Q355GNH Chemical composition and mechanical properties of a Chinese grade weathering steel
Q355GNH Chemical Composition
| Grage | Chemical Composition(Quality Fraction)/% | |||||||||
| C | Si | Mn | P | S | Cu | Cr | Ni | others | ||
| Q355GNH | ≤0 .12 | 0 . 25 ~ 0 . 75 |
≤1.0 | 0 . 07 ~ 0 . 15 |
≤0 . 020 | 0 . 25 ~ 0 . 55 |
0 . 30 ~ 1.25 |
≤0.65 | a , b | |
| 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%. |
||||||||||
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.
Q355GNH Mechanical properties and processing properties
| Grade | Tensile Test a | 180 °Bending test mandrel diameter | ||||||||||||
| Lower yield strength ReL ≥ | Tensile Strength Rm |
Elongation after fracture A/%≥ | ||||||||||||
| ≤16 | >16 ~40 | >40 ~60 | >60 | ≤16 | >16~40 | >40~60 | >60 | ≤6 | >6 ~16 | >16 | ||||
| Q355GNH | 355 | 345 | - | - | 490 ~ 630 | 22 | 22 | - | - | a | 2a | 3a | ||
Note: 'a' represents the steel thickness.
When a yield plateau is not evident, Rp0.2 may be used.