Corrosion protection – Power coating

Treatment before Powder coating 

Power coating method is employed for cleaning off the grease, rust and impurities on the LF space frame pipe elements and bolts, and for the protection of their surface by applying a protective coat prior to the powder coating in order to secure a perfect adherence of the paint.

Powder coating of the black pipes 

• The pipes are put in a 60-70℃ hot alkali bath for 5-10 minutes for degreasing.
• After the alkali bath, the pipe are put in a bath of PH=6-9 for at least 2 minutes for rinsing.
• The pipes are kept in the 60℃ hot acid bath thanks until everything on the pipes is cleaned of,and the natural metallic color can be seen.
• After the acid bath, the pipes are put in a bath of PH= 6-9 for at least 2 minutes for rinsing
• The pipes thus cleaned and rinsed, are put in an iron phosphate bath of PH=4-5.5 for 5-10 minutes until the surface of the metal gets the color of iron phosphate.
• After the phosphate bath, the pipes are put in a bath of PH=6-9 for at least 2 minutes for rinsing.
• Then the pipes are undergoing a passivation process by waiting for 0.5-5 minutes in a bath of PH=4-5.5. 
• Then the pipes are dried in an oven of 120℃ for 30-45 minutes.
• The hot air is removing any dust particles which might stick to the pipe surface later on.