At present, hot dip galvanizing is an effective and practical anti rust method for cast iron guardrails. That is to say, a zinc iron alloy layer and a pure zinc layer are formed on the surface of the cast iron guardrail in the molten zinc liquid, so as to isolate the chance of iron work pieces being oxidized. The antirust period is more than 20-50 years without maintenance. It is safe and reliable. It is a good antirust method for iron work pieces.
Technological process of hot dip galvanizing
1. Inspection and treatment before pickling
Check whether the ironwork pieces have the process holes for galvanizing in our factory (exhaust, zinc night, hanging), the corrosion degree of the surface of the ironwork pieces, and whether the surface covering can be removed by hydrochloric acid (if there is paint, grease, etc。, it should be removed by fire, grinding, alkali washing, etc。)。
2. Degreasing (alkali washing)
Equipped with heating equipment to eliminate grease and coating on the surface of iron work pieces。
3. Water washing
Remove alkaline water and attachments on the surface of iron work pieces.
Remove rust, scale and other surface coverings
3d捕鱼5。 Inspection and treatment after pickling:
Whether the pickling effect is ideal, if the pickling is not sufficient, pickling again, if the pickling is not thorough, it needs to be treated again and then pickling again。
6。 Water washing
Remove acid water and other attachments on the surface of iron work pieces
7. Upper plating aid
Clean the surface of the workpiece again to ensure that the surface does not rust before galvanizing。
Increase the temperature of iron work piece to avoid too much water on iron surface and explosion during galvanizing。
9。 Hot dip galvanizing
3d捕鱼When the workpiece is immersed in molten zinc at 440 ℃ - 470 ℃ for a certain time, a layer of zinc iron alloy and pure zinc coating are obtained on the surface of the workpiece。
Provide the corrosion resistance of workpiece surface to atmosphere, reduce or extend the time of white rust.
It can prevent the work piece from chilling and shrinking, resulting in collective structure cracking.
Removal of zinc nodules and zinc dust adhering to the coating surface
Inspection and measurement of coating, appearance inspection of workpiece.