Q235NH weathering steel section is a high - performance material designed for bridge and construction applications. It combines unique properties to offer long - term reliability in challenging environments.
Chemical Composition
The chemical composition of Q235NH is carefully formulated. Carbon content is limited to 0.13% maximum, which helps maintain good weldability. Silicon (Si) ranges from 0.10 - 0.40%, enhancing oxidation resistance. Manganese (Mn) at 0.20 - 0.60% improves strength and workability. Phosphorus (P ≤ 0.030%) and sulfur (S ≤ 0.030%) are strictly controlled to prevent embrittlement. The addition of copper (Cu) at 0.25 - 0.55%, chromium (Cr) at 0.40 - 0.80%, and nickel (Ni ≤ 0.65%) forms a protective patina that shields the steel from corrosion.
Mechanical Properties
Q235NH weathering steel section has a yield strength of 235 MPa, ensuring it can bear significant loads. Its tensile strength is in the range of 360 - 510 MPa, providing resistance to deformation under stress. The elongation is at least 24%, indicating good ductility for forming and bending processes during construction.
FAQ
1. What is Q235NH weathering steel section designed for?
Answer: It is designed for bridge and construction applications, offering long-term reliability in challenging environments.
2. Which standard does Q235NH comply with?
Answer: The material complies with GB/T 4171-2008 (implied by previous context, as Q235NH is consistently referenced under this standard).
3. What key alloy elements form the protective patina in Q235NH?
Answer: Copper (Cu 0.25–0.55%), chromium (Cr 0.40–0.80%), and nickel (Ni ≤ 0.65%) collaborate to form the self-healing oxide layer (patina).
4. What are the mechanical properties of Q235NH?
Answer:
Yield strength: 235 MPa (ensures load-bearing capacity)
Tensile strength: 360–510 MPa (resists deformation under stress)
Elongation: ≥24% (enables ductility for forming/bending during construction).
5. How does carbon content affect Q235NH's performance?
Answer: The carbon content is limited to ≤0.13%, which maintains good weldability and core structural strength without compromising the material's ductility or corrosion resistance.
