Q235NH Weathering Steel - Chemical Composition & Mechanical Properties
Technical specifications of Q235NH, a Chinese grade weathering steel for outdoor and industrial applications.
Q235NH Chemical Composition
Below is the chemical composition (quality fraction, in %) of Q235NH weathering steel, in accordance with relevant Chinese standards:
| Grade | Chemical Composition (Quality Fraction) / % | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | Cu | Cr | Ni | Others | |
| Q235NH | ≤0.13 | 0.1 ~ 0.4 | 0.2 ~ 0.6 | ≤0.03 | ≤0.03 | 0.25 ~ 0.55 | 0.4 ~ 0.8 | ≤0.65 | a, b |
Notes on Chemical Composition:
- ᵃ To improve the properties of steel, one or more trace alloying elements may be added: Nb 0.015%~0.060%, V 0.02%~0.12%, Ti 0.02%~0.10%, Alt ≥0.020%. When the above elements are used in combination, at least one element should be ensured to meet the lower limit of the above chemical composition.
- ᵇ The following alloying elements can be added: Mo≤0.30%, Zr≤0.15%.
- ᶜ The total amount of the three alloying elements Nb, V, and Ti added should not exceed 0.22%.
- ᵈ Through negotiation between the supplier and the buyer, the sulfur content may not exceed 0.008%.
- ᵉ Through negotiation between the supply and demand parties, a lower limit for Ni content may not be required.
- ᶠ Through negotiation between the supply and demand parties, the content of C may not exceed 0.15%.
Smelting & Delivery Status
- 7.1.2 The permissible deviations in the chemical composition of finished steel products shall comply with the provisions of GB/T 222.
- 7.2 Smelting methods: The steel is smelted in a converter or electric furnace and is killed steel. Unless otherwise specified by the buyer, the smelting method shall be selected by the supplier.
- 7.3 Delivery status: Hot-rolled steel is delivered in hot-rolled, controlled-rolled, or normalized condition. Steel grades Q460NH, Q500NH, and Q550NH can be delivered in quenched and tempered condition. Cold-rolled steel is generally delivered in annealed condition.
Q235NH Mechanical Properties & Processing Properties
Mechanical properties (tensile test and bending test) of Q235NH weathering steel, with thickness-based specifications:
| Grade | Tensile Test ᵃ | 180 °Bending test mandrel diameter | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lower yield strength ReL ≥ (MPa) | Tensile Strength Rm (MPa) | Elongation after fracture A/% ≥ | ||||||||||||
| ≤16mm | >16~40mm | >40~60mm | >60mm | ≤16mm | >16~40mm | >40~60mm | >60mm | ≤6mm | >6~16mm | >16mm | ||||
| Q235NH | 235 | 225 | 215 | 215 | 360 ~ 510 | 25 | 25 | 24 | 23 | a | a | 2a | ||
Note: 'a' represents the steel thickness.
When a yield plateau is not evident, Rp0.2 may be used.