1. Standard & Origin
Corten A: Complies with ASTM A242/A588 (American standard), a globally recognized weathering steel grade with strict international quality control.
Q355NH: Follows GB/T 4171-2008 (Chinese national standard), designed for domestic infrastructure and construction projects with regionally aligned specifications.
2. Chemical Composition (Key Alloy Differences)
Chromium (Cr): Corten A has a wider/higher range (0.40–1.25%) vs. Q355NH (0.40–0.80%)-enhances patina stability and corrosion resistance.
Phosphorus (P): Corten A (0.07–0.15%) vs. Q355NH (0.07–0.12%)-faster patina formation in Corten A.
Impurity Control: Corten A has stricter limits on sulfur (S) and oxygen (O), reducing localized corrosion risks. Q355NH allows more flexible impurity levels.
3. Corrosion Resistance
Corten A: Slightly superior, especially in moderately harsh environments (coastal areas, light industrial zones). Corrosion rate is 10–20% lower than Q355NH, with a more stable, self-renewing patina.
Q355NH: Reliable for mild environments (inland rural/suburban areas) but less durable in salt spray or industrial pollution. Patina forms slower (1.5–3 years vs. 1–2 years for Corten A).
4. Mechanical Properties
Corten A: Higher tensile strength (485–655 MPa) and yield strength (345 MPa min), suited for high-stress structural applications.
Q355NH: Yield strength (355 MPa min) matches its grade name, with balanced toughness-optimized for general structural loads in domestic projects.
5. Application Scope
Corten A: Globally used for high-demand projects-bridges, coastal infrastructure, international architectural facades, and long-service-life (30+ years) structures. Preferred for exports or projects requiring international certification.
Q355NH: Dominant in Chinese domestic projects-highway guardrails, inland buildings, warehouse frames, and short-to-medium lifespan (20–30 years) infrastructure. Leverages local supply chains and cost advantages.
