The heat resistance of laminated silicon steel sheets is much better than that of galvanized steel sheets and cold-rolled steel sheets. When used, due to the specific combination of steel sheet substrate and coating structure, an iron-aluminum alloy is formed during use. Has excellent high temperature resistance. At about 450 ° C, extremely high reflectivity is guaranteed. When it is used for a long time under about 550 degrees, it hardly changes, and still maintains its beautiful luster. However, when it is higher than about 600 degrees, it is alloyed due to interdiffusion of iron and aluminum, and the surface layer gradually changes from gray to dark color. However, the melting point of the metal layer is very high, that is, or exceeds the melting point of aluminum, and it does not melt and precipitate. The heat resistance of the aluminized steel sheet (500-600 ° C) is almost the same as that of the stainless steel sheet, and is 20 times better than the cold rolled steel sheet.
Thermal reflection properties of laminated silicon steel sheets
The surface of the aluminized steel sheet is not only beautifully processed, but also has excellent reflection performance, and has a light reflectance of about 80% at a temperature of 500 ° C or less; and a reflectance of 95% under infrared rays. Therefore, the aluminum plate can be made into an efficient heat barrier or a heat reflector in high temperature applications, and the temperature inside the furnace is rapidly increased by effective heat reflection.
Aluminum in laminated silicon steel sheets tends to be more resistive than Mn, Mo, Cr, W, Cd, Fe, and Zn in the ion series. However, since the aluminum oxide film itself has good stability, the corrosion resistance of the surface layer is much better than that of the galvanized steel sheet except for some environmental conditions. During the hot dip coating process, the molten aluminum immediately reacts with oxygen in the air to form a protective layer of Al2O3, which immediately passivates the surface of the steel sheet. This protective layer itself is very stable and insoluble in water, and even if the surface of the steel sheet is scratched, this protective layer has a self-healing function. Therefore, the aluminum plate has a strong corrosion resistance to chemical corrosion.