, and the magnesium hydroxide combines with carbon dioxide in the air to form easily precipitated Magnesium carbonate. Magnesium carbonate and magnesium hydroxide have poor fluidity and are prone to agglomeration and deposition. Therefore, the fluidity of the coating liquid in the tray is not high. As time goes by, the coating liquid is easy to accumulate and scale, resulting in poor coating quality of the lower coating roller, and the batches of wide and narrow and different quantities appear along the strip rolling to the plate surface. Double lines and abrasion of the lower coating roller directly cause product quality defects. In severe cases, it is necessary to stop the machine to replace the coated roller, clean up the blockage of the circulation pipeline, and handle the scale of the tray. On the one hand, these unfavorable factors greatly increase the labor intensity of employees, and on the other hand, they interfere with on-site continuous production and directlyaffects production efficiency, and at the same time, the cured magnesium oxide coating liquid is stuck in the tray and cannot be used, which not only is difficult to clean, but also causes a waste of magnesium oxide. In addition, due to the liquid thrown at the edge of the coating roller, the coating quality is affected, and the work of the coating machine is disturbed at the same time.