Weathering Steel Grade Systems
Weathering (atmospheric corrosion resistant) steels are produced to several national standard systems. The main grade families are: GB/T 4171 in China (Q235NH–Q550NH, including the high-phosphorus GNH series), EN 10025-5 in Europe (S235J0W–S355K2W, including the WP high-phosphorus grades), ASTM A588/A242/A606 in the US, and JIS G3125 (SPA-H, SPA-C) and JIS G3114 (SMA series) in Japan. All rely on the same mechanism: alloying elements (copper, chromium, nickel, phosphorus) promote a dense, adherent protective rust layer.
| Corten Steel Plate Specification | |
| Standard Grade |
ASTM: Corten A; Corten B; A588Gr.A/Gr.B/Gr.C/ Gr.K; A242; A606 Type 4; A709 Gr 50W; EN10025: S235J0W; S235J2W; S355J0W; S355J2W; S355K2W; S355J0WP; S355J2WP; S355J2G1W; S355J2G2W; S355K2G1W, S355K2G2W; JIS G3114: SMA400AW; SMA400BW; SMA400CW; SMA490AW; SMA490BW; SMA490CW; SMA570W; SMA570P; JIS G3125: SPA-H; SPA-C; GB/T 4171: Q235NH; Q265GNH; Q310GNH; Q295NH; Q295GNH; Q355NH; Q355GNH; Q415NH; Q460NH; 1500NH; Q550NH; TB/T 1979: 09CuPCrNi-A; 09CuCrNi-B; 05CuPCrNi; Q/BQB 340: B460NQR; B490NQR; B480GNQR; B600GNQR; |
| Thickness | Cold Rolled 0.5-2mm Hot Rolled 2-300mm (2-100mm usually used) |
| Width | 1000-3000mm (1000-2200mm usually used) |
| Length | 1000-12000mm or as your request |
| Surface | Clean, finishing,blasting and painting according to customer requirement |
| Delivery States |
Hot-rolled, Controlled rolling, Normalizing, Annealing, Tempering, Quenching, N+T, Q+T,and other delivery states are available as required |
| Certificate | API,ISO,SGS,BV,CE etc |
| Quality | MTC will be provided with goods, third part inspection is acceptable, for example BV,SGS. |
| Package | Standard export seaworthy package,suit for all kinds of transport, or as required. |
| Container Size |
20ft GP:5898mm(Length)x2352mm(Width)x2393mm(High) |
| 40ft GP:12032mm(Length)x2352mm(Width)x2393mm(High) | |
| Trade term | Ex-Work,FOB,CNF,CFR,CIF,etc |
| Application | Widely used in a variety of architectural and engineering structures,such as 1.) metal constructions such as buildings,bridges,ships; 2.) transmission tower, reaction tower; 3.) lifting transportation machinery; 4.) industrial furnace;boilers 5.) container frame, warehouse goods shelves, etc |
Chemical Composition and Mechanical Properties:
| Element | Q295NH | Q355NH | S235J0W | A588 Gr.B | SPA-H |
|---|---|---|---|---|---|
| Carbon (C) | ≤ 0.15 | ≤ 0.16 | ≤ 0.13 | ≤ 0.20 | ≤ 0.12 |
| Silicon (Si) | 0.10–0.50 | ≤ 0.50 | ≤ 0.40 | 0.15–0.50 | 0.20–0.75 |
| Manganese (Mn) | 0.60–1.00 | 0.50–1.50 | ≤ 1.00 | 0.75–1.35 | ≤ 0.60 |
| Phosphorus (P) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 | ≤ 0.040 | 0.070–0.150 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 | ≤ 0.050 | ≤ 0.035 |
| Chromium (Cr) | 0.40–0.80 | 0.40–0.80 | 0.40–0.80 | 0.40–0.70 | 0.30–1.25 |
| Copper (Cu) | 0.25–0.55 | 0.25–0.55 | 0.25–0.55 | 0.20–0.40 | 0.25–0.55 |
| Nickel (Ni) | ≤ 0.65 | ≤ 0.65 | ≤ 0.65 | ≤ 0.50 | ≤ 0.65 |
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Impact |
|---|---|---|---|
| Q295NH | ≥ 295 | 430–560 (per edition) | Per order |
| Q355NH | ≥ 355 | 490–630 (per edition) | Per order |
| S235J0W | ≥ 235 | 360–510 (per edition) | 27 J at 0 °C |
| A588 Gr.B | ≥ 345 | 485–620 | Per order |
| SPA-H | ≥ 355 | ≥ 490 | Per order |
Selection Logic
GB/T 4171 Q series: for projects specified to the Chinese system (Q295NH for medium loads, Q355NH for higher loads).
EN 10025-5 S series: for European projects; J0W (0 °C) and J2W (-20 °C) impact classes available.
ASTM A588: for US-specified structures, shapes and plates up to heavy thicknesses.
JIS SPA-H: for Japanese-specified projects and thinner products.
FAQ
Q: Is Corten steel magnetic?
A: Yes - like most steels (except austenitic stainless), weathering steel is magnetic.
Q: What is the weakness of weathering steel?
A: The patina formation is somewhat unpredictable, initial rust runoff can stain adjacent surfaces, and it is not suitable for permanently wet or high-chloride environments without protection.
Q: Can weathering steel be painted?
A: Yes - painting provides a uniform appearance for projects where the weathered look is not suitable.
Q: Can weathering steel hold water?
A: It is strong and water-resistant; however, water bowls and water features continue to rust inside, discoloring the water - refresh the water at intervals or apply a protective coating inside.
About Gnee
Founded in 2008, Gnee (Tianjin) Supply Chain Group Co., Ltd. specializes in the global trade and processing of Corten steel products.
• We handle all kinds of Corten engineering projects, such as bridges, gardens, hotels, and facade systems.
• Compliant with ASTM, EN, and other international standards; third-party inspection supported.
• Exported to over 200 countries and regions worldwide.
• 8 subsidiaries across China and overseas, ensuring global service coverage.
Application Fields: Architecture, landscaping, gardening, cladding, and urban infrastructure.
