Steel P420QH
EN P420QH
P420QH (1.8936) is a nickel-alloyed, quenched-and-tempered pressure vessel plate steel from the EN 10028-6 family of weldable fine-grain steels.
Reference datasheet — P420QH 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
P420QH tempers and conditions
P420QH is supplied in 5 conditions, soft to hard. QT is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Occasionally supplied for rough machining of forgings before final quench and temper; not a pressure-retaining delivery condition. | 330 | 500 | 26 | 155 HB | 7.4 % IACS |
QT | Thick forgings and shells; lowest strength class of the grade because of reduced quench severity in the core. | 415 | 550 | 21 | 9 HRC | 7.2 % IACS |
QT | Heavy plate / medium forging section where the specified proof strength steps down with thickness. | 445 | 570 | 22 | 11 HRC | 7.2 % IACS |
Quenched and tempered plus stress relief / simulated PWHT | Order this when vessel fabrication includes post-weld heat treatment; properties are certified after the simulated PWHT cycle. | 450 | 575 | 23 | 190 HB | 7.2 % IACS |
QTDefault Quenched and tempered | Standard as-delivered condition for plate, bar and light forgings; full 420 MPa proof-strength class. | 470 | 590 | 22 | 12 HRC | 7.2 % IACS |
What is P420QH?
P420QH (1.8936) is a nickel-alloyed, quenched-and-tempered pressure vessel plate steel from the EN 10028-6 family of weldable fine-grain steels. In the Q&T condition it gives 470 MPa yield, 590 MPa tensile strength, 22 % elongation and about 195 HB, with service rated to 400 °C — more load capacity per unit wall thickness than the normalized P420NH grade. It is supplied as plate in QT, thickness-banded QT-50-100 and QT-100-160, stress-relieved QT+SR and annealed conditions. The main constraints are preheat and code PWHT on thick sections and loss of properties if hot forming exceeds the tempering temperature; P420NH is the nearest alternative where normalized supply is specified. P420QH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). P420QH has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 57% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
What is P420QH used for?
- high-pressure boilers
- pressure vessel shells
- petrochemical reactors
P420QH properties
Typical room-temperature values for P420QH-QT; bars are the position among steel grades.
Physical3
P420QH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical17
P420QH has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 57% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P420QH is rated for continuous service to 400°C (752 °F). It conducts heat at 39 W/m·K (22.5 BTU/hr·ft·°F), worse than 67% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
P420QH conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of P420QH takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 25%.
Manufacturability7
P420QH's machinability is fair (48/100, worse than 57% of steel grades); weldability good (68/100); formability fair (45/100).
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. P420QH is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P420QH
Is P420QH easy to machine?
Machines like a 200 HB Q&T alloy steel — rigid setups, coated carbide, 100–160 m/min turning, generous coolant; avoid heating above the tempering temperature during grinding.
Can P420QH be welded?
Good weldability with low-hydrogen consumables matched to 420 MPa class; preheat roughly 100–150 °C for thick sections, control interpass temperature and heat input, and use PWHT at 530–580 °C when required by code.
Can P420QH be formed, bent or molded?
Cold-form only to moderate radii (≥ 3t) and hot-form below the tempering temperature; any hot forming or normalizing requires re-quench and temper to restore properties.
P420QH 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 limit | ≤ 0.18 | 0.14 |
| Si | ≤ 0.5 | 0.3 |
| Mn | 0.8 – 1.7 | 1.3 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.01 | 0 |
| Nimain hardenability/toughness addition | ≤ 1 | 0.5 |
| Cr | ≤ 0.6 | 0.3 |
| Mo | ≤ 0.5 | 0.25 |
| Cu | ≤ 0.3 | 0.1 |
| Vmicro-alloy, sum of Nb+V+Ti limited | ≤ 0.08 | 0.03 |
| Nb | ≤ 0.05 | 0.02 |
| Ti | ≤ 0.03 | 0.01 |
| Altotal Al, grain refinement | ≥ 0.02 | 0.03 |
| N | ≤ 0.02 | 0.01 |
| B | ≤ 5×10⁻⁴ | 2×10⁻⁴ |
| Fe | balance |
What surface finishes work on P420QH?
Not anodizable; protect with blast-and-paint, epoxy/zinc-rich primer, metallizing or weld-overlay cladding for corrosive service.
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 P420QH in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.8936
How much does P420QH cost?
P420QH 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.
P420QH — frequently asked
What is P420QH used for?
P420QH is typically used for high-pressure boilers, pressure vessel shells and petrochemical reactors. In short: Q&T pressure-vessel plate; stronger than normalized P420NH; rated to 400 °C.
What is the yield strength of P420QH?
P420QH has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is P420QH easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Machines like a 200 HB Q&T alloy steel — rigid setups, coated carbide, 100–160 m/min turning, generous coolant; avoid heating above the tempering temperature during grinding.
Can P420QH be welded?
Yes — weldability is rated good (68/100). Good weldability with low-hydrogen consumables matched to 420 MPa class; preheat roughly 100–150 °C for thick sections, control interpass temperature and heat input, and use PWHT at 530–580 °C when required by code.
What surface finishes work on P420QH?
Not anodizable; protect with blast-and-paint, epoxy/zinc-rich primer, metallizing or weld-overlay cladding for corrosive service.
Can P420QH be formed, bent or molded?
Cold-form only to moderate radii (≥ 3t) and hot-form below the tempering temperature; any hot forming or normalizing requires re-quench and temper to restore properties.
What is the maximum service temperature of P420QH?
P420QH 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 P420QH-QT and P420QH-A?
QT is the default condition — standard as-delivered condition for plate, bar and light forgings; full 420 MPa proof-strength class. A: occasionally supplied for rough machining of forgings before final quench and temper; not a pressure-retaining delivery condition. Yield strength is 470 MPa in QT versus 330 MPa in A.
How much does P420QH cost?
P420QH 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 10028-6 — Flat products for pressure purposes: weldable fine grain steels, quenched and tempered — CEN (2017)
- EN 10222-4 — Steel forgings for pressure purposes: weldable fine grain steels with high proof strength — CEN (2017)
- EN 13445-3 — Unfired pressure vessels: design (physical property data) — CEN (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Quenched and tempered pressure-vessel plate datasheets (Dillinger / Industeel / SSAB type products) — various 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.