What is the GB equivalent for the weathering steel grade EN S355J2W?

The GB equivalent for the weathering steel EN S355J2W is GB Q355NH, as per the standard GB/T 4171. Both are high-strength low-alloy steels with improved atmospheric corrosion resistance, forming a protective patina when exposed to weather. They have identical minimum yield strengths of 355 MPa. The "J2W" in the EN grade indicates specific impact toughness at -20°C and weathering resistance, which is matched by Q355NH's mandatory impact properties and corrosion index. Chemically, both achieve their weathering performance through alloying elements like Copper (Cu), Chromium (Cr), and Nickel (Ni). The specific ranges for these elements are aligned, though not perfectly identical. For applications like exposed bridges or architectural structures, Q355NH is a fully functional and accepted substitute for S355J2W, provided the corrosion resistance index specified in GB/T 4171 meets the project's design life requirements.