Steel S420M ML-40-63
Grade
EN S420M
Heavy arctic/offshore plate; combine with low-hydrogen consumables and controlled heat input.
Values for the ML-40-63 condition
Other S420M tempers and conditions
S420M is listed in 6 conditions; see the grade overview at S420M.
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-40-63This page 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 ML-40-63?
S420M ML-40-63 is S420M in the ML-40-63 grade — heavy arctic/offshore plate; combine with low-hydrogen consumables and controlled heat input. S420M ML-40-63 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 53% of steel grades. Elongation at break is 23% and the elastic modulus is 210 GPa (30.5 Msi). S420M ML-40-63 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). M is the default condition FabDigit quotes; ML-40-63 is available on request or by drawing note.
Advantages
- Readily welded — 89/100, better than 89% of steel grades
- Forms and bends easily — 63/100, better than 79% of steel grades
- Tough — resists crack growth — 115 MPa·√m (104.7 ksi·√in), better than 77% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S420M ML-40-63 properties
Typical room-temperature values for S420M ML-40-63; 23 are specific to this condition. Other listed values are S420M reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S420M ML-40-63 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 ML-40-63 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 53% of steel grades. Elongation at break is 23% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S420M ML-40-63 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 ML-40-63 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 ML-40-63 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 ML-40-63's machinability is good (58/100, better than 75% of steel grades); weldability excellent (89/100); formability good (63/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S420M ML-40-63
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.
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).
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 | — |
S420M ML-40-63 — frequently asked
What is S420M ML-40-63 used for?
S420M ML-40-63 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 ML-40-63?
S420M ML-40-63 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S420M ML-40-63 easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% 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 ML-40-63 be welded?
Yes — weldability is rated excellent (89/100). 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 ML-40-63?
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 ML-40-63 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 ML-40-63?
S420M ML-40-63 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.