Q355NH vs. Q355GNH: Differences and Applications

Differences

Q355NH and Q355GNH are both weathering steels with similar atmospheric corrosion resistance, but they differ in their standards and specific applications. Q355NH is defined under the Chinese standard GB/T 4171, while Q355GNH follows the GB/T 4172 standard. The primary distinction lies in their chemical composition and mechanical properties. Q355GNH typically has slightly higher amounts of alloying elements like copper, chromium, and nickel, enhancing its corrosion resistance and strength compared to Q355NH.

Applications

Q355NH: Commonly used in structural applications such as bridges, railway vehicles, and transmission towers, where moderate strength and weather resistance are required. It is suitable for environments with less severe corrosion conditions.

Q355GNH: Ideal for more demanding applications, including architectural facades, outdoor sculptures, and industrial equipment exposed to harsh weather. Its superior corrosion resistance and aesthetic rust-like appearance make it a preferred choice for projects requiring durability and low maintenance.

Conclusion

While both Q355NH and Q355GNH offer excellent weathering properties, Q355GNH is better suited for high-corrosion environments and aesthetic applications, whereas Q355NH is more commonly used in general structural projects. The choice depends on the specific requirements of the project and environmental conditions.