| 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:
|
| A. |
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. |
| B. |
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. |
| C. |
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. |
| D. |
Removal
of acidic impurities.
After acid cleaning, the components shall be rinsed thoroughly
in water for removal of all residual impurities. |
| E. |
Phosphating
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’. |
| F. |
Water
Rinsing.
After phosphating, all the components shall be rinsed
thoroughly in water for the removal of residual phosphoric
acid and sodium nitrite. |
| G. |
Passivation
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 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. |
