Steel S420ML-TM
Print state · default condition
EN S420ML
TM = thermomechanically rolled, thickness ≤ 16 mm
Standard as-delivered TM condition for thin plate and sections; highest guaranteed strength class of the grade.
Values for the TM condition
Other S420ML tempers and conditions
S420ML is listed in 4 conditions; see the grade overview at S420ML.
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 |
TMDefaultThis page 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 |
What is S420ML-TM?
S420ML-TM is S420ML in the TM condition — standard as-delivered TM condition for thin plate and sections; highest guaranteed strength class of the grade. S420ML-TM 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). S420ML-TM 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).
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-TM properties
Typical room-temperature values for S420ML-TM; 23 are specific to this condition. Other listed values are S420ML reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S420ML-TM 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-TM 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-TM 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-TM 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-TM 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-TM'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. Confirm any required mill or lot documentation when quoting.
Working with S420ML-TM
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.
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.
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 | — |
S420ML-TM — frequently asked
What is S420ML-TM used for?
S420ML-TM 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-TM?
S420ML-TM 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-TM 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-TM 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-TM?
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-TM 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-TM?
S420ML-TM 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.