PTFE Internal Coating of Hydraulic Accumulator Shells
AST coats hydraulic accumulator shells internally with a Chemours PTFE system for the Australian operation of STAUFF — a global manufacturer of hydraulic and fluid-power components.
Accumulator shells are a good example of the closed-geometry work AST handles routinely: the coating that matters is the one you cannot see, the part has to be treated as a sealed component through the oven cycle, and the customer needs the same result on every batch rather than a good result once.
Protecting a bore you cannot easily reach
Hydraulic accumulator shells are pressure components with a closed internal geometry. The bore has to be protected against internal corrosion and finished to a clean, chemically inert internal surface — but the geometry makes both the application and the cure harder than they would be on an open part. Coating material has to reach the full internal surface, and any air trapped inside a sealed component has to have a relief path during the oven cure. The customer needed the work done to a documented, repeatable specification, batch after batch.
- Closed-geometry pressure component
- Internal corrosion protection required
- Clean, inert internal surface finish
- Repeatable, documented specification
Inspect, strip, blast, coat, cure — every batch the same
Every shell is inspected on receipt and the internal surface assessed before any processing begins. Parts are degreased, then run through a thermal burn-off to remove existing coating and organic residue, followed by silica bead blasting to establish the anchor profile the PTFE system needs for adhesion. Because these are closed-geometry parts, pressure equalisation is confirmed as a standing pre-coat check — on these shells the existing port opening provides the relief path during cure, so no additional vent is required. The internal PTFE system is then applied and cured.
- Inspection and condition assessment on receipt
- Degrease, thermal burn-off, silica bead blast
- Port opening confirmed as the cure relief path
- Internal spray application and controlled cure
Chemours PTFE, applied internally
PTFE suits this duty. It is a thin-film fluoropolymer system that is chemically inert and low-friction, applied to the internal surface of the shell and cured to specification. Dry film thickness is verified and recorded as part of the QA release on every batch, and a materials Certificate of Conformance is available with the job.
- Chemours PTFE internal coating system
- Thin-film, chemically inert, low-friction
- Dry film thickness verified and recorded
- Materials Certificate of Conformance available
Returned to service, then a standing program
The shells returned to service and the work has since become a repeat program, with each batch processed to the same documented route. Turnaround is 7–10 working days from receipt of parts, and every job carries AST's lifetime workmanship warranty.
- Parts returned to service
- Now a repeat coating program
- 7–10 working days from receipt
- Lifetime workmanship warranty
Sealed and closed-geometry parts are checked for pressure equalisation before they go anywhere near an oven. It is a standing pre-coat step at AST, not a job-specific extra.
Only licensed industrial fluoropolymer applicator in Australia, New Zealand and South East Asia
Yearly technical and quality audits by Chemours Global
Lifetime warranty on workmanship
Coating a closed or internal geometry?
Talk to AST about your component, its service conditions and the internal surface you need. Our team can review the geometry and prepare a technical quotation.