1.What is the impact on the anti-corrosion life?
The anti-corrosion principle of the galvanized layer is to protect the substrate through the sacrificial anode effect and physical barrier effect of zinc. The thicker the zinc layer (the heavier it is), the stronger the anti-corrosion ability and the longer the service life.
2.What effect does a mildly corrosive environment have on service life?
In such an environment, the zinc layer is consumed slowly (annual corrosion rate is about 1-3g/㎡).
If the difference in zinc layer is 5g/㎡: the original 80g/㎡ zinc layer can last about 25-30 years, and 75g/㎡ is about 23-28 years, the difference is only 2-3 years, and in actual use it may be covered up by other factors (such as surface treatment, maintenance), and the impact is not obvious.
If the difference is 10g/㎡: the life span difference is about 3-5 years, which has little impact on interior decoration and low-frequency parts (such as furniture frames).
3.What effect does a moderately corrosive environment have on service life?
The annual corrosion rate of the zinc layer is about 3-8g/㎡, and the impact of a few grams of difference will be magnified.
5g difference: The life of the zinc layer of 80g/㎡ is about 10-15 years, and 75g/㎡ is about 9-14 years, with a difference of 1-2 years; if used for outdoor guardrails and ordinary steel structures, it may cause local premature rust (such as welding points and edges).
10g difference: The life is shortened by 2-4 years. If the product design life is required to be 15 years, the difference of 10g may lead to increased maintenance costs in the later stage (such as repainting and replacement).
4.What impact does a severely corrosive environment (such as coastal areas, industrial areas, and high humidity environments) have on service life?
The annual corrosion rate of the zinc layer can reach 8-20g/㎡, and the difference of "a few grams" has a significant impact.
5g difference: For example, in coastal areas (high salinity), the life of 80g/㎡ zinc layer is about 4-8 years, and 75g/㎡ is about 3.5-7 years, with a difference of 0.5-1 year, but the substrate may be corroded first (such as bolts and corners) due to the premature exhaustion of the local zinc layer.
10g difference: The life is shortened by 1-3 years. If used in chemical equipment, marine engineering and other scenes with extremely high anti-corrosion requirements, it may cause early failure (such as coating penetration and substrate rust), which directly affects product safety.
5.What effect does a few grams of zinc coating have on processing performance?
Thin zinc layer: If the difference is 5g, the local zinc layer may be too thin. During stamping and bending, the thin zinc layer area is prone to cracking due to excessive deformation of the substrate, resulting in "exposed bottom", increasing the risk of later corrosion.
Thick zinc layer: If the difference is 10g, the overly thick zinc layer may produce more zinc vapor during welding, resulting in pores and spatter, or cracking due to insufficient ductility of the zinc layer during deep drawing.