Steel S420NL +N 200-250 (+N)
Heat-treated state
EN S420NL
Maximum standard thickness class, 300 MPa minimum yield; only from heavy-plate mills by agreement.
Values for the +N 200-250 condition
Other S420NL tempers and conditions
S420NL is listed in 9 conditions; see the grade overview at S420NL.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+N 200-250This page +N | Maximum standard thickness class, 300 MPa minimum yield; only from heavy-plate mills by agreement. | 330 | 510 | 20 | 152 HB | 8.2 % IACS |
+N | Mill-order-only extra-heavy plate, 320 MPa minimum yield; requires agreed impact sampling position. | 350 | 520 | 21 | 155 HB | 8.2 % IACS |
+N | Special heavy-plate order; 340 MPa minimum yield, toughness testing usually at mid-thickness. | 370 | 530 | 22 | 158 HB | 8.2 % IACS |
+N | Very heavy plate, 360 MPa minimum yield; used for machine bases and offshore nodes. | 390 | 540 | 22 | 162 HB | 8.2 % IACS |
+N | Thick plate condition, 370 MPa minimum yield; check through-thickness quality for heavy welds. | 400 | 555 | 23 | 165 HB | 8.2 % IACS |
+N | Heavy plate for welded frames; 390 MPa minimum yield, slightly lower tensile band. | 420 | 560 | 23 | 168 HB | 8.2 % IACS |
+N | Medium plate thickness; yield drops to 400 MPa minimum while tensile band is unchanged. | 430 | 575 | 24 | 172 HB | 8.2 % IACS |
+N + stress relieved | Choose when heavy welding or cold forming demands dimensional stability and reduced residual stress; small strength loss, toughness retained. | 430 | 565 | 25 | 170 HB | 8.2 % IACS |
+NDefault Normalized | Standard stocked delivery condition for plate and sections up to 16 mm; full 420 MPa minimum yield with -50 °C toughness. | 450 | 580 | 24 | 175 HB | 8.2 % IACS |
What is S420NL +N 200-250?
S420NL +N 200-250 is S420NL heat treated to +N 200-250 — maximum standard thickness class, 300 MPa minimum yield; only from heavy-plate mills by agreement. S420NL +N 200-250 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 78% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi). S420NL +N 200-250 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F). +N is the default condition FabDigit quotes; +N 200-250 is available on request or by drawing note.
Advantages
- Readily welded — 76/100, better than 77% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
- Low strength — 330 MPa (47.9 ksi), worse than 78% of steel grades
S420NL +N 200-250 properties
Typical room-temperature values for S420NL +N 200-250; 22 are specific to this condition. Other listed values are S420NL reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S420NL +N 200-250 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical16
S420NL +N 200-250 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 78% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S420NL +N 200-250 is rated for continuous service to 350°C (662 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
S420NL +N 200-250 conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S420NL +N 200-250 takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
S420NL +N 200-250's machinability is good (58/100, better than 75% of steel grades); weldability very good (76/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S420NL +N 200-250
Is S420NL easy to machine?
Machines like a tough 1.4–1.7 % Mn microalloyed plate: use rigid setups, coated carbide, moderate speeds and positive rake; the ductile normalized structure tends to build up burrs rather than chip freely.
Can S420NL be welded?
Excellent weldability by SMAW/GMAW/SAW/FCAW with low-hydrogen consumables matching 420 MPa yield; keep CEV-based preheat (typ. 100–150 °C for thick sections), control heat input to avoid HAZ grain coarsening and preserve -50 °C toughness.
Can S420NL be formed, bent or molded?
Cold bends readily at generous radii (typ. ≥2.5–3×t transverse to rolling); hot forming should be finished above ~850 °C and followed by re-normalizing to restore the fine-grain toughness.
What surface finishes work on S420NL?
No anodizing; shot blast to SA 2.5 then epoxy/zinc-rich primer, thermal spray or hot-dip galvanize (watch Si level for coating appearance) — bare steel corrodes quickly outdoors.
S420NL chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cmax per EN 10025-3 | ≤ 0.2 | 0.16 |
| Si | ≤ 0.6 | 0.35 |
| Mn | 1 – 1.7 | 1.45 |
| PNL quality | ≤ 0.03 | 0.02 |
| SNL quality | ≤ 0.02 | 0.01 |
| N | ≤ 0.03 | 0.01 |
| Altotal Al, grain refinement | ≥ 0.02 | 0.04 |
| NbNb+Ti+V ≤ 0.22 total | ≤ 0.05 | 0.03 |
| V | ≤ 0.2 | 0.08 |
| Ti | ≤ 0.05 | 0.02 |
| Cr | ≤ 0.3 | 0.1 |
| Ni | ≤ 0.8 | 0.2 |
| Mo | ≤ 0.1 | 0.03 |
| Cu | ≤ 0.7 | 0.15 |
| Zr | ≤ 0.15 | — |
| FeCEV (IIW) ≤ 0.50 for t ≤ 63 mm | balance | — |
S420NL +N 200-250 — frequently asked
What is S420NL +N 200-250 used for?
S420NL +N 200-250 is typically used for offshore and marine structures, heavy welded fabrications and cold-climate steel structures. In short: tougher than S355; -50 °C impact certified; very good weldability.
What is the yield strength of S420NL +N 200-250?
S420NL +N 200-250 has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 78% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is S420NL +N 200-250 easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a tough 1.4–1.7 % Mn microalloyed plate: use rigid setups, coated carbide, moderate speeds and positive rake; the ductile normalized structure tends to build up burrs rather than chip freely.
Can S420NL +N 200-250 be welded?
Yes — weldability is rated very good (76/100). Excellent weldability by SMAW/GMAW/SAW/FCAW with low-hydrogen consumables matching 420 MPa yield; keep CEV-based preheat (typ. 100–150 °C for thick sections), control heat input to avoid HAZ grain coarsening and preserve -50 °C toughness.
What surface finishes work on S420NL +N 200-250?
No anodizing; shot blast to SA 2.5 then epoxy/zinc-rich primer, thermal spray or hot-dip galvanize (watch Si level for coating appearance) — bare steel corrodes quickly outdoors.
Can S420NL +N 200-250 be formed, bent or molded?
Cold bends readily at generous radii (typ. ≥2.5–3×t transverse to rolling); hot forming should be finished above ~850 °C and followed by re-normalizing to restore the fine-grain toughness.
What is the maximum service temperature of S420NL +N 200-250?
S420NL +N 200-250 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10025-3: Hot rolled products of structural steels — Technical delivery conditions for normalized/normalized rolled weldable fine grain structural steels — CEN (2019)
- EN 10164: Steel products with improved deformation properties perpendicular to the surface — CEN (2018)
- EN 1011-2: Welding — Recommendations for welding of metallic materials, Part 2: Arc welding of ferritic steels — CEN (2001)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Normalized fine-grain structural steel plate datasheets (S420N/S420NL) — European heavy-plate producers (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.