Q295GNH and Q295NH are both Chinese weathering (Corten) steels with the same minimum yield strength (295 MPa), but Q295GNH is a specific grade under GB/T 4171 for atmospheric corrosion, containing controlled Copper, Chromium, Nickel, etc., forming a stable rust layer for better protection, while Q295NH is a more general weathering steel grade often referring to similar low-alloy structural steels with good atmospheric corrosion resistance for applications like containers, buildings, and bridges, though Q295GNH emphasizes its specific Corten properties. The 'G' in Q295GNH usually denotes its weathering capability, making Q295GNH a more precise name for Corten-type steel.
Chemical Composition of Q295GNH Steel Plate
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Q295GNH Chemical composition |
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|
Grade |
The Element Max (%) |
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|
Q295GNH
|
C |
Si |
Mn |
P |
S |
|
≤0.12 |
0.20-0.40 |
0.20-0.60 |
0.07-0.15 |
≤0.035 |
|
|
Cr |
Cu |
Ti |
RE |
|
|
|
|
0.25-0.55 |
≤0.10 |
≤0.15 |
|
|
Chemical Composition of Q295NH Steel Plate
|
Element |
Content (%) |
|---|---|
|
Carbon (C) |
≤ 0.15 |
|
Silicon (Si) |
0.10 - 0.40 |
|
Manganese (Mn) |
0.30 - 1.00 |
|
Phosphorus (P) |
≤ 0.035 |
|
Sulfur (S) |
≤ 0.035 |
|
Chromium (Cr) |
0.30 - 1.25 |
|
Nickel (Ni) |
≤ 0.65 |
|
Copper (Cu) |
0.25 - 0.55 |
Mechanical Properties of Q295GNH Steel Plate
|
Grade |
Thickness |
Yield |
Tensile |
Elongation |
Delivery state |
|
Q295GNH
|
mm |
Min Mpa |
Mpa |
Min % |
|
|
≤6 |
295 |
390 |
24 |
Hot rolling |
|
|
>6 |
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|
≤2.5 |
260 |
390 |
27 |
Cold rolling |
Mechanical Properties of Q295NH Steel Plate
| Grade | Yield Strength(MPa) | Tensile Strength(MPa) | % Elongation min |
| GB/T 4171 Q295NH | 255-295 | 430-560 | 22 |
Key Differences Explained:
Q295GNH (GB/T 4171):
Type: Specific Corten (Weathering) Steel.
'G': Signifies "Guang" (weathering/exposure) or similar, indicating its self-protecting rust layer.
Composition: Controlled amounts of Cu, Cr, Ni, P, etc., to develop a dense, stable oxide patina.
Use: Bridges, building facades, sculptures, where aesthetics and long-term atmospheric protection are key.
Q295NH:
Type: Weather Resistant Structural Steel.
'NH': Also indicates weathering/atmospheric corrosion resistance.
Composition: Low alloy, similar elements to Q295GNH for corrosion resistance.
Use: Trucks, shipping containers, towers, general structures needing atmospheric corrosion protection.
In essence, while both are weathering steels: Q295GNH is the more common and precisely defined Corten grade under GB/T 4171, highlighting its exceptional protective rust layer compared to general weathering steels like Q295NH.
