S355J2W steel (1.8965): properties, composition, equivalents
S355J2W (1.8965) is the European Corten B: Cu-Cr-Ni weathering steel, 355 MPa yield, 470–630 MPa tensile, 27 J at −20 °C, self-protecting rust patina. Chemistry, thickness table, A588 / A242 / SMA490 equivalents, welding and façade use.
What is S355J2W?
S355J2W is the weathering structural steel of EN 10025-5 — the grade Europe buys when the drawing says Corten B (the ArcelorMittal/US Steel trade name) or the old German WTSt52-3. A copper-chromium-nickel addition (Cu 0.25–0.55, Cr 0.40–0.80, Ni ≤ 0.65 %) makes the rust that forms in wet-dry cycles dense and adherent instead of flaky, so an unpainted bridge girder, façade panel, chimney or sculpture stabilises at a 0.1–0.2 mm patina and then corrodes at a tenth of the rate of plain carbon steel. Werkstoff number 1.8965. The mechanical table is that of S355J2: 355 MPa yield, 470–630 MPa tensile, 27 J at −20 °C.
The patina needs alternating wet and dry exposure; permanently damp details, chloride-rich coastal air (> 2 km from the sea is the usual limit), and sheltered crevices do not form it and corrode as ordinary steel. Design details therefore avoid water traps, and run-off is managed because early rust stains concrete and glass. Thin façade sheet (1.5–3 mm) is delivered pre-rusted or blasted; plate for bridges is normally +N.
ASTM A588 Grade A/B is the direct US equivalent; A242 and A606 Type 4 cover the thin, phosphorus-bearing variants (EN S355J2WP); JIS SMA490 and GB Q355NH are the Asian counterparts.
S355J2W chemical composition
| Element | Mass % | Note |
|---|---|---|
| C | ≤ 0.16 | |
| Si | ≤ 0.5 | |
| Mn | 0.5 – 1.5 | |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Cr | 0.4 – 0.8 | |
| Cu | 0.25 – 0.55 | |
| Ni | ≤ 0.65 | |
| Mo | ≤ 0.3 | |
| Zr | ≤ 0.15 |
Ladle analysis, EN 10025-5:2019 Table 2. Fully killed; N ≤ 0.009 unless Al-bound. Copper and chromium (with nickel) form the dense, adherent oxide layer; the WP variants (S355J0WP/J2WP) instead use P 0.06–0.15 % and are limited to ≤ 12 mm. CEV max 0.52 % (≤ 16 mm).
S355J2W mechanical properties
| Thickness / condition | Yield strength ReH / Rp0.2 MPa (ksi) | Tensile strength Rm MPa (ksi) | Elongation A % | Hardness |
|---|---|---|---|---|
| ≤ 16 mm | 355 (51.5) | 470–630 (68.2–91.4) | 22 | ≈ 150–190 HB (typ.) |
| > 16 ≤ 40 mm | 345 (50.0) | 470–630 (68.2–91.4) | 22 | — |
| > 40 ≤ 63 mm | 335 (48.6) | 470–630 (68.2–91.4) | 21 | — |
| > 63 ≤ 80 mm | 325 (47.1) | 470–630 (68.2–91.4) | 20 | — |
| > 80 ≤ 100 mm | 315 (45.7) | 470–630 (68.2–91.4) | 20 | — |
| > 100 ≤ 150 mm | 295 (42.8) | 450–600 (65.3–87.0) | 18 | — |
EN 10025-5:2019 Table 4 — identical strength table to S355J2 (EN 10025-2). Elongation longitudinal, L0 = 5.65√S0; transverse values 2 points lower.
Impact toughness
S355J2W requires a minimum Charpy V-notch energy of 27 J at -20 °C (longitudinal). S355J0W: 27 J at 0 °C; S355K2W: 40 J at −20 °C. J2W is the usual bridge and structural ordering grade.
S355J2W equivalent grades
| Grade | System | Match | Why / differences |
|---|---|---|---|
| A588 Grade A / B | ASTM / ASME | Near | ASTM A588: 345 MPa yield, 485 MPa tensile, Cu-Cr-Ni(-V) weathering steel for bridges — the US Corten B; Grade A is Cr-rich, Grade B Ni-rich, both within S355J2W chemistry ranges. |
| S235J2W | EN (European) | Near | Lower-strength weathering grade (235 MPa) for façades and non-critical members. |
| Q355NH | GB/T (China) | Near | GB/T 4171 weathering structural steel, 355 MPa yield; Q355NH (Cu-Cr-Ni) ≈ S355J2W, Q355GNH ≈ WP type. |
| 10ХНДП / 14ХГНДЦ | GOST (Russia/CIS) | Near | GOST 19281 weathering (Cu-Ni-P and Cu-Cr-Ni) structural steels of 345–355 MPa class. |
| SMA490BW / CW | JIS (Japan) | Near | JIS G3114 welded structural weathering steel, 355 MPa yield (≤ 16 mm), 490–610 MPa tensile; B = 0 °C, C = −5 °C impact. |
| A242 Type 1 | ASTM / ASME | Functional | ASTM A242: the original Cu-P weathering steel (345 MPa ≤ 19 mm) — closer to S355J2WP; used for sheet and light sections. |
| A606 Type 4 | ASTM / ASME | Functional | ASTM A606 Type 4 sheet and strip with enhanced corrosion resistance (345 MPa) — the thin-gauge façade equivalent. |
| S355J2 | EN (European) | Functional | Same mechanical properties without the weathering alloying — use where the steel is painted or galvanized. |
Identical = same composition and mechanical limits within rounding. Near = one limit differs (e.g. carbon max or impact temperature). Functional = interchangeable for most uses after an engineering check. Full cross-reference for S355J2W →
Old and superseded designations
| Old name | Standard | Note |
|---|---|---|
| WTSt52-3 | DIN 17100 / SEW 087 | German weathering structural steel; direct predecessor. |
| S355J2G1W / S355J2G2W | EN 10155:1993 | G1 = as-rolled, G2 = normalized; merged into S355J2W in EN 10025-5:2004. |
| Fe510D2K1 | EN 10155:1993 (Fe designation) | |
| WR50B / WR50C | BS 4360 | British weathering grades. |
Product forms and tolerance standards
Product forms: hot-rolled plate 2–150 mm (+AR or +N), hot-rolled coil and sheet 1.5–12 mm (façade and cladding), sections, flats and bar, hollow sections as S355J2WH (EN 10219/10210).
