ASTM A871 — High-strength low-alloy weathering steel plate
Grades
Gr.60, Gr.65, Gr.70
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| Gr.60 | C≤0.26, Mn≤1.35, P≤0.040, S≤0.050, Nb+V 0.01-0.15 | Rm ≥520 MPa, Rp0.2 ≥415 MPa, A≥18% |
| Gr.65 | C≤0.23, Mn≤1.65, P≤0.040, S≤0.050, Nb+V 0.01-0.15 | Rm ≥550 MPa, Rp0.2 ≥450 MPa, A≥17% |
| Gr.70 | C≤0.20(>50mm≤0.22), Mn 1.00-1.50(>50mm1.10-1.60), Si 0.15-0.40, P≤0.025, S≤0.025 | Rm 485-620 MPa, Rp0.2 ≥260 MPa, A≥19%, Normalizing |
Application scope
ASTM A871 specifies high-strength, low-alloy weathering steel plates for atmospheric applications, available in three strength grades: Gr.60, Gr.65, and Gr.70. Suitable for welded and bolted tower structures. Utilizing niobium, vanadium microalloying, and elements such as copper, it achieves both high strength and resistance to atmospheric corrosion. Some grades are delivered normalized. The products can be used bare, reducing the need for painting, making them suitable for maintenance-free outdoor structures.
Typical applications
Primarily used for the tower bodies and crossarms of power transmission towers, communication towers, and microwave towers, as well as for pole structures such as road lighting poles, monitoring poles, and signal supports. Due to its high strength and resistance to atmospheric corrosion, it is also used for long-term exposed components such as outdoor equipment housings, enclosures, guardrails, and support frames. Suitable for applications with large loads, high vertical structures, inconvenient maintenance, and where reduced painting burden is required.
