Composite repair is not limited to pipework: HSOS Industrial Services restored a DN250 dished end with localised corrosion damage and perforations using wet lay-up lamination and a ceramic-filled topcoat – all carried out on site in North Rhine-Westphalia.
Scope of Work
Composite repair techniques are commonly associated with pipelines, but they are equally applicable to pressure vessel components. In this case in North Rhine-Westphalia, a DN250 dished end had suffered localised wall-thickness loss and through-holes due to corrosion. Immediate component replacement was neither logistically nor economically viable.
Method
The HSOS team completed the full repair on site:
- Surface preparation: Abrasive blasting to Sa 2.5 per ISO 8501-1; all voids and perforations were filled flush with a high-build epoxy filler.
- Laminate build-up: Glass-fibre woven fabric was applied layer by layer using a two-component epoxy resin system. Ply count and orientation were engineered in accordance with ASME PCC-2 Article 4.1 and ISO 24817 to meet the component's mechanical demands.
- Ceramic-filled topcoat: A ceramic-loaded finish coat was applied as the final layer, significantly improving erosion and corrosion resistance and protecting the laminate against chemical attack and mechanical wear in service.
Why Lamination Instead of Welding?
On thinned or corrosion-fatigued dished ends, welding carries the risk of further heat distortion and additional wall thinning. Cold lamination introduces no heat input, generates no residual stress profile, and can be executed during reduced-pressure operation without a full shutdown. The applied composite provides a defined, measurable wall-thickness addition.
Outcome
Following cure, the dished end was re-commissioned after visual inspection and ultrasonic thickness verification. The ceramic topcoat delivers a smooth, chemically resistant surface that actively resists under-film corrosion. The entire scope was completed within a single shift – considerably faster than a component replacement would have required.
Conclusion: Composite lamination is not purely a pipe repair method. Wherever curved or formed vessel surfaces require rehabilitation, the process delivers code-compliant, permanently sealed results – rapidly, without heat, and cost-effectively.