S355J2W is a high-performance steel that combines high weather resistance, high strength and excellent low-temperature toughness. Its unique ‘rust-stops-rust’ mechanism makes it an ideal choice for numerous outdoor steel structure applications where long service life and low maintenance costs are sought. The key points for its design and use in outdoor structures are as follows:

1. Structural Design

Ventilation and drainage must be unobstructed; water accumulation, dust build-up and dampness trapped in crevices must be strictly avoided.

Direct contact with ordinary carbon steel or stainless steel must be avoided to prevent galvanic corrosion.

2. Surface Condition

For exposed outdoor use: Do not apply ordinary paint; allow a dense rust layer to form naturally.

In coastal or industrial areas with severe corrosion: Apply a specialised weathering primer followed by a topcoat.

3. Temperature Suitability

J2 Impact: -20°C ≥27J, suitable for outdoor structures in cold regions.

For temperatures below -20°C, a higher grade (e.g. K-grade, NL-grade) should be selected.

4. Joining and Welding

Use welding rods or wires specifically designed for weathering steel.

The welded areas must possess the same weathering resistance as the base material to prevent premature corrosion.