Painting → baking paint → surface decorative effect paint → spraying transparent paint → antirust treatment and antirust technology of wrapped wrought iron guardrail At present, the most effective and practical antirust method of wrought iron guardrail is hot dip galvanizing. That is, a zinc-iron alloy layer and a pure zinc layer are formed on the surface of the wrought iron guardrail in molten zinc to isolate the opportunity of oxidation of wrought iron workpieces. The rust-proof period is as long as 20-50 years, which is safe and reliable without maintenance. It is the best antirust method for wrought iron workpieces.
Hot dip galvanizing process
1. Before pickling, check whether the wrought iron workpiece has galvanized process holes in our factory (exhaust, in and out of zinc night, hanging), the corrosion degree of the surface of wrought iron workpiece, and whether the surface covering can be removed by hydrochloric acid (whether there is paint, grease, etc.). , should use fire, grinding, alkali washing and other methods to remove).
2. Degreasing (alkali washing) is equipped with heating equipment to eliminate grease and paint on the surface of wrought iron workpiece.
3. Wash with water to remove alkaline water and attachments on the surface of wrought iron workpiece.
4, pickling to remove rust, scale and other surface coverings.
5. Check the treatment after pickling: whether the pickling effect is satisfactory. If the pickling is insufficient, it should be cleaned again. If the pretreatment before pickling is not thorough, it should be reprocessed before cleaning.
6. Rinse with water to remove acid water and other attachments on the surface of wrought iron workpiece.
7. Wash the surface of the workpiece again with plating AIDS to ensure that the surface does not rust before galvanizing.
8, drying to improve the temperature of wrought iron workpiece, avoid too much water on the surface of wrought iron, explosion when galvanized.
9. The hot-dip galvanized workpiece is immersed in molten zinc at the temperature of 440℃-470℃. After a period of time, it is suggested to coat zinc-iron alloy layer and pure zinc layer on the surface of wrought iron workpiece.
10. Passivation provides atmospheric corrosion resistance of workpiece surface, and reduces or prolongs the time of white rust.
1 1. Cooling prevents the workpiece from shrinking due to cooling, which leads to the rupture of the assembly structure. 12, finishing to remove zinc particles and zinc ash attached to the coating surface.
13, inspection and determination of inspection coating, and appearance inspection of workpiece.