Steel P420ML1 M-40-63
Grade
EN 1.8835, 10028-6
Heavy plate for thick shells and heads where TMCP still gives full L1 toughness.
Values for the M-40-63 condition
Other P420ML1 tempers and conditions
P420ML1 is listed in 6 conditions; see the grade overview at P420ML1.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M | Maximum-thickness TMCP band, usually mill-order only with agreed toughness testing. | 390 | 520 | 24 | 163 HB | 8.6 % IACS |
M | Upper thickness band for TMCP supply; check mill capability and through-thickness toughness. | 400 | 525 | 24 | 165 HB | 8.6 % IACS |
M-40-63This page M | Heavy plate for thick shells and heads where TMCP still gives full L1 toughness. | 415 | 535 | 25 | 168 HB | 8.6 % IACS |
M | Mid-thickness pressure-vessel plate; yield drops one step per EN 10028-5 thickness table. | 430 | 550 | 25 | 170 HB | 8.6 % IACS |
Stress relieved | Choose when the vessel will be post-weld heat treated; strength drops slightly and must be verified by simulated-PWHT testing. | 430 | 545 | 26 | 168 HB | 8.6 % IACS |
MDefault Thermomechanically controlled processed | Standard as-delivered TMCP plate in the thinnest thickness band — highest guaranteed yield strength. | 450 | 560 | 25 | 175 HB | 8.6 % IACS |
What is P420ML1 M-40-63?
P420ML1 M-40-63 is P420ML1 in the M-40-63 grade — heavy plate for thick shells and heads where TMCP still gives full L1 toughness. P420ML1 M-40-63 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 535 MPa (77.6 ksi) — weaker than 56% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi). P420ML1 M-40-63 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F). M is the default condition FabDigit quotes; M-40-63 is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 145 MPa·√m (132 ksi·√in), better than 95% of steel grades
- Readily welded — 87/100, better than 85% of steel grades
- Forms and bends easily — 63/100, better than 79% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
P420ML1 M-40-63 properties
Typical room-temperature values for P420ML1 M-40-63; 22 are specific to this condition. Other listed values are P420ML1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
P420ML1 M-40-63 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical16
P420ML1 M-40-63 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 535 MPa (77.6 ksi) — weaker than 56% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P420ML1 M-40-63 is rated for continuous service to 400°C (752 °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
P420ML1 M-40-63 conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of P420ML1 M-40-63 takes about 28 MJ of energy and emits 2.1 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 25%.
Manufacturability7
P420ML1 M-40-63's machinability is good (57/100, better than 71% of steel grades); weldability excellent (87/100); formability good (63/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with P420ML1 M-40-63
Is P420ML1 easy to machine?
Machines like a tough HSLA plate (~60 % of AISI 1212): use rigid setups, positive-rake coated carbide, moderate speed and generous feed to avoid work-hardened, gummy chips.
Can P420ML1 be welded?
Excellent weldability at CEV ≤ 0.45 — SAW/GMAW/SMAW with low-hydrogen consumables; keep heat input within the mill's recommended window (typically ≤ ~35–50 kJ/cm) so the TMCP HAZ retains its low-temperature toughness, and avoid unnecessary PWHT.
Can P420ML1 be formed, bent or molded?
Good cold formability for rolling shells and pressing heads with generous bend radii (≈2–3 t); hot forming above ~580 °C degrades the TMCP condition and then requires re-normalising or requalification.
What surface finishes work on P420ML1?
No natural corrosion resistance — shot-blast to Sa 2.5 and apply epoxy/PU coating, metallize or clad; galvanizing is possible but check silicon level for coating appearance.
P420ML1 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 |
|---|---|---|
| Cladle analysis max | ≤ 0.18 | 0.1 |
| Si | ≤ 0.5 | 0.3 |
| Mn | 1 – 1.7 | 1.5 |
| PML grades typically ordered ≤0.020 | ≤ 0.03 | 0.01 |
| SML1 low-S clean steel practice | ≤ 0.02 | 0 |
| Altotal Al, grain refining | ≥ 0.02 | 0.04 |
| NbNb+Ti+V ≤ 0.22 | ≤ 0.05 | 0.03 |
| Ti | ≤ 0.05 | 0.02 |
| V | ≤ 0.2 | 0.05 |
| Niaids low-temperature toughness | ≤ 0.8 | 0.3 |
| Cr | ≤ 0.3 | 0.05 |
| Mo | ≤ 0.25 | 0.08 |
| Cu | ≤ 0.7 | 0.15 |
| N | ≤ 0.03 | 0.01 |
| Fe | balance | — |
P420ML1 M-40-63 — frequently asked
What is P420ML1 M-40-63 used for?
P420ML1 M-40-63 is typically used for low-temperature reactors, gas storage and chemical process vessels. In short: 450 MPa vessel plate; weldable at CEV 0.45; mid-strength TMCP step.
What is the yield strength of P420ML1 M-40-63?
P420ML1 M-40-63 has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 535 MPa (77.6 ksi) — weaker than 56% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is P420ML1 M-40-63 easy to machine?
Reasonably — machinability is rated good (57/100, better than 71% of steel grades). Machines like a tough HSLA plate (~60 % of AISI 1212): use rigid setups, positive-rake coated carbide, moderate speed and generous feed to avoid work-hardened, gummy chips.
Can P420ML1 M-40-63 be welded?
Yes — weldability is rated excellent (87/100). Excellent weldability at CEV ≤ 0.45 — SAW/GMAW/SMAW with low-hydrogen consumables; keep heat input within the mill's recommended window (typically ≤ ~35–50 kJ/cm) so the TMCP HAZ retains its low-temperature toughness, and avoid unnecessary PWHT.
What surface finishes work on P420ML1 M-40-63?
No natural corrosion resistance — shot-blast to Sa 2.5 and apply epoxy/PU coating, metallize or clad; galvanizing is possible but check silicon level for coating appearance.
Can P420ML1 M-40-63 be formed, bent or molded?
Good cold formability for rolling shells and pressing heads with generous bend radii (≈2–3 t); hot forming above ~580 °C degrades the TMCP condition and then requires re-normalising or requalification.
What is the maximum service temperature of P420ML1 M-40-63?
P420ML1 M-40-63 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between P420ML1-M and P420ML1 M-63-80?
M is the default condition — standard as-delivered TMCP plate in the thinnest thickness band — highest guaranteed yield strength. M-63-80: upper thickness band for TMCP supply; check mill capability and through-thickness toughness. Yield strength is 450 MPa in M versus 400 MPa in M-63-80.
Sources
- EN 10028-5 — Flat products made of steels for pressure purposes, Part 5: Weldable fine grain steels, thermomechanically rolled — CEN (2017)
- EN 10164 — Steel products with improved deformation properties perpendicular to the surface — CEN (2018)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- TMCP pressure-vessel plate datasheets (P355M/P420M/P460M series) — European plate mills (2022)
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.