Details of Pre-treatment and Painting Methods.
After necessary machine operations like, shearing, punching and bending there is residue of Oil on products. It is important to remove this to ensure good quality paint finish and long life of the product.
To achieve this, all fabricated components shall be subjected to elaborate surface treatment process by four step seven tank special anti corrosion treatment consisting of the following steps:
- Degreasing (Alkaline Cleaning)
This process shall remove oils and other semi solids from metal surface of the rack components. Caustic soda, soda ash, Tri-sodium phosphate and sodium metasilicate in the right concentration under closely controlled temperature limits shall be ensured for this process. This process shall be done in conformity with IS 6005 of 1970.
- Removal of alkaline impurities
After degreasing, the components shall be rinsed in water for the removal of any alkaline impurities from the surface of the rack components.
- Pickling (Acid cleaning)
All the rack components after degreasing and rinsing shall be subjected to acid cleaning for removal of all rust and scales by using Sulphuric Acid Solution. The process shall be done in conformity with IS 6005 of 1970.
- Removal of acidic impurities
After acid cleaning, the components shall be rinsed thoroughly in water for removal of all residual impurities.
The cleaned metallic surface of the rack components shall be subjected to phosphating process to prevent the surface from any type of further corrosion by treating the components in Phosphoric acid tank. Sodium nitrite shall be used as accelerator to impart a fine texture to phosphate coating. The process shall be done in conformity with IS 6005 & 3618 of 191996, class 'D'.
- Water Rinsing
After phosphating, all the components shall be rinsed thoroughly in water for the removal of residual phosphoric acid and sodium nitrite.
All the components after rinsing the same in shall passivate rinsing dilute chromic acid. The passivation will leave a light chromate coating, which will increase corrosion resistance, humidity resistance and paint adhesion to the metal surface
After chemical treatment the items are Spray or dipping Painted with high quality Paint purchased from reputed suppliers. After painting, the items are oven baked in our special oven @120 degrees for 30 minutes, to ensure long life and good finish.