Corrosion is one of the most critical challenges in steel structure construction, particularly for projects delivered to coastal regions, high-humidity climates, or industrial environments. At our factory, every steel structure component destined for export goes through a rigorous, multi-stage anti-corrosion process designed to meet international project requirements and withstand the demands of long-distance sea freight.
Here is an overview of how we address corrosion protection throughout our manufacturing process — from surface preparation to final packaging.
The first and most critical step is thorough surface cleaning. All steel components undergo shot blasting or sandblasting to achieve a minimum Sa 2.5 cleanliness grade as defined by ISO 8501-1.
This process removes:
- Mill scale and rust
- Welding spatter and slag
- Oil contamination and surface impurities
Beyond cleaning, blasting creates a uniform surface profile (anchor pattern) that significantly improves paint adhesion. Without this step, even premium coatings will fail prematurely.
Once the surface is prepared, primer must be applied within 4 hours to prevent flash rusting and secondary oxidation. Delayed priming is one of the most common causes of coating failure in the field — a step our production process strictly controls.
We use a three-coat protective system for all standard export structures:
| Layer | Function |
|---|---|
| Primer | Corrosion inhibition, adhesion to steel substrate |
| Mid-coat (intermediate) | Film build, barrier protection, pore sealing |
| Topcoat | UV resistance, weathering resistance, aesthetic finish |
The specific paint type used at each layer is selected based on the project's end-use environment (see coating specifications below).
After assembly and fabrication, all of the following areas are inspected and touched up manually before final inspection:
- Weld seams and cut edges
- Bolt holes and connection plates
- Any areas damaged during handling or transport preparation
No bare steel is permitted to leave the factory.
To protect the coating during sea freight, we apply:
- Timber dunnage between stacked members to prevent contact abrasion
- Corner protectors on sharp edges
- Stretch film wrapping on finished assemblies
This is particularly important for shipments to coastal or island destinations where salt spray exposure begins immediately on arrival at the port.
We offer four coating systems to match different project environments and budgets:
Epoxy Zinc-Rich Primer + Epoxy Micaceous Iron Oxide (MIO) Mid-coat + Acrylic / Polyurethane Topcoat
- Suitable for: general warehouses, workshops, standard overseas environments
- Excellent weathering performance; sea-freight-safe
- Best cost-to-performance ratio
- The default specification for most export factory buildings and warehouses
Epoxy Zinc-Rich Primer + Acrylic Topcoat
- Lower material cost
- Suitable for inland locations with low corrosion risk
- Recommended for temporary or short-lifecycle structures
Epoxy Zinc-Rich Primer + Epoxy MIO Mid-coat + Fluorocarbon (PVDF) Topcoat
- Superior salt spray resistance and chemical resistance
- Designed for structures near the sea, in chemical processing zones, or tropical high-humidity regions
- Ideal for long-term outdoor performance in demanding climates
- Recommended for projects in Southeast Asia, the Middle East coast, Africa, and Pacific Island nations
Hot-Dip Galvanized to EN ISO 1461 / ASTM A123
- Applied to: C/Z purlins, bracing rods, tie rods, and light-gauge secondary members
- Metallurgically bonded zinc coating — no paint adhesion failure risk
- Stable long-term protection; ideal for thin-walled cold-formed sections
Summary
Effective corrosion protection is not a single step — it is an integrated process covering surface preparation, timely primer application, engineered multi-layer coating systems, targeted touch-up, and proper export packaging. Our factory applies these practices as standard for all export projects, ensuring that structures arrive at site in the same condition they left the factory.
For project-specific coating specifications, DFT (dry film thickness) requirements, or third-party inspection coordination, please contact our technical team.
