Steel S420NL
EN S420NL
S420NL (1.8912, WStE420) is a normalized fine-grain weldable structural steel with certified -50 °C impact toughness, one strength step below S460NL.
Reference datasheet — S420NL is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +N condition
S420NL tempers and conditions
S420NL is supplied in 9 conditions, soft to hard. +N is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+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 |
Supply forms, finishes and certifications
Ways S420NL is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
+N +Z35 | +N with Z35 through-thickness quality | Certification |
What is S420NL?
S420NL (1.8912, WStE420) is a normalized fine-grain weldable structural steel with certified -50 °C impact toughness, one strength step below S460NL. It is chosen for heavy welded structures in cold service and is stocked as plate and sections in +N from thin gauge up to 250 mm, plus +N+SR and +Z35 through-thickness qualities. Default +N values are 450 MPa yield, 580 MPa tensile, 24 % elongation and 175 HB, with weldability rated 85 and machinability about 55 % of AISI 1212. Bare steel has no corrosion resistance, and hot-formed parts must be re-normalized. S420NL 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). S420NL has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 580 MPa (84.1 ksi) — stronger than 52% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
What is S420NL used for?
- offshore and marine structures
- heavy welded fabrications
- cold-climate steel structures
Advantages
- Readily welded — 85/100, better than 83% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S420NL properties
Typical room-temperature values for S420NL-+N; bars are the position among steel grades.
Physical3
S420NL 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 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 580 MPa (84.1 ksi) — stronger than 52% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S420NL 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 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 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's machinability is good (55/100, better than 62% of steel grades); weldability excellent (85/100); formability good (65/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. S420NL is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S420NL
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel S420NL in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.8912
- Similar grades
- WStE420
How much does S420NL cost?
S420NL is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S420NL — frequently asked
What is S420NL used for?
S420NL 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?
S420NL has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 580 MPa (84.1 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is S420NL easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% 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 be welded?
Yes — weldability is rated excellent (85/100). 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?
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 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?
S420NL 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.
How much does S420NL cost?
S420NL is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.