Effect of zinc temperature on hot dip galvanizing performance
Below 480°C, the zinc solution dissolves slowly on the matrix iron. When the temperature of the zinc solution is 430-480°C, the iron loss changes with time according to the parabolic law. Within this temperature range, the resulting alloy is dense and continuous. Therefore, the general hot-dip galvanizing temperature is controlled at about 450 °C. The temperature of 495 °C is the malignant dissolution temperature of zinc to iron. At this time, the coating is loose and is the forbidden zone of hot-dip galvanizing. When the temperature of zinc solution is 490-530 °C, the iron loss has a linear relationship with time. When the temperature of the zinc solution is above 530 °C (up to 580 °C), the reaction returns to the parabolic law. At about 540 °C, the zinc solution has a strong dissolving power for iron and can be used for gray iron castings. However, the higher the temperature, the greater the bonding ability of zinc and iron, the faster the alloy reacts, and the fluidity of zinc liquid increases, so the coating at this time The layer is composed of a thick alloy layer and a thin layer of pure zinc. Since the thick alloy layer is rough in appearance, the coating is rough in appearance. At around 620 °C, the iron-zinc bond layer will form quickly; above 660 °C, the iron will dissolve rapidly and the surface of the workpiece will not hang zinc. This is the temperature that should be avoided.