ASTM A588 Grade A, commonly referred to as weathering steel, is engineered to deliver outstanding atmospheric corrosion resistance.
Over time, a protective layer of iron oxide naturally forms on the surface, allowing it to be used without painting in many applications.
When corrosion protection is critical, ASTM A588 Grade A demonstrates approximately four times the corrosion resistance of conventional carbon steel. ASTM A588 is also produced in Grades B, C, and K, all of which are silicon-killed to ensure a uniform and consistent metallurgical structure.
Mechanical Properties (Grade A)
| Property | Metric | Imperial |
|---|---|---|
| Ultimate Tensile Strength | 400–550 MPa | 58,000–79,800 psi |
| Yield Strength | 250 MPa | 36,300 psi |
| Elongation at Break (200 mm) | 20% | 20% |
| Elongation at Break (50 mm) | 23% | 23% |
| Modulus of Elasticity | 200 GPa | 29,000 ksi |
| Bulk Modulus (typical for steel) | 140 GPa | 20,300 ksi |
| Poisson's Ratio | 0.26 | 0.26 |
| Shear Modulus | 79.3 GPa | 11,500 ksi |
Chemical Composition
Grade A
| Element | Content |
|---|---|
| C | 0.19% |
| Mn | 0.80–1.25% |
| P | 0.030% |
| S | 0.030% |
| Si | 0.03–0.65% |
| Ni | 0.40% |
| Cr | 0.40–0.65% |
| Cu | 0.25–0.40% |
| V | 0.02–0.10% |
Grade B
| Element | Content |
|---|---|
| C | 0.20% |
| Mn | 0.75–1.35% |
| P | 0.030% |
| S | 0.030% |
| Si | 0.15–0.50% |
| Ni | 0.50% |
| Cr | 0.40–0.70% |
| Cu | 0.20–0.40% |
| V | 0.01–0.10% |
Grade K
| Element | Content |
|---|---|
| C | 0.17% |
| Mn | 0.50–1.20% |
| P | 0.030% |
| S | 0.030% |
| Si | 0.25–0.50% |
| Ni | 0.40% |
| Cr | 0.40–0.70% |
| Mo | 0.10% |
| Cu | 0.30–0.50% |
| Nb | 0.005–0.05% |
