Q295NH Weathering Steel
Q295NH is a Chinese standard weathering steel (GB/T 4171) offering enhanced atmospheric corrosion resistance. With higher strength than Q235NH, it is widely used in bridges, rolling stock, containers, and structural applications requiring improved load-bearing capacity.
Chemical Composition (heat analysis, %)
| Grade | C | Si | Mn | P | S | Cu | Cr | Ni | Others* |
|---|---|---|---|---|---|---|---|---|---|
| Q295NH | ≤0.15 | 0.10–0.50 | 0.30–1.00 | ≤0.030 | ≤0.030 | 0.25–0.55 | 0.40–0.80 | ≤0.65 | ①,② |
📌 Notes on chemical composition:
- ① Micro-alloying: may contain Nb (0.015–0.060%), V (0.02–0.12%), Ti (0.02–0.10%), Alt ≥0.020%. At least one element meets lower limit; total Nb+V+Ti ≤0.22%.
- ② Optional: Mo ≤0.30%, Zr ≤0.15% may be added by agreement.
- ③ Permissible deviations for product analysis according to GB/T 222. Sulphur can be agreed ≤0.008%.
- ④ Through negotiation, Ni lower limit may be waived, or C ≤0.15% (for Q295NH, C ≤0.15% is standard).
- ⑤ Smelting: converter or electric furnace, fully killed steel. Delivery states: hot-rolled / controlled-rolled / normalized (Q460NH–Q550NH may be quenched + tempered).
Mechanical Properties & Bending Test
| Grade | Lower yield strength ReL (≥ MPa) | Tensile strength Rm (MPa) | Elongation after fracture A/% ≥ | 180° Bending mandrel diameter |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤16 | >16-40 | >40-60 | >60 | N/mm² | ≤16 | >16-40 | >40-60 | >60 | ≤6 | >6-16 | >16 | |||
| Q295NH | 295 | 285 | 275 | 255 | 430 – 560 | 24 | 24 | 23 | 22 | a | 2a | 3a | ||
| 295/285/275/255 = Yield strength by thickness (MPa) 430-560 = Tensile strength range (MPa) a/2a/3a = Bending mandrel diameter (a = specimen thickness) | ||||||||||||||
Note: 'a' = specimen thickness. Rp0.2 applies if no yield plateau. Bending specimen width b=35mm for arbitration.
Smelting & Delivery Conditions
- 🔹 7.1.2 – Permissible deviations for product analysis per GB/T 222.
- 🔹 7.2 – Steelmaking: converter or electric furnace, fully killed. Method at supplier's option unless specified.
- 🔹 7.3 – Delivery: hot-rolled, controlled-rolled, normalized; Q460NH–Q550NH may be quenched + tempered. Cold-rolled sheets annealed.
- 🔹 Fabrication: Excellent weldability and cold forming. Preheating (100–150°C) recommended for thickness >25 mm.
🌉 Typical Applications & Properties
Q295NH forms a dense protective patina, eliminating the need for painting in many atmospheric environments. With higher strength than Q235NH, it is suitable for:
Available thickness: 2mm to 50mm. Mill test certificates (EN 10204 3.1) supplied.
© Q295NH technical data sheet — Based on GB/T 4171:2008 & amendments. Always verify with mill certificate.