The selection of the zinc coating thickness for galvanized coil needs to be comprehensively judged based on the corrosion level of the operating environment, the thickness of the substrate, and the design life requirements. National standards should be prioritized, while also matching the actual operating conditions.
Selecting Zinc Coating Thickness Based on the Operating Environment Different environments significantly affect the corrosion rate of the galvanized coating. Selection should be based on these classifications:
- Dry Indoor Environments (e.g., warehouses, general factories): Low corrosivity; galvanized coils with a zinc coating weight of 120–180 g/m² (approximately 17–25 μm) can be selected.
- General Atmospheric Environments (urban, rural): It is recommended that the zinc coating weight be no less than 275 g/m² (approximately 38 μm), corresponding to an average hot-dip galvanized coating thickness ≥55 μm.
Harsh corrosive environments (coastal areas, chemical industrial zones, high humidity and high salinity areas): High corrosion resistance configurations are required, with a zinc layer weight of 275 g/m² or more, and locally even 350 g/m² (approximately 49 μm), in addition to passivation treatment to extend service life.
