GI coil and GL coil white rust causes and prevention and treatment methods

Apr 28, 2024

Li Cheung Steel believes that everyone is no stranger to GI and GL coils. But how much do you know about the problem of white rust occurring on galvanized/aluzinc plated products? When galvanized and aluminized zinc plated products are stored and transported in a humid environment, the surface of the plating is susceptible to electrochemical corrosion due to the lack of free-flowing air on the surface, resulting in the appearance of white or gray powdery corrosion products, i.e., white rust. Although white rust generally does not have much effect on the corrosion resistance of the plating, it may become serious if it is kept in a humid and confined environment for a long period of time, thus affecting the appearance and service life of the product.

Here we summarize the reasons for white rust, as well as some preventive and treatment measures.

1, the reasons for white rust:
By observing the products where white rust occurs, it is found that the parts where the white rust is mild still have a hot-dip galvanizing layer of sufficient thickness to protect the steel base, whereas the plating layer is almost completely consumed in places where severe white rust occurs, and no protection can be provided. White rust occurs as a result of a chemical reaction between moisture on the surface of the coating in a closed environment and oxygen, carbon dioxide, and other oxides, which produces a corrosive aqueous solution that adheres to the surface of the coating, forming an electrolytic solution that produces a white powdery white rust. The severity of white rust depends on the composition of the condensate and the duration of the environment.

2, the prevention of white rust:

1) In the packaging can be put a few desiccant

2) Fine packaging of steel coil, waterproof paper + plastic film + steel coil outer packaging

3)Keeping low humidity environment around the steel coil and enough ventilation can reduce the white rust.

iGI GL Packaging — iGI GL Coils Packaging

3,Processing of white rust
1) Slight white rust can be dried in a ventilated place for a period of time and can be wiped off with a dry cloth.
2) Medium white rust can be removed with a hard brush (note that you can not use a wire brush).
3) Heavy white rust with sandpaper lightly sanding, and then brush galvanized special repair paint for repair (galvanized special repair paint is more than 95% zinc content of high zinc paint).

Author: Bella Niu

The Introduction Of Author

I am a very very enthusiastic person and I am very very glad to help you if I have any chance. If you have GI, PPGI, GL, PPGL , Roofingsheet steel industry confusion, or If you have steel internet marketing questions, or 2024 a direction, or you have ideas to make investments in 2024, or you are making adjustments, you're not quite clear, welcome to come to Li Cheung Steel Bella for advice as soon as possible.
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