Steel P420M
EN 1.8824, 10028-5
P420M is a higher-strength thermomechanically rolled pressure vessel steel to EN 10028-5 (1.8824), delivering 445 MPa yield, 570 MPa tensile, 24 % elongation and 175 HB in the default M condition.
Reference datasheet — P420M 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
P420M tempers and conditions
P420M 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 | Heaviest standard TM-rolled class; use when wall thickness cannot be reduced further. | 410 | 545 | 23 | 168 HB | 10 % IACS |
M | Medium-thickness plate class; specified yield drops to 400 MPa. | 425 | 560 | 24 | 172 HB | 10 % IACS |
Stress relieved | Condition after PWHT of thick or highly restrained welds; expect a small loss of yield strength, so check the design allowables. | 425 | 550 | 25 | 165 HB | 10 % IACS |
MDefault Thermomechanically controlled processed | Standard supply condition for ambient / mildly cold pressure-vessel service down to -20 °C. | 445 | 570 | 24 | 175 HB | 10 % IACS |
TM rolled, low-temperature quality, impact tested at -40 °C | Choose for vessels with design temperature down to about -40 °C (tighter P/S limits). | 445 | 570 | 25 | 175 HB | 10 % IACS |
TM rolled, low-temperature quality, impact tested at -50 °C | Most demanding low-temperature grade of the family, for cold-climate or cryogenic-adjacent LPG/LNG-service vessels down to about -50 °C. | 450 | 575 | 25 | 175 HB | 10 % IACS |
What is P420M?
P420M is a higher-strength thermomechanically rolled pressure vessel steel to EN 10028-5 (1.8824), delivering 445 MPa yield, 570 MPa tensile, 24 % elongation and 175 HB in the default M condition. It is specified for large fabricated vessels where the extra yield strength reduces wall thickness and weld volume; plate is supplied in ≤16, >16-40 and >40-63 mm bands with ML1/ML2 low-temperature and SR stress-relieved options. Service is capped at 400 °C, there is no corrosion resistance, and the TM condition cannot be restored by re-normalizing after hot forming. P355M is the lower-strength, more formable alternative. P420M 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). P420M has a yield strength of 445 MPa (64.5 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 51% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
What is P420M used for?
- pressure vessels
- petrochemical reactors
- heavy tanks
Advantages
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Readily welded — 85/100, better than 83% 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
P420M properties
Typical room-temperature values for P420M-M; bars are the position among steel grades.
Physical3
P420M 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
P420M has a yield strength of 445 MPa (64.5 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 51% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P420M is rated for continuous service to 400°C (752 °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
P420M conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of P420M takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
P420M's machinability is good (58/100, better than 75% of steel grades); weldability excellent (85/100); 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. P420M is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P420M
Is P420M easy to machine?
Machines like a tough 1.5 % Mn HSLA plate — rigid setups, sharp coated carbide, moderate speeds and generous feed to avoid work hardening at drilled/bevelled edges.
Can P420M be welded?
Very good weldability with low CEV; use low-hydrogen consumables matching 420 MPa yield, control heat input to keep HAZ toughness, preheat only for heavy or restrained joints.
Can P420M be formed, bent or molded?
Cold-bendable with radii larger than mild steel; avoid hot forming or normalizing above ~580 °C because the TM-rolled strength cannot be restored by reheat treatment.
P420M 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, EN 10028-5 | ≤ 0.18 | 0.13 |
| Si | ≤ 0.5 | 0.3 |
| Mn | 1 – 1.7 | 1.5 |
| P≤0.025 for ML1, ≤0.020 for ML2 | ≤ 0.03 | 0.02 |
| S≤0.015 for ML1, ≤0.010 for ML2 | ≤ 0.03 | 0.01 |
| Altotal Al, grain refinement | ≥ 0.02 | 0.04 |
| NbNb+V+Ti ≤ 0.22 | ≤ 0.05 | 0.04 |
| V | ≤ 0.12 | 0.05 |
| Ti | ≤ 0.05 | 0.02 |
| Cr | ≤ 0.3 | 0.1 |
| Ni | ≤ 0.8 | 0.2 |
| Mo | ≤ 0.25 | 0.08 |
| Cu | ≤ 0.7 | 0.15 |
| N | ≤ 0.03 | 0.01 |
| Fe | balance |
What surface finishes work on P420M?
Blast and paint, metallize or galvanize — no inherent corrosion resistance; edges from thermal cutting should be ground before coating.
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 P420M in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.882410028-5
How much does P420M cost?
P420M 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.
P420M — frequently asked
What is P420M used for?
P420M is typically used for pressure vessels, petrochemical reactors and heavy tanks. In short: thinner walls than P355M; low-CEV pressure vessel plate; good HAZ toughness.
What is the yield strength of P420M?
P420M has a typical yield strength of 445 MPa (64.5 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 51% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is P420M easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a tough 1.5 % Mn HSLA plate — rigid setups, sharp coated carbide, moderate speeds and generous feed to avoid work hardening at drilled/bevelled edges.
Can P420M be welded?
Yes — weldability is rated excellent (85/100). Very good weldability with low CEV; use low-hydrogen consumables matching 420 MPa yield, control heat input to keep HAZ toughness, preheat only for heavy or restrained joints.
What surface finishes work on P420M?
Blast and paint, metallize or galvanize — no inherent corrosion resistance; edges from thermal cutting should be ground before coating.
Can P420M be formed, bent or molded?
Cold-bendable with radii larger than mild steel; avoid hot forming or normalizing above ~580 °C because the TM-rolled strength cannot be restored by reheat treatment.
What is the maximum service temperature of P420M?
P420M 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 P420M-M and P420M-SR?
M is the default condition — standard supply condition for ambient / mildly cold pressure-vessel service down to -20 °C. SR: condition after PWHT of thick or highly restrained welds; expect a small loss of yield strength, so check the design allowables. Yield strength is 445 MPa in M versus 425 MPa in SR.
How much does P420M cost?
P420M 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 10028-5 — Flat products made of steels for pressure purposes: weldable fine grain steels, thermomechanically rolled — CEN (2017)
- EN 10027-2 — Numerical designation system (1.8824) — CEN (2015)
- EN 13445-3 — Unfired pressure vessels: design — CEN (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Thermomechanically rolled fine-grain pressure vessel plate datasheets (P355M–P460M family) — 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.