Steel S420N
EN S420N · GB Q420C
S420N (1.8902, comparable to Q420C) is a normalized fine-grain structural steel offered in N conditions by thickness up to 200 mm, in low-temperature NL and as N+A.
Reference datasheet — S420N 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
S420N tempers and conditions
S420N is supplied in 7 conditions, soft to hard. N is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
N | Very heavy plate; strength band drops to 500–650 MPa Rm and 340/330 MPa minimum yield. | 370 | 540 | 21 | 158 HB | 8.6 % IACS |
N | Thick plate for heavy welded structures; yield 370–360 MPa minimum, preheat recommended for welding. | 395 | 550 | 21 | 162 HB | 8.6 % IACS |
N | Heavy plate: 390 MPa minimum yield; check through-thickness toughness for welded joints. | 415 | 555 | 22 | 165 HB | 8.6 % IACS |
N + stress-relief annealed | For welded fabrications requiring PWHT at 530–580 °C; slight loss of yield strength, improved dimensional stability. | 420 | 550 | 24 | 163 HB | 8.6 % IACS |
N | Medium plate thickness: yield derated to 400 MPa minimum per EN 10025-3. | 425 | 560 | 22 | 168 HB | 8.6 % IACS |
NDefault Normalized | Standard delivery condition for plate, section and bar up to 16 mm; full 420 MPa yield with 40 J at -20 °C. | 440 | 570 | 23 | 170 HB | 8.6 % IACS |
Normalized, low-temperature impact quality | Choose when guaranteed 27 J Charpy at -50 °C and tighter P/S limits are required (offshore, cryogenic-adjacent, Arctic structures). | 445 | 575 | 24 | 170 HB | 8.6 % IACS |
What is S420N?
S420N (1.8902, comparable to Q420C) is a normalized fine-grain structural steel offered in N conditions by thickness up to 200 mm, in low-temperature NL and as N+A. It fills the gap where S355 is not strong enough but quenched-and-tempered plate is not required; typical values are 440 MPa yield, 570 MPa tensile, 23 % elongation and 170 HB. CEV up to 0.50 keeps it weldable with low-hydrogen consumables and 100–150 °C preheat above about 30 mm, but it has no corrosion resistance and always needs coating. S460N is the next strength step, while E420M gives similar strength with a lower CEV. S420N has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). S420N has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 50% of steel grades. Elongation at break is 23% and the elastic modulus is 210 GPa (30.5 Msi).
What is S420N used for?
- structural steelwork
- pressure equipment
- cranes
- mobile equipment frames
Advantages
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S420N properties
Typical room-temperature values for S420N-N; bars are the position among steel grades.
Physical3
S420N has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
S420N has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 50% of steel grades. Elongation at break is 23% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S420N is rated for continuous service to 350°C (662 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
S420N conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of S420N takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
S420N's machinability is good (55/100, better than 62% of steel grades); weldability very good (80/100); formability good (60/100).
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. S420N is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S420N
Is S420N easy to machine?
Machines like a normalized C-Mn steel at ~55–60 % of 1212; use rigid setups, coated carbide and moderate feeds — sticky chips and mild work-hardening at low feed rates.
Can S420N be welded?
Good weldability with CEV ≤ 0.50; use low-hydrogen consumables, control heat input to 1.0–2.5 kJ/mm and preheat 100–150 °C above ~30 mm to protect HAZ toughness.
Can S420N be formed, bent or molded?
Cold formable with generous radii (≈2t transverse, 1.5t longitudinal for thin plate); hot forming above 900 °C requires re-normalizing to restore the fine-grain properties.
S420N 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 for t ≤ 63 mm | ≤ 0.2 | 0.16 |
| Si | ≤ 0.6 | 0.35 |
| Mn | 1 – 1.7 | 1.45 |
| P0.025 max for S420NL | ≤ 0.03 | 0.02 |
| S0.020 max for S420NL | ≤ 0.03 | 0.01 |
| N0.020 for NL; limit may be exceeded if sufficient N-binding elements present | ≤ 0.03 | 0.01 |
| Altotal Al; alternative N-binding elements permitted | ≥ 0.02 | 0.04 |
| NbNb+Ti+V total ≤ 0.22 | ≤ 0.05 | 0.03 |
| V | ≤ 0.2 | 0.08 |
| Ti | ≤ 0.05 | 0.02 |
| Cr | ≤ 0.3 | 0.08 |
| Ni | ≤ 0.8 | 0.15 |
| Mo | ≤ 0.1 | 0.03 |
| Cu | ≤ 0.7 | 0.15 |
| Zr | ≤ 0.15 | |
| FeCEV ≤ 0.50 for t ≤ 63 mm per EN 10025-3 | balance |
What surface finishes work on S420N?
No inherent corrosion resistance — blast to Sa 2½ then paint, metallize or hot-dip galvanize; keep Si low if bright galvanized appearance is required.
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 S420N in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.8902
- GB (China)
- Q420C
How much does S420N cost?
S420N 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.
S420N — frequently asked
What is S420N used for?
S420N is typically used for structural steelwork, pressure equipment, cranes and mobile equipment frames. In short: between S355 and S460; normalized, no QT needed; good weldability at 420 MPa.
What is the yield strength of S420N?
S420N has a typical yield strength of 440 MPa (63.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 50% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is S420N easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a normalized C-Mn steel at ~55–60 % of 1212; use rigid setups, coated carbide and moderate feeds — sticky chips and mild work-hardening at low feed rates.
Can S420N be welded?
Yes — weldability is rated very good (80/100). Good weldability with CEV ≤ 0.50; use low-hydrogen consumables, control heat input to 1.0–2.5 kJ/mm and preheat 100–150 °C above ~30 mm to protect HAZ toughness.
What surface finishes work on S420N?
No inherent corrosion resistance — blast to Sa 2½ then paint, metallize or hot-dip galvanize; keep Si low if bright galvanized appearance is required.
Can S420N be formed, bent or molded?
Cold formable with generous radii (≈2t transverse, 1.5t longitudinal for thin plate); hot forming above 900 °C requires re-normalizing to restore the fine-grain properties.
What is the maximum service temperature of S420N?
S420N 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.
What is the difference between S420N-N and S420N-NL?
N is the default condition — standard delivery condition for plate, section and bar up to 16 mm; full 420 MPa yield with 40 J at -20 °C. NL: choose when guaranteed 27 J Charpy at -50 °C and tighter P/S limits are required (offshore, cryogenic-adjacent, Arctic structures). Yield strength is 440 MPa in N versus 445 MPa in NL.
How much does S420N cost?
S420N 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 — Part 3: Normalized/normalized rolled weldable fine grain structural steels — CEN (2019)
- GB/T 1591 High strength low alloy structural steels (Q420C/D) — SAC (2018)
- EN 1011-2 Welding — Recommendations for welding of metallic materials: arc welding of ferritic steels — CEN (2001)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Fine-grain structural steel plate datasheets (S420N/S420NL) — European plate mills (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.