Throughout the lifecycle of a steel structure, corrosion acts as an ‘invisible enemy’ that threatens structural safety and drives up maintenance costs. Statistics show that 70% of maintenance costs for steel structures typically stem from anti-corrosion repairs carried out in the middle and later stages of a building’s life.
By employing scientific paint application techniques, it is possible not only to extend the service life of a building to 25 years or even 50 years or more, but also to significantly reduce the hidden costs associated with repeated repainting during long-term operation.
Below is a summary of the core practices for high-standard corrosion protection in steel structures:
1. Surface Preparation: The ‘lifeline’ of corrosion protection
60% of the quality of corrosion protection depends on surface preparation. We strictly adhere to the Sa 2.5 (near-blanco, ISO 8501‑1 ) sandblasting standard:
Removal of contaminants: Cleaning the surface of oil, grease and other contaminants.
Sandblasting: Removes scale, rust and foreign matter, ensuring the metal surface has an appropriate roughness (approximately 70 micrometres).
Enhancing Adhesion: Increases the contact area between the paint and the steel, preventing the paint film from flaking off in patches at a later stage.
2. Multi-layer coating systems: layered protection, each layer fulfilling its specific role
In accordance with the ISO 12944-6 standard, we have selected the optimal coating combinations for different environments (C3 urban, C4 industrial and C5 marine environments):
Epoxy zinc-rich primer (electrochemical protection, zinc content ≥60%): Utilising the sacrificial anode effect of zinc powder, this prevents the spread of corrosion even if the coating suffers minor scratches.
Epoxy micaceous iron oxide intermediate coat (barrier function): Flake-shaped micaceous iron oxide effectively blocks the penetration of moisture and oxygen, enhancing coating thickness and protection.
Acrylic polyurethane/fluorocarbon topcoat (weather-resistant and aesthetically pleasing): Provides excellent UV resistance, colour retention and reflectivity, ensuring the building retains its fresh appearance over time.
3. Precise Process Control: No Shortcuts
Professional coating involves more than just spraying; it also entails rigorous monitoring of physical parameters:
Dry Film Thickness (DFT) Monitoring: Ensuring that every coat of paint meets the design-specified thickness to the micrometre.
Temperature and Humidity Monitoring: Strictly controlling the application environment to prevent moisture being trapped within the paint film during high-humidity conditions, which can lead to blistering or premature failure.
Adhesion testing: Following the completion of paint application for each batch of products, a proportionate sample is selected for pull-off testing to assess paint adhesion, ensuring compliance with technical standards(ASTM D‑4541＞5 MPa).
4. The long-term benefits of reducing operating costs
Although high-quality coatings involve a slightly higher initial investment, the economic benefits are clear:
Reduced downtime for repairs: There is no need for major shutdowns for repairs every 3–5 years.
Increased asset value: A sound structural condition translates into higher property values and lower insurance premiums.
We invite you to choose our company for a comprehensive, one-stop solution. By combining advanced manufacturing techniques with a rigorous anti-corrosion system, we deliver premium steel structures that are truly built to last.
If you’re unsure how to proceed, please contact us for a free integrated steel structure solution, preliminary layout plans and a quotation.