Steel S420M
EN S420M
S420M is a thermomechanically rolled fine-grain structural steel to EN 10025-4 (1.8825), supplied at 460 MPa yield, 570 MPa tensile, 24 % elongation and 170 HB in the default M condition.
Reference datasheet — S420M 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 M condition
S420M tempers and conditions
S420M is supplied in 6 conditions, soft to hard. M is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M | Heavy plate class for thick welded sections; lowest strength class of the grade. | 420 | 540 | 23 | 160 HB | 8 % IACS |
ML | Heavy arctic/offshore plate; combine with low-hydrogen consumables and controlled heat input. | 420 | 540 | 23 | 160 HB | 8 % IACS |
M | Medium plate thickness class; standard yield drops to 400 MPa minimum. | 440 | 550 | 24 | 165 HB | 8 % IACS |
ML | Thicker arctic-grade plate; yield minimum 400 MPa with -50 °C impact guarantee. | 440 | 550 | 24 | 165 HB | 8 % IACS |
MDefault Thermomechanically controlled processed | Standard stocked condition for general welded structures down to -20 °C service. | 460 | 570 | 24 | 170 HB | — |
Thermomechanically rolled, low-temperature quality (27 J at -50 °C), t… | Choose for arctic, offshore or cryo-adjacent structures needing guaranteed toughness at -50 °C. | 460 | 570 | 25 | 170 HB | 8 % IACS |
What is S420M?
S420M is a thermomechanically rolled fine-grain structural steel to EN 10025-4 (1.8825), supplied at 460 MPa yield, 570 MPa tensile, 24 % elongation and 170 HB in the default M condition. It is used where higher strength allows lighter welded sections, and is stocked as plate in thickness bands to 63 mm with ML variants for low-temperature toughness. Weldability stays good with CEV ≤ 0.46, but formability is lower than S275ML and hot forming or normalizing above about 580 °C removes the TMCP strengthening. Choose S275ML when heavier cold forming is needed. S420M has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). S420M has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 55% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
What is S420M used for?
- heavy structural steel
- cranes
- mobile equipment frames
Advantages
- Readily welded — 88/100, better than 87% 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
S420M properties
Typical room-temperature values for S420M-M; bars are the position among steel grades.
Physical3
S420M has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
S420M has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 55% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S420M 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
S420M conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S420M takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 25%.
Manufacturability7
S420M's machinability is good (55/100, better than 62% of steel grades); weldability excellent (88/100); 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. S420M is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S420M
Is S420M easy to machine?
Machines like a tough HSLA plate — use rigid setups, positive-rake carbide, moderate speeds and generous feed to avoid work-hardened, gummy surfaces.
Can S420M be welded?
Excellent weldability with CEV ≤0.46; use low-hydrogen consumables matching 420 MPa yield, control heat input (typically ≤3.5 kJ/mm) and avoid excessive interpass temperature so the TMCP fine grain and HAZ toughness are preserved.
Can S420M be formed, bent or molded?
Cold-forms and press-brakes well with bend radii of about 2t–3t transverse to rolling; hot forming or normalizing above ~580 °C degrades TMCP strength, and stress relief should stay in the 530–580 °C band.
S420M 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 |
|---|---|---|
| CEN 10025-4 max for S420M/ML | ≤ 0.16 | 0.1 |
| Si | ≤ 0.5 | 0.3 |
| Mn | 0.8 – 1.7 | 1.5 |
| PML quality ≤0.025 | ≤ 0.03 | 0.02 |
| SML quality ≤0.020 | ≤ 0.03 | 0.01 |
| Altotal Al, or other grain-refining elements | ≥ 0.02 | 0.04 |
| Nbmicroalloy; Nb+V+Ti ≤0.22 | ≤ 0.05 | 0.03 |
| V | ≤ 0.12 | 0.05 |
| Ti | ≤ 0.05 | 0.02 |
| Cr | ≤ 0.3 | 0.1 |
| Nihigher Ni typical in ML for low-T toughness | ≤ 0.8 | 0.2 |
| Mo | ≤ 0.2 | 0.05 |
| Cu | ≤ 0.55 | 0.15 |
| N | ≤ 0.03 | 0.01 |
| Zr | ≤ 0.15 | |
| FeCEV (IIW) ≤ 0.46 for t ≤ 63 mm | balance |
What surface finishes work on S420M?
Not anodizable; protect by blasting to Sa 2½ plus epoxy/zinc-rich paint, thermal-spray zinc or hot-dip galvanizing (watch Si content for coating appearance).
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 S420M in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.882510025-4
How much does S420M cost?
S420M 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.
S420M — frequently asked
What is S420M used for?
S420M is typically used for heavy structural steel, cranes and mobile equipment frames. In short: higher strength than S275ML; lighter welded structures; low CEV, ≤ 0.46.
What is the yield strength of S420M?
S420M has a typical yield strength of 460 MPa (66.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 55% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S420M easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a tough HSLA plate — use rigid setups, positive-rake carbide, moderate speeds and generous feed to avoid work-hardened, gummy surfaces.
Can S420M be welded?
Yes — weldability is rated excellent (88/100). Excellent weldability with CEV ≤0.46; use low-hydrogen consumables matching 420 MPa yield, control heat input (typically ≤3.5 kJ/mm) and avoid excessive interpass temperature so the TMCP fine grain and HAZ toughness are preserved.
What surface finishes work on S420M?
Not anodizable; protect by blasting to Sa 2½ plus epoxy/zinc-rich paint, thermal-spray zinc or hot-dip galvanizing (watch Si content for coating appearance).
Can S420M be formed, bent or molded?
Cold-forms and press-brakes well with bend radii of about 2t–3t transverse to rolling; hot forming or normalizing above ~580 °C degrades TMCP strength, and stress relief should stay in the 530–580 °C band.
What is the maximum service temperature of S420M?
S420M 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 S420M-M and S420M M-40-63?
M is the default condition — standard stocked condition for general welded structures down to -20 °C service. M-40-63: heavy plate class for thick welded sections; lowest strength class of the grade. Yield strength is 460 MPa in M versus 420 MPa in M-40-63.
How much does S420M cost?
S420M 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 10025-4 Hot rolled products of structural steels — Part 4: Thermomechanical rolled weldable fine grain structural steels — CEN (2019)
- EN 10027-2 / Stahl-Eisen-Liste material number 1.8825 — CEN / VDEh (2015)
- 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)
- Thermomechanically rolled fine-grain structural steel plate datasheets (S420M/ML) — Dillinger / SSAB / voestalpine (2023)
- GB/T 1591 (Q420 comparison) — SAC (2018)
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.