Steel P355QH
EN P355QH
P355QH (1.8867) is the H-variant of the quenched and tempered EN 10028-6 P355Q steel, intended for elevated-temperature pressure duty and for thick-walled or hollow sections with section-specific qualification.
Reference datasheet — P355QH 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
P355QH tempers and conditions
P355QH is supplied in 4 conditions, soft to hard. QT is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
QT | Maximum-thickness qualification with lowest guaranteed strength; used for very thick-walled vessels where hardenability limits through-thickness properties. | 355 | 510 | 24 | 162 HB | 7.5 % IACS |
QT | Same heat treatment but standard-derated strength for heavy walls; choose for thick shells and forged hollow bodies. | 375 | 530 | 25 | 168 HB | 7.5 % IACS |
quenched, tempered and stress relieved (PWHT simulated) | Order this when the vessel will see PWHT/simulated post-weld heat treatment; slight strength loss but lower residual stress and better HIC/SCC behaviour. | 385 | 530 | 26 | 168 HB | 7.5 % IACS |
QTDefault Quenched and tempered | Standard as-delivered condition for plate, forged hollows and thick-wall tube up to 50 mm wall; full 355 MPa yield class. | 400 | 550 | 25 | 175 HB | 7.5 % IACS |
What is P355QH?
P355QH (1.8867) is the H-variant of the quenched and tempered EN 10028-6 P355Q steel, intended for elevated-temperature pressure duty and for thick-walled or hollow sections with section-specific qualification. It suits heavy-wall vessels and drums that need the 355 MPa yield class with verified properties through thickness; plate is supplied QT up to 150 mm and as QT+SR. Default values are 400 MPa yield, 550 MPa tensile, 25 % elongation, about 175 HB and 400 °C maximum service temperature, with machinability 55 and weldability 72. For low-temperature service specify P355QL1 or P355QL2 instead. P355QH 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). P355QH has a yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
What is P355QH used for?
- thick-wall pressure vessels
- boiler drums
- heavy pipe sections
Advantages
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
P355QH properties
Typical room-temperature values for P355QH-QT; bars are the position among steel grades.
Physical3
P355QH 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
P355QH has a yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P355QH is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
P355QH conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of P355QH takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
P355QH's machinability is good (55/100, better than 62% of steel grades); weldability very good (72/100); formability good (55/100).
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. P355QH is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P355QH
Is P355QH easy to machine?
Machines like a 170–200 HB Q&T low-alloy steel: coated carbide, moderate speeds, rigid setup; avoid heavy grinding that can re-temper or crack the surface.
Can P355QH be welded?
Good weldability with controlled CEV — use low-hydrogen consumables matching 355 MPa class, preheat 100–150 °C for heavy walls, cap heat input and keep interpass temperature low to protect the tempered microstructure.
Can P355QH be formed, bent or molded?
Cold forming possible with generous bend radii (≈3t) and grain-direction control; hot forming above the tempering temperature destroys the Q&T properties and requires re-quench-and-temper.
P355QH 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 | 0.15 |
| Si | ≤ 0.6 | 0.35 |
| Mn | 0.8 – 1.7 | 1.3 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Altotal Al, grain refinement | ≥ 0.02 | 0.04 |
| Cr | ≤ 0.5 | 0.25 |
| Mo | ≤ 0.5 | 0.25 |
| Ni | ≤ 1 | 0.4 |
| Cu | ≤ 0.3 | 0.1 |
| Nbmicroalloying | ≤ 0.05 | 0.02 |
| Ti | ≤ 0.05 | 0.02 |
| V | ≤ 0.08 | 0.03 |
| Bhardenability, thick sections | ≤ 0.01 | 0 |
| N | ≤ 0.02 | 0.01 |
| Zr | ≤ 0.05 | |
| Fe | balance |
What surface finishes work on P355QH?
No anodizing; blast and prime/epoxy-coat, metallize or clad for corrosion service, and control weld/HAZ hardness (<250 HV) for wet sour duty.
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 P355QH in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.886710028-6
How much does P355QH cost?
P355QH is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
P355QH — frequently asked
What is P355QH used for?
P355QH is typically used for thick-wall pressure vessels, boiler drums and heavy pipe sections. In short: heavy-wall Q&T vessel grade; rated to 400 °C service; section-qualified P355Q variant.
What is the yield strength of P355QH?
P355QH has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is P355QH easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a 170–200 HB Q&T low-alloy steel: coated carbide, moderate speeds, rigid setup; avoid heavy grinding that can re-temper or crack the surface.
Can P355QH be welded?
Yes — weldability is rated very good (72/100). Good weldability with controlled CEV — use low-hydrogen consumables matching 355 MPa class, preheat 100–150 °C for heavy walls, cap heat input and keep interpass temperature low to protect the tempered microstructure.
What surface finishes work on P355QH?
No anodizing; blast and prime/epoxy-coat, metallize or clad for corrosion service, and control weld/HAZ hardness (<250 HV) for wet sour duty.
Can P355QH be formed, bent or molded?
Cold forming possible with generous bend radii (≈3t) and grain-direction control; hot forming above the tempering temperature destroys the Q&T properties and requires re-quench-and-temper.
What is the maximum service temperature of P355QH?
P355QH is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does P355QH cost?
P355QH is a budget-cost steel ($), 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 made of steels for pressure purposes — Weldable fine grain steels, quenched and tempered — CEN (2017)
- EN 10222-4 / EN 10216-3 (related quenched-and-tempered pressure part grades) — CEN (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Quenched and tempered pressure vessel plate datasheets (P355Q/QH/QL1) — 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.