Production and treatment measures of white rust on galvanized steel grating

After long-term transportation, the galvanized steel grating products have a large amount of white or gray powder on the surface of the original bright and smooth product, and the product is black, and even rust spots appear in serious places. In fact, when the newly plated galvanized steel grating is stored and transported in a densely packed and ventilated environment in a densely packed environment, white or gray powdery corrosion products are formed on the surface of the coating. It is usually called white rust.
If the surface of the galvanized layer of steel grating adheres to a layer of condensed water and reacts with oxygen, carbon dioxide, hydrocarbon, sulfur dioxide, soot, dust and other chemical gases, it becomes a corrosive aqueous solution and adheres to the plating. On the surface of the zinc layer, an electrolyte is formed, which is electrochemically corroded with a zinc layer having poor chemical stability, thereby producing a powdery corrosion product called white rust.
Causes of corrosion of steel walkway grating
1 indoor air humidity is high;
2 The finished product is not dried and stored in the warehouse;
3 A layer of water film is condensed on the surface of the zinc plate of the steel grating. When the moisture content in the air reaches 60% or in the range of 85-95%, and the pH is <6, the corrosion reaction is more severe. When the water temperature is as high as 70 °C, it has the fastest corrosion rate to the galvanized layer.
Method for preventing white rust of steel grating
1 When the steel grating is stacked, there is no condensed water on the surface. Special shipping packages must be good when transporting.
2 Air circulation should be maintained in the warehouse, and the relative humidity of the air should not be in the range of 60% or 85~95%;
3 Steel grids should be stacked without harmful gases and excessive dust
4 The surface of the galvanized steel grating is oiled and passivated.
Treatment measures after white rust
In most cases, white rust does not indicate that the Black Steel Grating has been severely damaged, and does not necessarily mean that the service life of the galvanized steel grating will be reduced. After white rust occurs, the plated parts of the original close-pack should be opened to dry the surface quickly and inspected immediately.

When the white rust on the surface of the galvanized steel grating is slight, use a dry cloth to wipe off the rust. Because in the humid environment, the very slight white rust on the surface of the steel grating may also hinder the formation of the protective film of the basic zinc carbonate corrosion product.
Medium to severely corroded steel gratings can be removed with a stiff brush and cannot be brushed with a wire. After removing white rust, the thickness of the coating on the white rust must be checked to ensure adequate galvanized layer protection.
Typical white and gray corrosion products may turn black on steel slabs that have been stored for a long time. When this happens, it means that a large number of galvanized layers have been corroded and the service life will be reduced. In extreme cases, due to long-term storage in harsh environments, severe white deposits or red rust, which have damaged the service life of the steel grating, must be re-plated or partially repaired in accordance with the relevant standards.
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