What is S355J2WP corten sheet?
S355J2WP is defined by EN 10025-5 (structural steels with improved atmospheric corrosion resistance): S structural, 355 MPa yield, J2 for 27 J Charpy at −20 °C, W for weathering, P for the phosphorus-alloyed variant. Material number 1.8946. Its chemistry — copper 0.25–0.55 %, chromium 0.30–1.25 %, phosphorus deliberately raised to 0.06–0.15 %, plus nickel — is that of the original US Steel Cor-Ten A of 1933, and ASTM A242 is its closest American relative. When the surface wets and dries in cycles, those elements make the rust layer dense, adherent and amorphous rather than porous and flaky; after 6–18 months of exposure the patina stabilises at the deep orange-brown that then darkens to chocolate, and corrosion slows to a few micrometres a year — 4–8 times slower than plain steel, with no paint ever. The phosphorus that gives the best patina also limits the grade: it is restricted to 12 mm and welds need care, which is why S355J2WP is a *sheet* product for façades, cladding, screens, planters, edging, sculptures, fire bowls and signage, while the lower-phosphorus S355J2W (Corten B) is the plate grade for bridges and structures. It needs wet-dry cycling to work — permanently damp, buried, submerged or chloride-laden marine exposure does not form the patina and the steel simply rusts through — and the run-off stains concrete and stone for the first year. We stock it in 1.5–6 mm as laser-quality sheet and cut façade patterns, letters and panel blanks on our fibre lasers; 1 mm and 8–10 mm to order.
Chemical composition
| Element | C | Si | Mn | P | S | Cr | Cu | Ni | N |
|---|---|---|---|---|---|---|---|---|---|
| max. % (ladle) | ≤ 0.12 | ≤ 0.75 | ≤ 1.00 | 0.06–0.15 | ≤ 0.035 | 0.30–1.25 | 0.25–0.55 | ≤ 0.65 | ≤ 0.009 |
The high phosphorus is intentional (patina quality) and is what separates the WP grades from S355J2W (P ≤ 0.035). Maximum thickness 12 mm by the standard.
Mechanical properties
| Property | Requirement | Typical value | Note |
|---|---|---|---|
| Yield strength ReH | ≥ 355 MPa | 380–430 MPa | ≤ 16 mm |
| Tensile strength Rm | 470–630 MPa | 500–560 MPa | |
| Elongation A | ≥ 22 % | 24–30 % | L0 = 5.65 √S0 |
| Charpy V | ≥ 27 J at −20 °C | > 60 J | J2 |
| Bendability | 1 × t (≤ 3 mm), 1.5 × t above | good | |
| Corrosion rate (C3 atmosphere, after patina) | — | 2–5 µm/year | plain steel: 20–40 µm/year |
Equivalent grades
| System | Grade | Note |
|---|---|---|
| EN 10025-5 | S355J2WP (1.8946) | the standard |
| Trade name | Corten A / COR-TEN A | US Steel / ArcelorMittal (Indaten) |
| ASTM | A242 Type 1 | plate, approx. |
| ASTM | A606 Type 4 | sheet and strip, approx. |
| JIS G3125 | SPA-H | |
| GB/T 4171 | Q355GNH | Chinese |
| Lower-P plate grade | S355J2W (Corten B) | for structures |
How the patina develops
| Time | Appearance | What is happening | Run-off staining |
|---|---|---|---|
| Delivery | blue-grey mill scale or grey blast | no patina; keep dry and oil-free | — |
| 1–4 weeks | bright orange, patchy | first porous rust forms | heavy — protect paving |
| 2–6 months | even orange-brown | Cu/Cr/P start densifying the inner layer | moderate |
| 6–18 months | deep brown, matt | stable adherent patina | light |
| 2–5 years | chocolate to purple-brown | corrosion rate drops to a few µm/year | negligible |
| Sheltered / never wet | stays orange, dusty | no stable patina without wet-dry cycles | ongoing |
Pre-weathering (accelerated with salt-free wet-dry cycling or a chloride-free activator) gives an even patina before installation; we can supply pre-weathered panels to order. Blasting the mill scale off (Sa 2) gives the most uniform result.
Thickness range and stock sizes
| Thickness | Widths × lengths | Availability |
|---|---|---|
| 1.0 mm | 1 250 × 2 500; coil | to order 2–3 weeks |
| 1.5–3.0 mm | 1 250 / 1 500 × 2 500 / 3 000; 1 500 × 6 000 | stock, laser quality |
| 4–6 mm | 1 500 × 3 000 / 6 000 | stock |
| 8–10 mm | 1 500 / 2 000 × 6 000 | to order 2–3 weeks |
| Cut panels | laser per DXF, folded edges and fixing holes | from 200 m² |
Weight per m² and per sheet
| Thickness | kg/m² | 1 000 × 2 000 (kg) | 1 250 × 2 500 (kg) | 1 500 × 3 000 (kg) |
|---|---|---|---|---|
| 1 mm | 7.85 | 15.7 | 24.5 | 35.3 |
| 1.5 mm | 11.78 | 23.6 | 36.8 | 53.0 |
| 2 mm | 15.70 | 31.4 | 49.1 | 70.7 |
| 2.5 mm | 19.63 | 39.3 | 61.3 | 88.3 |
| 3 mm | 23.55 | 47.1 | 73.6 | 106.0 |
| 4 mm | 31.40 | 62.8 | 98.1 | 141.3 |
| 5 mm | 39.25 | 78.5 | 122.7 | 176.6 |
| 6 mm | 47.10 | 94.2 | 147.2 | 212.0 |
| 8 mm | 62.80 | 125.6 | 196.3 | 282.6 |
| 10 mm | 78.50 | 157.0 | 245.3 | 353.3 |
Nominal weights including coating where stated; a coil weighs kg/m² × width × strip length. Thickness tolerances to EN 10143 (coated) / EN 10131 (cold-rolled) / EN 10051 (hot-rolled).
