Steel S420ML
EN S420ML
S420ML (1.8836) is a thermomechanically rolled fine-grain structural steel to EN 10025-4 with guaranteed low-temperature Charpy toughness, one strength step above S355ML at 465 MPa yield, 585 MPa tensile, 24 % elongation and 178 HB.
Reference datasheet — S420ML 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 TM condition
S420ML tempers and conditions
S420ML is supplied in 4 conditions, soft to hard. TM is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
TM | Thickest supply range (mill-dependent, often only to 100–120 mm); lowest strength class of the grade. | 400 | 545 | 22 | 163 HB | 8.2 % IACS |
TM | Heavy plate class for main girders and thick weldments; slightly lower yield, may need modest preheat. | 420 | 560 | 23 | 168 HB | 8.2 % IACS |
TM | Medium plate thickness class; yield drops one step but −50 °C toughness is unchanged. | 440 | 570 | 24 | 172 HB | 8.2 % IACS |
TMDefault Thermomechanically rolled, thickness ≤ 16 mm | Standard as-delivered TM condition for thin plate and sections; highest guaranteed strength class of the grade. | 465 | 585 | 24 | 178 HB | 8.2 % IACS |
Supply forms, finishes and certifications
Ways S420ML is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
TM+Z | TM + Z-quality | Certification |
What is S420ML?
S420ML (1.8836) is a thermomechanically rolled fine-grain structural steel to EN 10025-4 with guaranteed low-temperature Charpy toughness, one strength step above S355ML at 465 MPa yield, 585 MPa tensile, 24 % elongation and 178 HB. It is used for welded steelwork in cold regions, with weldability rated 88 and plate available in TM conditions to 120 mm plus through-thickness (Z) quality. Formability is lower than S355ML (62 against 78) and machinability runs near 55 % of AISI 1212; hot forming above about 580 °C and post-weld normalizing are not allowed. S355ML is the more formable and more weldable alternative. S420ML has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F). S420ML has a yield strength of 465 MPa (67.4 ksi) and a tensile strength of 585 MPa (84.8 ksi) — stronger than 56% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
What is S420ML used for?
- offshore platforms
- arctic cranes
- structural steelwork in cold climates
Advantages
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Readily welded — 88/100, better than 87% of steel grades
- Forms and bends easily — 62/100, better than 78% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S420ML properties
Typical room-temperature values for S420ML-TM; bars are the position among steel grades.
Physical3
S420ML has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F).
Mechanical16
S420ML has a yield strength of 465 MPa (67.4 ksi) and a tensile strength of 585 MPa (84.8 ksi) — stronger than 56% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S420ML 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
S420ML conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of S420ML takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
S420ML's machinability is good (55/100, better than 62% of steel grades); weldability excellent (88/100); formability good (62/100).
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. S420ML is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S420ML
Is S420ML easy to machine?
Machines like a tough HSLA plate at roughly 55 % of 1212 — use rigid setups, positive-rake coated carbide and generous feed to break the stringy chips.
Can S420ML be welded?
Excellent weldability by SAW/GMAW/FCAW with low-hydrogen consumables; keep heat input moderate to protect the fine-grain TM structure, control interpass temperature and avoid post-weld normalizing.
Can S420ML be formed, bent or molded?
Cold-form and press-brake with bend radii per EN 10025-4 (≈2t transverse for thin plate); do not hot-form above about 580 °C or the TM strength is lost and re-normalizing is not permitted.
S420ML 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 | ≤ 1.7 | 1.45 |
| PML sub-grade limit | ≤ 0.03 | 0.01 |
| SML sub-grade limit | ≤ 0.02 | 0.01 |
| Altotal Al; other N-binding elements may substitute | ≥ 0.02 | 0.04 |
| Nbmicro-alloying | ≤ 0.05 | 0.03 |
| Vmicro-alloying | ≤ 0.12 | 0.05 |
| Timicro-alloying | ≤ 0.05 | 0.02 |
| Cr | ≤ 0.3 | 0.05 |
| Niaids low-temperature toughness | ≤ 0.8 | 0.15 |
| Mo | ≤ 0.2 | 0.03 |
| Cu | ≤ 0.55 | 0.1 |
| N | ≤ 0.03 | 0.01 |
| Zr | ≤ 0.15 | |
| CEVIIW carbon equivalent, t ≤ 63 mm (0.47 for thicker) | ≤ 0.45 | 0.4 |
| Fe | balance |
What surface finishes work on S420ML?
Bare steel — shot blast to Sa 2½ and apply zinc-rich primer, duplex paint or hot-dip galvanizing; check silicon content before galvanizing to avoid thick brittle coatings.
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 S420ML in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.883610025-4
How much does S420ML cost?
S420ML is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S420ML — frequently asked
What is S420ML used for?
S420ML is typically used for offshore platforms, arctic cranes and structural steelwork in cold climates. In short: higher-strength cold-service structural; 465 MPa yield, weldable; stronger S355ML upgrade.
What is the yield strength of S420ML?
S420ML has a typical yield strength of 465 MPa (67.4 ksi) and a tensile strength of 585 MPa (84.8 ksi) — stronger than 56% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is S420ML easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a tough HSLA plate at roughly 55 % of 1212 — use rigid setups, positive-rake coated carbide and generous feed to break the stringy chips.
Can S420ML be welded?
Yes — weldability is rated excellent (88/100). Excellent weldability by SAW/GMAW/FCAW with low-hydrogen consumables; keep heat input moderate to protect the fine-grain TM structure, control interpass temperature and avoid post-weld normalizing.
What surface finishes work on S420ML?
Bare steel — shot blast to Sa 2½ and apply zinc-rich primer, duplex paint or hot-dip galvanizing; check silicon content before galvanizing to avoid thick brittle coatings.
Can S420ML be formed, bent or molded?
Cold-form and press-brake with bend radii per EN 10025-4 (≈2t transverse for thin plate); do not hot-form above about 580 °C or the TM strength is lost and re-normalizing is not permitted.
What is the maximum service temperature of S420ML?
S420ML is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does S420ML cost?
S420ML is a budget-cost steel ($), 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 10164 Steel products with improved deformation properties perpendicular to the surface — CEN (2018)
- EN 1993-1-1 / EN 1993-1-10 Eurocode 3 (design values, material toughness selection) — CEN (2005)
- EN 1011-2 Welding — Recommendations for arc welding of ferritic steels — CEN (2001)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Thermomechanically rolled fine-grain structural steel plate datasheets (S420M/ML class) — 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.