Q355NH (Chinese standard weathering steel): The minimum yield strength is >=355 MPa, which is 120 MPa higher than Q235NH. Q355NH is optimized for higher load-bearing scenarios, such as bridge support structures, high-rise building exterior frames, and heavy-duty outdoor guardrails, while Q235NH is more suitable for light structural components with moderate load requirements (e.g., landscape fences, low-rise building frames).
S355J2W (European standard weathering steel): Minimum yield strength >=355 MPa, equivalent to Q355NH. It has better low-temperature toughness than Q235NH, but in terms of yield strength, it is significantly higher, making it more applicable to structural projects with strict strength requirements.
ASTM A588 (American standard weathering steel): Minimum yield strength >=345 MPa, also higher than Q235NH. It is widely used in heavy outdoor structures in North America, and its strength advantage makes it more resistant to extreme wind and snow loads compared to Q235NH.
Q235 (ordinary carbon structural steel): Minimum yield strength is also 235 MPa, consistent with Q235NH. The core difference is not in strength, but in corrosion resistance-Q235NH contains Cu, Cr, Ni and other corrosion-resistant alloy elements, which can form a self-healing patina and achieve bare use outdoors, while Q235 must rely on regular anti-corrosion coating to avoid rapid rusting.
Q355 (ordinary high-strength carbon steel): Minimum yield strength >=355 MPa, higher than Q235NH. Q355 has better strength performance but lacks the inherent corrosion resistance of weathering steel, so it is more suitable for indoor structural applications or outdoor scenarios with frequent anti-corrosion maintenance.
Q195/Q215 (low-strength carbon steels): Their minimum yield strengths are 195 MPa and 215 MPa respectively, lower than Q235NH. These grades are mostly used for non-structural parts (e.g., steel pipes for fluid transportation, thin steel sheets for packaging), while Q235NH can bear light structural loads while having corrosion resistance, so it has a wider range of outdoor applications.