Cutting, folding, welding and detailing
Laser and plasma cut cleanly (nitrogen-assist laser leaves an edge that weathers evenly); fold at 1–1.5 × t; form planters, cassettes and returns on the press brake. Weld with matching weathering consumables (ER80S-G / E8018-W2 type, or 2.5 % Ni wire) on visible joints so the seam patinates with the sheet — plain consumables leave a differently coloured, faster-rusting line; keep heat input moderate, no preheat under 10 mm. Design for drainage: no water traps, open bottoms on planters, a 10–20 mm gap to the ground, drip edges over paving, and stainless (A4) or weathering-steel fixings — galvanized fixings corrode sacrificially and streak. Separate from concrete and natural stone during the first year or accept the staining.
Where it is used
- Façade cladding, rain-screen cassettes and perforated screens
- Garden edging, retaining walls, planters and water features
- Sculptures, monuments, signage and lettering
- Fire bowls, barbecues and outdoor furniture
- Fencing, gates, gabion faces and privacy screens
- Interior feature walls and counters (sealed)
S355J2WP vs S355J2W vs S355J0WP
S355J0WP is the same steel with impact tested at 0 °C — interchangeable for architectural sheet and sometimes cheaper. S355J2W (Corten B) has normal phosphorus, is made in plate to 100 mm and is the grade for bridges, structures and containers; its patina is slightly less rich but its welds are easier. For a rust look without rust, painted or PPGI 'corten-effect' sheet exists, but it does not age.
Price
S355J2WP sheet is priced per ton from the weathering-steel list — well above plain S355 because of the alloy and the small mill runs; the bands below are the month\'s indicative FOB Istanbul ranges for stock sheet and for heavier sheet to order. Laser cutting and folding are quoted per panel.
Bands from our weekly export list (September 2026), FOB Istanbul, full-container quantities, excluding freight and certificates. Firm price per project on RFQ within one working day.
Export and packing
Packing of S355J2WP corten sheet: coils on cradles (eye-to-sky, VCI wrap, four straps, 5–25 t) or sheet packs on skids up to 3 t with interleaving paper and corner protectors; 20' ≈ one coil (≤ 20 t), 40' HC ≈ two coils or 24 t of sheet. Tariff 7210 / 7209 / 7208.
| Term | Detail |
|---|---|
| MOQ | 1 t (cut panels from 200 m²) |
| Incoterms | FOB Istanbul · CIF / CFR Gulf, Africa · DAP EU, Balkans, Iraq, Caucasus · DAP Aktau |
| Lead time | Stock 1.5–6 mm: 3–5 working days; 8–10 mm and coil 2–3 weeks |
| Packing | Sheets on skids ≤ 2 t, dry, no oil (patina must start clean); cut panels interleaved and crated |
| Container / truck | 20' ≈ 18–20 t; 40' HC ≈ 24 t of sheet |
| Documents | Invoice, packing list, EN 10204 3.1 (3.2 on request), certificate of origin; SASO / SONCAP / PVoC on request |
| Payment | 30% advance, balance against B/L copy; L/C at sight for orders above 100 t |
Certificates and testing
S355J2WP corten sheet is delivered with the mill certificate EN 10204 3.1 — heat number, ladle analysis, tensile and impact results and the delivery condition. Third-party 3.2 certification (Lloyd's, BV, TÜV, SGS), ultrasonic testing to EN 10160 and extra Charpy tests at a lower temperature are ordered per lot.
How to order
Specify S355J2WP (or J0WP), thickness × width × length or the DXF for cut panels, quantity in sheets, tons or m², surface (mill scale / blasted / pre-weathered), folding details and delivery; state exposure (inland, coastal, sheltered) — we advise whether weathering steel will patinate there.
Standards
- EN 10025-5 — S355J2WP (1.8946), S355J0WP (1.8945)
- ASTM A242 Type 1 (approx.), ASTM A606 Type 4 (sheet)
- EN 10051 / EN 10029 tolerances
- EN 10204 3.1
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: S355J2WP · S355J0WP · S355J2W
Frequently asked questions
What is S355J2WP?
The European weathering steel grade (EN 10025-5, material 1.8946) alloyed with copper, chromium and extra phosphorus — the equivalent of Corten A — in sheet up to 12 mm, forming a protective rust patina instead of scaling.
Is S355J2WP the same as Corten A?
It is the EN equivalent: same phosphorus-alloyed chemistry and patina behaviour. Corten is a trade name; ASTM A242 / A606 are the US specifications.
How long does corten take to rust?
Bright orange in weeks, an even brown patina in 6–18 months, dark and stable in 2–5 years — provided the surface wets and dries in cycles.
Does corten steel rust through?
Not in normal outdoor exposure — after the patina forms, loss is 2–5 µm a year. It does rust through where it stays wet, is buried, or sits in salt spray.
What thickness of corten for a façade or planter?
Façade cassettes 1.5–3 mm, screens and edging 3–4 mm, planters 3–6 mm, retaining walls and sculptures 6–10 mm; allow ≈ 0.5 mm total loss over the design life.
Can S355J2WP be welded?
Yes — with weathering-grade consumables on visible seams so the weld patinates with the sheet; the high phosphorus calls for moderate heat input and it is limited to 12 mm.
What is the price of corten sheet?
Per ton FOB Istanbul — see the band above; cut and folded panels are quoted per piece or per m².