Galvanized steel pipe passivation

Passivation treatment is an essential process for galvanized steel pipes that need to be stored or transported over extended periods. This treatment helps to prevent corrosion, commonly known as "white rust," during storage and transit. Two widely used passivation methods are chromate and phosphate treatments. Below is an overview of the key steps involved in passivating galvanized steel pipes.

Spray Passivation Method:
The passivation solution is directly sprayed onto the hot-dip galvanized steel pipe. The spray should be applied from a distance of approximately one meter, ensuring that the solution is evenly distributed over the surface. After spraying, the pipe should be wiped clean using a steam knife to remove any excess liquid. It is essential to ensure that the liquid is blown off thoroughly to prevent any leftover moisture that could lead to corrosion.

Compressed Air Wipe:
After the passivation solution has been sprayed, compressed air is used to blow off any remaining liquid from the surface of the steel pipe. This step helps to ensure that the passivation coating is applied evenly across the surface. By adjusting the air pressure, the thickness of the coating can be controlled. It is critical that no excess liquid remains on the surface of the galvanized pipe, as this could form undesirable liquid beads that may negatively impact the coating's effectiveness.

Passivation helps to enhance the durability of galvanized steel pipes, ensuring that they remain free from corrosion during storage and transportation. Proper application of the passivation solution is essential to achieving a uniform coating that provides long-term protection for the steel pipes.