SHANGHAI RUICHAO INDUSTRIAL
SHANGHAI RUICHAO INDUSTRIAL
Weathering steel, often known by its trademark COR-TEN, is a high-strength, low-alloy steel specifically formulated to develop a stable, protective rust layer when exposed to the elements, eliminating the need for paint. Its defining characteristics are this adherent rust patina that inhibits further corrosion, high tensile strength, and excellent atmospheric corrosion resistance, typically 4 to 8 times that of ordinary carbon steel. Its primary use is in outdoor structural applications where durability and a specific aesthetic are desired, such as bridges, architectural building facades, sculptural art, and exposed shipping containers.
Specification Parameters
| Parameters of Weathering Steel | |||
| Parameter Category | Specific Parameter | Typical Value / Description | Importance for Weathering Steel Applications |
| Chemical Composition | Copper (Cu) | 0.25% - 0.55% | The most critical element. Initiates the formation of the protective patina and reduces corrosion rates. |
| Chromium (Cr) | 0.50% - 1.25% | Enhances atmospheric corrosion resistance by promoting the formation of a dense, protective oxide layer. | |
| Nickel (Ni) | 0.12% - 0.65% | Improves toughness and further enhances corrosion resistance, particularly in industrial atmospheres. | |
| Phosphorus (P) | 0.07% - 0.15% | Strengthens the patina and improves atmospheric corrosion resistance. Must be balanced with weldability. | |
| Silicon (Si) | 0.25% - 0.75% | Contributes to the formation of a dense, adherent rust layer. | |
| Carbon (C) | Low: < 0.12% - 0.19% | Kept low to maintain good weldability, toughness, and formability. | |
| Mechanical Properties | Yield Strength (YS) | 290 MPa (42 ksi) to 485 MPa (70 ksi) (e.g., ASTM A588 Grade A vs. Grade K) | Provides the structural strength required for load-bearing applications like bridges and buildings. |
| Tensile Strength (TS) | 415 MPa (60 ksi) to 655 MPa (95 ksi) | Must be sufficient for structural design requirements. | |
| Elongation | 18% - 22% (in 2 inches) | Ensures adequate ductility for fabrication and forming operations. | |
| Charpy V-Notch Impact Toughness | Often specified @ -34°C (-30°F) | Critical for structural applications to prevent brittle fracture in cold climates. | |
| Key Characteristics | Atmospheric Corrosion Resistance | 4x to 8x that of carbon steel (per ASTM G101) | The defining property. The stable, adherent rust patina acts as a barrier to further oxygen and moisture ingress. |
| Patina Formation | Develops over 3-6 years; color evolves from orange to deep brownish-purple | The aesthetic and functional outcome. The color and texture are design features. | |
| Environmental & Usage | Environment Suitability | Ideal: Rural, urban, and industrial atmospheres. | Requires alternating wet/dry cycles for the patina to form properly. Stagnant water or high chloride exposure will prevent passivation and cause accelerated corrosion. |
| Not Suitable: Constant moisture, saltwater splash zones, severe marine environments. | |||
| Governing Standards | Common Specifications | ASTM A588 (Most common), ASTM A606 (thin sheet/strip), ASTM A847 (for tubing) | These standards define the required chemical and mechanical properties for the steel to perform as intended. |
