Products Description
Q355GNHis a weathering steel grade defined under GB/T 4171, classified as an atmospheric corrosion-resistant low-alloy structural steel. It is designed to provide a balance of strength, atmospheric corrosion resistance, toughness, and weldability.
By alloying elements such as copper (Cu), chromium (Cr), nickel (Ni), phosphorus (P), and titanium (Ti), Q310GNH can develop a relatively stable protective oxide layer under suitable atmospheric exposure. The alloying elements contribute to the formation and densification of the weathering patina, which helps reduce further atmospheric corrosion compared with ordinary carbon steel.
For Q310GNH, the chemical composition should be controlled according to GB/T 4171. Typical/standard-reference ranges include C ≤0.12%, Si 0.25–0.75%, Mn 0.20–0.50%, P 0.070–0.120%, S ≤0.030%, Cu 0.25–0.55%, Cr 0.40–0.80%, and Ni ≤0.65%. The exact product chemistry should be verified against the applicable edition of GB/T 4171 and the material certificate.
The steel has a minimum yield strength of 310 MPa for thicknesses up to 16 mm, a tensile strength of approximately 450–680 MPa, and a minimum elongation of 26% under the applicable standard conditions. These properties make Q310GNH suitable for weathering structural applications where moderate strength and atmospheric corrosion resistance are required.
Its atmospheric corrosion resistance is often described as approximately 2–8 times that of ordinary carbon steel, while its coating-related performance is sometimes reported as 1.5–10 times better.
These figures are industry reference values rather than guaranteed material properties and can vary according to atmospheric exposure, steel composition, surface condition, coating system, and maintenance conditions.
Q310GNH steel plates can be used in railway vehicles, bridges, towers, containers, chimneys, storage tanks, and other atmospheric steel structures, provided that the grade, thickness, loading condition, and environmental exposure meet the project requirements. For relatively light-load structural applications, Q310GNH can provide a useful combination of strength, weathering resistance, and reduced coating requirements.
GB/T 4171 Q310GNH steel plate specification
Grade: Q310GNH
Standard: GB/T 4171
Thickness: 1 mm–100 mm
Width: 1000 mm–4100 mm
Length: 1000 mm–12000 mm
The above dimensions represent the product range stated for this page; actual available dimensions should be confirmed according to the applicable production and purchasing requirements.
Chemical Composition (Typical Values, %)
he following values should be treated as typical/standard-reference values. The final chemical composition should be checked against the applicable requirements of GB/T 4171 and the material test certificate.
| Grade | C | Si | Mn | P | S | Cu | Cr | Ni |
|---|---|---|---|---|---|---|---|---|
| Q310GNH | 0.12 | 0.25–0.75 | 0.20–0.50 | 0.07–0.12 | 0.02 | 0.20–0.50 | 0.30–1.25 | 0.65 |
These alloying elements help Q310GNH develop its characteristic weathering behavior. In particular, Cu, Cr, Ni and P contribute to the formation and stabilization of the protective rust layer during atmospheric exposure.
Mechanical Properties (Typical Values)
The key mechanical properties of Q310GNH include a minimum yield strength of 310 MPa for thicknesses up to 16 mm, tensile strength in the range of 450–680 MPa, and minimum elongation of 26% under the applicable standard conditions.
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation in 2 in. (50 mm) Min (%) |
|---|---|---|---|
| Q310GNH | 310 | 450 | 26 |
* The ≥310 MPa yield-strength value applies to the thickness range specified by the standard; for thicker products, the applicable GB/T 4171 requirement should be checked.
This combination of strength and ductility allows Q310GNH to be considered for structural components where atmospheric corrosion resistance is required without relying entirely on conventional protective coatings.
Q355GNH high weathering steel application
The weather resistance of Q355GNH high weathering steel is 2~8 times that of ordinary carbon steel, and the coating property is 1.5~10 times that of ordinary carbon steel.
At the same time, Q310GNH has characteristics including atmospheric corrosion resistance, long-term structural durability, reduced maintenance requirements, and potential savings in coating and maintenance work.
Weathering steel is mainly used in railways, vehicles, bridges, towers, and other steel structures exposed to the atmosphere for long periods. For Q310GNH specifically, application should be selected according to structural load, plate thickness, atmospheric environment, fabrication requirements, and the applicable design specification.
Q310GNH can also be considered for structural parts such as containers, railway vehicles, oil derricks, seaport buildings, and other atmospheric-exposed steel structures where its weathering characteristics are suitable. For chemical or petroleum equipment containing corrosive media, the actual material selection should be determined according to the specific medium, temperature, pressure, corrosion conditions, and applicable engineering requirements rather than assuming Q310GNH is suitable solely because it is weathering steel.
The previously stated around 400°C high-temperature application should be regarded as an experience/reference condition rather than a guaranteed temperature limit. Applications involving gas flues, exhaust systems, or other elevated-temperature environments require separate verification of the material's mechanical properties, oxidation behavior, design temperature, and applicable engineering standard.
