Reasons Why the Product Quality of Dry Hot-Dip Galvanized Zinc is Better Than Wet Hot-Dip Galvanized Zinc

During the "dry" hot-dip galvanizing process, aluminum can be added to the molten zinc to improve the structure and thickness of the iron-zinc alloy layer, resulting in a bright pure zinc layer and good bending properties. At the same time, during hot-dip galvanizing, the solvent has already been coated onto the surface of the steel tube, and the zinc chloride in the solvent has already started to react slightly with the steel substrate. As the steel tube is heated during drying, the reaction accelerates. Therefore, once the steel tube is immersed in the molten zinc, the reaction between iron and zinc reaches its peak, allowing sufficient reaction time between iron and zinc from the application of the solvent to the immersion in zinc. This makes it difficult for missing galvanization to occur. However, the "wet" hot-dip galvanizing process lacks these favorable conditions. Firstly, aluminum cannot be added to the molten zinc surface. Even if aluminum is added, it will react with the chloride solvent to form aluminum chloride and volatilize. At the same time, in "wet" hot-dip galvanizing, the steel tube only starts to contact a thin layer of flux on the molten zinc surface when it is devoid of zinc. Therefore, the time for applying the flux is very short, and the chemical cleaning power is relatively weak. The activation of the steel tube surface is insufficient, which affects the iron-zinc reaction, making it prone to missing galvanization.