Q265GNH and Q345GNH are Chinese standard (GB/T) weather-resistant (COR-TEN type) low-alloy structural steel plates, known for their enhanced corrosion resistance, high strength, and good weldability, commonly used in bridges, vehicles, containers, and offshore structures, with "Q" indicating yield strength, "345" its minimum yield strength (345 MPa for Q345, ~265 MPa for Q265), and "NH" signifying they are weather-resistant grades suitable for corrosive environments.
Chemical composition of Q265GNH steel plate
|
Grade |
Q265GNH steel chemical composition(%) |
||||
|
C Max |
Si |
Mn |
P |
S Max |
|
|
China GB/T 4171 Q265GNH |
0.12 |
0.1-0.4 |
0.2-0.5 |
0.07-0.12 |
0.02 |
Chemical composition of Q345GNH steel plate
|
Q345GNH Chemical composition |
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|
Grade |
The Element Max (%) |
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|
Q345GNH
|
C |
Si |
Mn |
P |
S |
|
≤0.12 |
0.25-0.75 |
0.20-0.50 |
0.07-0.15 |
≤0.035 |
|
|
Cr |
Cu |
Ni |
RE |
|
|
|
0.30-1.25 |
0.25-0.55 |
≤0.65 |
|
|
|
Mechanical property of Q265GNH steel plate
|
Grade |
Q265GNH steel mechanical property |
|
|
|
Yield Strength(MPa) min |
Tensile Strength(MPa) min |
% Elongation min |
|
|
China GB/T 4171 Q265GNH |
265 |
410 |
-- |
Mechanical property of Q345GNH steel plate
|
Grade |
Thickness |
Yield |
Tensile |
Elongation |
Delivery state |
|
Q345GNH
|
mm |
Min Mpa |
Mpa |
Min % |
|
|
≤6 |
345 |
480 |
22 |
Hot rolling |
|
|
>6 |
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|
≤2.5 |
320 |
450 |
26 |
Cold rolling |
Key Characteristics
Weathering Resistance: These steels form a stable, protective rust layer (patina) when exposed to weather, reducing the need for painting and maintenance, similar to ASTM A588 (COR-TEN B).
High Strength: They offer higher strength than basic carbon steels.
Weldability: Good weldability for fabrication.
Applications: Ideal for outdoor structures like bridges, railway cars, towers, architectural features, and oil & gas equipment where corrosion is a concern.
