SPA‑H and SPA‑C are both common weathering steels, but they belong to different performance grades and are designed for different application scenarios.
1. Main difference in positioning
SPA‑H: High‑performance weathering steel, for long‑term outdoor structures (buildings, bridges, outdoor equipment).
SPA‑C: Commercial / container‑grade weathering steel, mainly for shipping containers and general structural parts.
2. Corrosion resistance
SPA‑H: Higher alloy content (Cu, Cr, Ni, P) → forms denser, more stable patina → much better corrosion resistance.
SPA‑C: Basic weather resistance, good enough for containers, but lower than SPA‑H in long‑term durability.
3. Surface & patina quality
SPA‑H: Patina is uniform, stable, less powdering and rust runoff → suitable for visible architectural facades.
SPA‑C: Patina forms faster but is more likely to be uneven in early stages.
4. Mechanical properties
SPA‑H: Higher strength and toughness, better for structural components.
SPA‑C: Focus on good weldability and formability for container manufacturing.
5. Typical applications
SPA‑H: Building facades, bridges, landscape sculptures, outdoor engineering structures.
SPA‑C: Shipping containers, railway wagons, truck bodies, general structural parts.
6. Cost
SPA‑H: Higher cost (better performance).
SPA‑C: Lower cost (mass production for containers).
