| Feature | Weathering Steel (e.g., ASTM A588, Corten) | Stainless Steel (e.g., 304, 316) |
|---|---|---|
| Corrosion Resistance | Forms a protective rust layer (patina) that slows further corrosion. Not suitable for high-salinity or acidic environments. | Naturally resists rust due to chromium oxide layer. Ideal for harsh/coastal/chemical environments. |
| Appearance | Rusty, earthy aesthetic (used in architecture). Color stabilizes over time. | Sleek, metallic finish (silver/gray). Remains unchanged. |
| Strength | High tensile strength (structural applications). Stronger than standard stainless grades. | Moderate strength (304: ~515 MPa yield). Can be hardened via alloys. |
| Cost | Lower (~1,000–1,000–1,500/ton). Saves long-term maintenance costs. | Higher (~2,500–2,500–4,000/ton for 304). Premium for corrosion resistance. |
| Maintenance | Minimal (once patina forms). May require initial runoff management. | Low (occasional cleaning). No rust to manage. |
| Welding/Fabrication | Requires compatible techniques to avoid brittleness. Pre-rust removal needed. | Easier but needs controlled heat input. No pre-cleaning rust. |
| Common Uses | Bridges, outdoor sculptures, warehouse facades. Exposed structural projects. | Kitchen equipment, marine hardware, medical devices. Hygienic/corrosive environments. |
