The primary ASTM standards for weathering steel include:
1. ASTM A588
"Standard Specification for High-Strength Low-Alloy Structural Steel with 50 ksi [345 MPa] Minimum Yield Point"
Most common weathering steel grade (e.g., A588 Gr. A/B/C/K).
Forms a protective rust patina, used in bridges, towers, and outdoor structures.
2. ASTM A242
"Standard Specification for High-Strength Low-Alloy Structural Steel"
Early weathering steel variant (e.g., A242 Type 1), with similar corrosion resistance but slightly different mechanical properties.
3. ASTM A606 (Type 4)
"Standard Specification for Steel, Sheet and Strip, High-Strength, Low-Alloy, Hot-Rolled and Cold-Rolled, with Improved Atmospheric Corrosion Resistance"
Used for thinner sheets/strips (e.g., architectural cladding).
4. ASTM A847
"Standard Specification for Cold-Formed Welded and Seamless High-Strength, Low-Alloy Structural Tubing with Improved Atmospheric Corrosion Resistance"
For hollow structural sections (HSS) in corrosive environments.
Key Feature of All:
Contain alloying elements (Cu, Cr, Ni, P) to form a self-protecting rust layer (patina), eliminating the need for painting in most environments.
