Hot - Dip Galvanizing of Steel Structures
Hot – dip galvanizing is a process of immersion of a steel structure in a bath with a 450-degree Celsium zinc melt.
After the structure is removed, an oxide-carbonate film is formed on the zinc-coated surface, – this is a protective layer, which protects from further oxidation.
In order to improve the technological process, we use zinc together with nickel in the process, which improves the plastic and anti-corrosion characteristics of the metal alloy, making the coating smoother and shiny.
The use of modern lifting mechanisms and transporting lines, as well as the design of the bath, ensure uniform coverage of metal structures.
The thickness of the zinc coating on the galvanized metal structure is according to ISO 1461 requirements. The annual consumption of zinc coating is, on average, 2 μm. Thus, the service life of the protective zinc coating, with a thickness of, for example, 80-100 μm is 20 to 50 years, depending on the type of environment.
The technology of hot dip galvanizing includes the following necessary processes:
1. Degreasing
The steel structure is immersed in a hot solution (45-50 ° C) of phosphoric acid.
2. Pickling
The steel structure is immersed in an aqueous solution of hydrochloric acid (6-15%) and an inhibitor. The temperature is 30 ° C.
3. Washing
The steel structure is immersed in industrial water. The temperature is 30 ° C.
4. Fluxing
The steel structure is immersed in an aqueous solution of zinc chloride (150-300 g / l) and ammonium chloride (100-150 g / l). The temperature is 60 ° C.
5. Drying process
The steel structure is placed in a preheating chamber (70-90 ° C) with recirculation of hot air, which ensures complete drying.
6. Galvanizing
The metal structure is lowered at high speed into a bath with molten zinc, then slowly removed.
Locations of HDG lines of EUROFORMAT Stalkonstrukcia :
– Sarny, Rivne region of Ukraine;
– Zaporozhye, Ukraine.
Working dimensions of HDG lines
– Sarny: 10.5х3х1.6 m. The maximum length of steel structures could be up to 12 m.
– Zaporozhye: 7х3х1.5 m. The maximum length of steel structures could be up to 6.9 m.
Quality management system
The production unit in Sarny supports ISO 9001:2015 quality assurance system.
The quality of HDG coating corresponds with requirements of ISO 1461.
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