Reasonable Correction of Packing Steel Strip to the Temperature of Strip Steel Entering the Zinc Boiler

Reasonable Correction of Packing Steel Strip to the Temperature of Strip Steel Entering the Zinc Boiler
　　According to the classic theory of hot-dip galvanizing, the higher the galvanizing temperature, the faster the inter-diffusion between iron and zinc and the formation of a thicker brittle alloy layer, resulting in the deterioration of the toughness of the coating. Therefore, the old Sendzimir hot-dip galvanizing process imposed strict restrictions on the temperature of strip steel entering the zinc pot, and generally stipulated that the temperature of strip steel entering the zinc pot should not be higher than the temperature of the zinc liquid by 25°C. If the heat brought by the strip steel into the zinc pot cannot maintain the heat balance of the zinc pot, it is better to activate the supplementary heating system of the zinc pot to make up for this lack of heat supply.
　　The new theory of hot-dip galvanizing believes that heat supply at the reaction interface during hot-dip galvanizing can accelerate the formation of Fe2Al5 intermediate layer as a coal-adhesive medium, and good coating adhesion can be obtained. According to this theory, in the production of hot-dip galvanizing, the temperature of strip steel entering the zinc pot is corrected. Practice has proved that when the temperature of the zinc liquid is 450-470℃, the temperature of the strip steel entering the zinc pot is maintained in the range of 480-520℃, which is most beneficial to the formation of a coating with good adhesion. In this case, if the temperature of the zinc liquid is too high due to the high temperature of the strip steel entering the zinc pot, air cooling is used to reduce the temperature of the zinc pot.