What is S355J2+N steel plate?
The +N in S355J2+N is a delivery condition, not a different steel: the plate is normalised (heated to about 900 °C and air-cooled) or normalised-rolled (finished at a controlled temperature that produces the same microstructure), giving a fine, uniform grain and properties that no longer depend on where in the plate you cut the test piece. The S355J2 base — 355 MPa yield, 27 J at −20 °C, P and S ≤ 0.025 %, fully killed — is unchanged. Why pay for it: as-rolled (+AR) thick plate cools unevenly, so its core can be coarser and less tough than the certificate suggests, and it carries rolling stresses that release as distortion when you weld or flame-cut it. Normalised plate is stable, machines and bends predictably, and passes ultrasonic inspection more reliably. EN 10025-2 lets the mill choose +AR or +N unless the buyer specifies; for anything above 40 mm, for bridge, crane and wind-tower specifications, and for plate that will be heavily flame-cut or machined, the buyer should specify +N.
Chemical composition
| Element | C | Si | Mn | P | S | Cu |
|---|---|---|---|---|---|---|
| max. % (ladle) | 0.20 (≤ 30 mm) / 0.22 | 0.55 | 1.60 | 0.025 | 0.025 | 0.55 |
Fully killed. Mills producing +N typically keep C ≤ 0.18 and add Nb/V micro-alloying for grain refinement. CEV 0.45–0.49 by thickness.
Mechanical properties
| Thickness | Yield ReH min (MPa) | Tensile Rm (MPa) | Elongation A min | Impact KV (long.) |
|---|---|---|---|---|
| ≤ 16 mm | 355 | 470–630 | 22 % | 27 J at −20 °C |
| > 16–40 mm | 345 | 470–630 | 22 % | 27 J at −20 °C |
| > 40–63 mm | 335 | 470–630 | 21 % | 27 J at −20 °C |
| > 63–80 mm | 325 | 470–630 | 20 % | 27 J at −20 °C |
| > 80–100 mm | 315 | 470–630 | 20 % | 27 J at −20 °C |
| > 100–150 mm | 295 | 450–600 | 18 % | 27 J at −20 °C |
Equivalent grades
| System | Grade | Note |
|---|---|---|
| DIN 17100 | ST52-3 N | direct predecessor |
| EN 10025-3 | S355N / S355NL | fine-grain normalised, NL −50 °C |
| ASTM | A572 Gr. 50 normalised / A709 Gr. 50 | |
| JIS G3106 | SM490C (N) | |
| GB/T 1591 | Q355D (N) | |
| BS 4360 | 50D normalised | historic |
Thickness range and stock sizes
| Thickness | Widths × lengths | Availability |
|---|---|---|
| 8–20 mm | 2 000 / 2 500 × 6 000–12 000 | to order 3–4 weeks |
| 25–60 mm | 2 000 / 2 500 / 3 000 × 6 000–12 000 | to order 3–5 weeks |
| 80–150 mm | 2 000–2 500 × 4 000–8 000 | to order 4–6 weeks, UT S1/E1 standard |
Weight per m² and per plate
| Thickness | kg/m² | 1 500 × 6 000 (kg) | 2 000 × 6 000 (kg) | 2 500 × 12 000 (kg) |
|---|---|---|---|---|
| 8 mm | 62.8 | 565 | 754 | 1 884 |
| 10 mm | 78.5 | 707 | 942 | 2 355 |
| 12 mm | 94.2 | 848 | 1 130 | 2 826 |
| 15 mm | 117.8 | 1 060 | 1 413 | 3 533 |
| 20 mm | 157.0 | 1 413 | 1 884 | 4 710 |
| 25 mm | 196.3 | 1 766 | 2 355 | 5 888 |
| 30 mm | 235.5 | 2 120 | 2 826 | 7 065 |
| 40 mm | 314.0 | 2 826 | 3 768 | 9 420 |
| 50 mm | 392.5 | 3 533 | 4 710 | 11 775 |
| 60 mm | 471.0 | 4 239 | 5 652 | 14 130 |
| 80 mm | 628.0 | 5 652 | 7 536 | 18 840 |
| 100 mm | 785.0 | 7 065 | 9 420 | 23 550 |
| 120 mm | 942.0 | 8 478 | 11 304 | 28 260 |
| 150 mm | 1,177.5 | 10 598 | 14 130 | 35 325 |
Weights are theoretical. EN 10029 class A allows up to +4 % on thin plate, and unless the contract says otherwise the invoice follows the theoretical figure, not the weighbridge.
