Comparison of Equivalent Grades for S355K2G2W Weathering Steel Plates

Trying to substitute S355K2G2W with another standard? Here's how it maps across major systems.

The origin. S355K2G2W comes from the old European standard EN 10155 (now superseded by EN 10025-5, where it appears as S355K2W with material number 1.8967). The "G2" indicates a specific phosphorus range for enhanced corrosion resistance.

ASTM. The closest match is ASTM A588 Grade A/B or A709-50W for bridge applications. Both offer similar yield strength and weathering chemistry.

JIS (Japan). JIS G3114 SMA490AW or SMA570W are the nearest equivalents. Note that standard SMA490 grades test impact at 0°C, not -20°C, so verify low-temperature performance if needed.

GB (China). The direct equivalent is Q355NH per GB/T 4171. For structural plates, Q355D (GB/T 1591) can also work, as it matches the 355 MPa yield and -20°C impact requirement.

BS (UK, withdrawn). WR50 series from the old BS 4360 standard was the historical counterpart.

One caution. Always verify impact toughness and phosphorus content when substituting. The "K2" and "G2" suffixes carry specific guarantees that not all equivalents replicate exactly.