Steel P255QL
EN P255QL
P255QL is a quenched-and-tempered fine-grain non-alloy pressure vessel steel to EN 10028-6 (1.0452), also stocked normalized or cold-drawn plus QT.
Reference datasheet — P255QL 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 +QT condition
P255QL tempers and conditions
P255QL is supplied in 3 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Normalized | Pick when the mill supplies the low-temperature C-Mn analysis in normalized form (plate, heavy wall) and slightly lower proof strength is acceptable. | 270 | 400 | 30 | 125 HB | 10 % IACS |
+QTDefault Quenched and tempered | Standard supply condition for P255QL: use whenever guaranteed -50 °C Charpy toughness and Rp0.2 ≥ 255 MPa are required. | 290 | 420 | 28 | 135 HB | — |
Cold drawn, then quenched and tempered | For precision low-temperature tubing where tight OD/ID tolerance and better surface finish are needed; final heat treatment restores full impact toughness. | 305 | 440 | 26 | 145 HB | 10 % IACS |
What is P255QL?
P255QL is a quenched-and-tempered fine-grain non-alloy pressure vessel steel to EN 10028-6 (1.0452), also stocked normalized or cold-drawn plus QT. It is specified for vessel heads, reactor shells and high-pressure storage tanks that need strength combined with low-temperature toughness, giving 290 MPa yield, 420 MPa tensile, 28 % elongation and 135 HB (74 HRB). Weldability is good with CEV typically at or below 0.40, but heavy sections require preheat, hot forming destroys the heat-treated condition, and the steel has no corrosion resistance. Where sub-zero service matters more than strength, P215NL is the simpler normalized alternative. P255QL 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). P255QL has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 88% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
What is P255QL used for?
- pressure vessel heads
- reactor shells
- high-pressure storage tanks
- structural vessel components
Advantages
- Easy to machine — 65/100, better than 93% of steel grades
- Readily welded — 90/100, better than 90% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
Limitations
- Low strength — 290 MPa (42.1 ksi), worse than 88% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
P255QL properties
Typical room-temperature values for P255QL-+QT; bars are the position among steel grades.
Physical3
P255QL 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
P255QL has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 88% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P255QL is rated for continuous service to 300°C (572 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
P255QL 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 P255QL takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
P255QL's machinability is good (65/100, better than 93% of steel grades); weldability excellent (90/100); formability very good (70/100).
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. P255QL is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P255QL
Is P255QL easy to machine?
Machines like a normalized C-Mn steel (~70 % of AISI 1212); use sharp positive-rake carbide, moderate speeds and good chip control to avoid built-up edge on the gummy low-carbon matrix.
Can P255QL be welded?
Excellent weldability with CEV typically ≤ 0.40; use low-hydrogen consumables matching low-temperature toughness, preheat 100–150 °C for heavy walls, and keep heat input moderate to protect the -50 °C Charpy requirement (PWHT per EN 13445/13480 where required).
Can P255QL be formed, bent or molded?
Good cold bendability for tube bending and plate rolling; hot forming above ~950 °C must be followed by re-quenching and tempering to restore the specified properties.
P255QL 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 | ≤ 0.18 | 0.14 |
| Si | ≤ 0.35 | 0.25 |
| Mn | 0.5 – 1.4 | 1.1 |
| P | ≤ 0.03 | 0.02 |
| Slow S for toughness | ≤ 0.02 | 0.01 |
| Altotal Al, grain refinement | ≥ 0.02 | 0.03 |
| N | ≤ 0.01 | 0.01 |
| Crresidual | ≤ 0.3 | 0.1 |
| Curesidual | ≤ 0.3 | 0.1 |
| Niresidual | ≤ 0.3 | 0.1 |
| Moresidual | ≤ 0.08 | 0.02 |
| Nbmicro-alloying | ≤ 0.05 | 0.02 |
| Timicro-alloying | ≤ 0.04 | 0.01 |
| Vmicro-alloying | ≤ 0.05 | 0.01 |
| Fe | balance |
What surface finishes work on P255QL?
No self-protecting oxide — shot blast to Sa 2½ then zinc-rich primer, epoxy paint, hot-dip galvanizing or insulation cladding; passivation/anodizing not applicable.
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 P255QL in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.0452
How much does P255QL cost?
P255QL 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.
P255QL — frequently asked
What is P255QL used for?
P255QL is typically used for pressure vessel heads, reactor shells, high-pressure storage tanks and structural vessel components. In short: quenched-and-tempered vessel plate; strength plus -50 °C toughness; weldable at CEV ≤ 0.40.
What is the yield strength of P255QL?
P255QL has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 88% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is P255QL easy to machine?
Reasonably — machinability is rated good (65/100, better than 93% of steel grades). Machines like a normalized C-Mn steel (~70 % of AISI 1212); use sharp positive-rake carbide, moderate speeds and good chip control to avoid built-up edge on the gummy low-carbon matrix.
Can P255QL be welded?
Yes — weldability is rated excellent (90/100). Excellent weldability with CEV typically ≤ 0.40; use low-hydrogen consumables matching low-temperature toughness, preheat 100–150 °C for heavy walls, and keep heat input moderate to protect the -50 °C Charpy requirement (PWHT per EN 13445/13480 where required).
What surface finishes work on P255QL?
No self-protecting oxide — shot blast to Sa 2½ then zinc-rich primer, epoxy paint, hot-dip galvanizing or insulation cladding; passivation/anodizing not applicable.
Can P255QL be formed, bent or molded?
Good cold bendability for tube bending and plate rolling; hot forming above ~950 °C must be followed by re-quenching and tempering to restore the specified properties.
What is the maximum service temperature of P255QL?
P255QL is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does P255QL cost?
P255QL 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 10216-4 — Seamless steel tubes for pressure purposes, Part 4: Non-alloy and alloy steel tubes with specified low temperature properties — CEN (2013)
- EN 10027-2 — Designation systems for steels: numerical system (1.0452) — CEN (2015)
- EN 13480-3 / EN 13445-3 — Metallic industrial piping and unfired pressure vessels, design material data — CEN (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASTM A370 hardness/strength conversion tables — ASTM (2022)
- worldsteel LCI data for steel products — World Steel Association (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.