Welding, cutting and forming
Normalised plate welds like S355J2 but with fewer surprises: preheat 75–100 °C above 25 mm (100–125 °C above 60 mm), basic low-hydrogen consumables, heat input 1.0–2.5 kJ/mm, interpass ≤ 250 °C. Do not exceed 3.5 kJ/mm on thick +N plate — high heat input coarsens the grain the normalising paid for. Post-weld heat treatment (580–620 °C) is optional for stress relief on machine beds and is compatible with the grade. Cold forming to 2 × t; hot forming above 900 °C requires re-normalising. Flame-cut edges are softer and more uniform than on +AR plate; machining is free-cutting with the fine grain.
Where it is used
- Bridge girders and orthotropic decks (EN 1090 EXC3/EXC4)
- Crane runway girders, gantry and portal cranes
- Wind-turbine towers, transition pieces and flanges
- Machine beds, press frames and rolling-mill housings
- Heavy foundations, anchor and base plates ≥ 40 mm
- Non-pressure heavy vessels, hoppers and chutes
S355J2+N vs S355J2+AR
Same grade, different delivery: +AR is cheaper, faster and fine below about 30 mm; +N costs 10–20 USD/t more and takes the mill programme, but gives guaranteed through-thickness toughness, ultrasonic soundness and dimensional stability in heavy plate. If the plate is over 40 mm, will be welded heavily, flame-cut into large parts or machined flat, order +N. See S355J2 for the as-rolled stock item and S355K2 for the 40 J version.
Price
+N plate is priced on the heavy-plate list with the J2+N premium (about 90 USD/t over S235JR). Ultrasonic testing, Z-quality and 3.2 inspection are added per ton. The band below is the month's indicative FOB Istanbul range for made-to-order plate.
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
How S355J2+N steel plate leaves Dilovası: loose on timber bearers, strapped in bundles ≤ 10 t. Loading: ≤ 6 m: 40' HC 24–25 t; 8–12 m: flat-rack or breakbulk Derince. The HS heading depends on the product: 7208 / 7209 / 7210 for carbon strip, 7225 / 7226 where alloyed.
| Term | Detail |
|---|---|
| MOQ | 10 t of one thickness |
| Incoterms | FOB Istanbul · CIF / CFR Gulf, Africa · DAP EU, Balkans, Iraq, Caucasus · DAP Aktau |
| Lead time | To order 3–6 weeks (mill programme); 8–30 mm sometimes ex EU stock 2 weeks |
| Packing | Loose on timber bearers, strapped in bundles ≤ 10 t |
| Container / truck | ≤ 6 m: 40' HC 24–25 t; 8–12 m: flat-rack or breakbulk Derince |
| 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
Every lot of S355J2+N steel plate carries an EN 10204 3.1 inspection certificate listing heat, chemistry, mechanical and impact results. Where the client's QA requires it we book 3.2 inspection before rolling rather than after. We can add EN 10160 ultrasonic examination and Charpy sets at the temperature you nominate.
How to order
Specify thickness × width × length, tonnage, UT class (EN 10160 S1/E1 is our default above 40 mm), Z-quality if any, certificate 3.1 or 3.2, and the required delivery date; we confirm the mill slot within one working day.
Standards
- EN 10025-2:2019 — S355J2+N (1.0577)
- EN 10160 — ultrasonic testing classes S1–S3 / E1–E4
- EN 10164 — Z15 / Z25 / Z35 through-thickness
- EN 10029 class A/B/C
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: S355J2 · S355K2 · S355N
Frequently asked questions
What does +N mean in S355J2+N?
Normalised or normalised-rolled delivery condition: the plate has a fine, uniform grain and guaranteed properties through the full thickness, unlike as-rolled (+AR) plate.
Is S355J2+N the same as ST52-3 N?
Yes — ST52-3 N (DIN 17100) was the normalised, fully-killed −20 °C grade; S355J2+N is its EN 10025-2 successor.
When must I specify +N instead of +AR?
Above about 40 mm, for bridges, cranes and wind towers, for plate that will be heavily welded, flame-cut or machined, and whenever the specification calls for through-thickness toughness or ultrasonic testing.
What is the difference between S355J2+N and S355N?
S355N (EN 10025-3) is a micro-alloyed fine-grain steel normalised by definition, with slightly different chemistry limits and higher impact energy at −20 °C (40 J long.); S355J2+N is the EN 10025-2 grade delivered normalised. They are interchangeable in most structural uses; S355N is stricter.
What is the lead time for S355J2+N plate from Turkey?
3–6 weeks from the mill programme depending on thickness; 8–30 mm is occasionally available ex EU stock in 2 weeks.