OVERVIEW: Chemcote were approached to pitfill and recoat this intercooler water box unit from 1981. It was discovered that previous coating applications did not have a uniform thickness. This caused the divider plates to protrude higher than the flange face which resulted in damage to the coating and corrosion on the sealing face.
INDUSTRY
ENVIRONMENT
Up to 60°C Recirculated Water
SUBSTRATE
Cast Iron
CHALLENGE
The intercooler water box unit was manufactured in 1981 and installed shortly after. It was discovered that previous coating applications did not have a uniform thickness, particularly the coating over the divider plate. This caused the divider plates to protrude higher than the flange face which resulted in damage to the coating and corrosion on the sealing face.
SOLUTION
We recommended coating with RB 332, a glass-flake filled vinyl ester coating designed to provide long term protection in this environment. Corrosion on the flange mating faces was resolved by pit filling, assisting the application of a continuous coating film of the specified product.
SCOPE
Internals
High pressure hot wash prior to entry to blast room
Rebates ground on all flange faces to prevent future crevice corrosion
Abrasive blast all internal surfaces
High pressure hot wash to reduce metallic salts below 25ppm
Abrasive blast to AS1627.4 to a nominal profile of 75 μm
Application of one coat of RB 332 on exposed metal surfaces
Rebuild all damaged baffles to original dimensions
Apply second and third coat of RB 332 to achieve minimum thickness of 1,000 μm
Carry out QA to ensure all internal surfaces are defect free
Application of RL 500PF in two coats @ 300 μm and two coats of Luxathane R
PRODUCTS
OUTCOME
Chemcote was able to refurbish the water box covers within the strict time-frame provided by the client. This application will provide at least 20 years of service life.
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