Dimensional tolerances: plate: EN 10029 class A, flatness N; coil/sheet: EN 10051; sections: EN 10034 / EN 10279.
Key property values
S355J2W yield strength
≥ 355 MPa (51 ksi) up to 16 mm, stepping down to 295 MPa at 150 mm — same table as S355J2.
S355J2W tensile strength
470–630 MPa (68–91 ksi) up to 100 mm; 450–600 MPa above.
S355J2W elongation
≥ 22 % (longitudinal, ≤ 40 mm); 18 % at 150 mm.
Impact toughness
27 J at −20 °C (Charpy V, longitudinal). Order S355K2W for 40 J at −20 °C.
Corrosion rate
After patina formation (1–3 years, C2–C3 atmospheres): about 5 µm/year vs 30–50 µm/year for unprotected S355J2; EN 1993-1-1 / EN 1993-2 allow a 1 mm per exposed face corrosion allowance over 100 years in suitable environments. Not for permanently wet, buried, marine (C5) or de-icing-salt-splashed positions without paint.
Physical properties
Density 7.85 g/cm³, E = 210 GPa, thermal expansion 12 × 10⁻⁶/K — identical to carbon structural steel.
Weldability
Weldable by all arc processes with the same preheat rules as S355J2 (CEV ≤ 0.52; preheat 50–100 °C above ~25 mm combined thickness). For exposed welds use matching weathering consumables (e.g. EN ISO 2560 E 42 4 Z B / AWS E8018-W2, or Cu-Ni-bearing wires) so the weld patinates with the plate; for painted or multi-pass root runs, ordinary S355 consumables are acceptable except the cap. Remove mill scale beside the weld for uniform patina.
Machining, forming and heat treatment
Cut by plasma, laser and oxy-fuel as S355; the Cr-Cu content slightly increases tool wear when drilling. Cold bending radius ≥ 2 t (plate) / 1.5 t (sheet); hot forming 850–1 100 °C. Blasting to Sa 2½ before exposure gives an even patina; pre-weathering (accelerated rusting) is offered for façade sheet.
Typical applications
- Highway and railway bridges (unpainted girders, cross-beams)
- Building façades, cladding and screens in pre-weathered sheet
- Transmission and lighting towers, masts, guardrail
- Chimneys, silos, hoppers, conveyor structures
- Shipping containers (thin A606/S355J2WP-type sheet)
- Sculpture, landscape and garden elements
- Rail wagons and truck bodies (with S355J2WP)
Frequently asked questions
Is S355J2W the same as Corten B?
For specification purposes yes: Corten B is a trade name; its chemistry and 345–355 MPa yield fall within ASTM A588 Grade A/B and EN 10025-5 S355J2W. Corten A is the phosphorus type, closer to S355J2WP / A242.
How long does weathering steel take to form its patina?
Typically 1–3 years in a temperate C2–C3 atmosphere with wet-dry cycling; faster with pre-weathering treatment. During that period rust run-off can stain adjacent surfaces.
Can S355J2W be used near the sea?
Not unpainted within about 2 km of the coast or where de-icing salt is splashed: chlorides prevent a stable patina and the steel corrodes like ordinary S355. Paint it or choose stainless there.
Does weathering steel need painting?
No, that is its purpose — but details must drain, avoid crevices and allow drying. Painted weathering steel still benefits: coating life is longer because under-film corrosion is slower.
What is the difference between S355J2W and S355J2WP?
J2W is the Cu-Cr-Ni type for all thicknesses (bridges, plate); J2WP is the Cu-P type (P 0.06–0.15 %) limited to ≤ 12 mm, mainly sheet for façades and containers, with slightly better patina but poorer weldability in thick sections.
What welding consumable for S355J2W?
Matching weathering-grade consumables (AWS E8018-W2 / EN ISO 2560 with Cu-Ni) for exposed cap passes; standard S355 consumables are acceptable for root and fill or where the joint will be painted.
Related grades
Verified against EN 10025-5:2019; EN 10025-5:2019 Tables 2, 4 and 5; EN 10025-1:2019 (general delivery conditions); EN 1993-1-1 / EN 1993-2 (corrosion allowance); ASTM A588/A588M-19, ASTM A242/A242M-13; JIS G3114:2016. Last checked: September 2026.