Steel P355QH1
EN 1.0571, 10028-6
P355QH1 is a quenched-and-tempered fine-grain pressure vessel steel to EN 10028-6 (1.0571), with A537 Class 2 and Q345R as the nearest counterparts.
Reference datasheet — P355QH1 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
P355QH1 tempers and conditions
P355QH1 is supplied in 6 conditions, soft to hard. QT 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 |
|---|---|---|---|---|---|---|
Q+T | Maximum practical section; use where full hardenability and mid-thickness toughness must still be certified. | 355 | 520 | 24 | 160 HB | 9 % IACS |
simulated post-weld heat treatment (stress relieved) | Ordered when the vessel will be stress-relieved at 550–620 °C; properties certified after simulated PWHT cycle. | 375 | 530 | 26 | 165 HB | 9 % IACS |
Q+T | Heavy plate for thick-wall shells and forgings-substitute flanges; strength de-rated for section size. | 380 | 540 | 24 | 168 HB | 9 % IACS |
Q+T, HIC / sour-service tested | Low-sulphur, calcium-treated, HIC-tested plate for wet H2S separators and amine vessels. | 395 | 555 | 25 | 11 HRC | 9 % IACS |
QTDefault Quenched and tempered | Standard delivery condition for plate up to 50 mm; full 355 MPa minimum yield with -20 °C impact guarantee. | 400 | 560 | 25 | 175 HB | 9 % IACS |
Q+T with Z35 through-thickness ductility | Same heat treatment plus guaranteed 35 % through-thickness reduction of area for heavily restrained T-joints and nozzle reinforcements. | 400 | 560 | 24 | 175 HB | 9 % IACS |
What is P355QH1?
P355QH1 is a quenched-and-tempered fine-grain pressure vessel steel to EN 10028-6 (1.0571), with A537 Class 2 and Q345R as the nearest counterparts. The Q&T route gives 400 MPa yield, 560 MPa tensile, 25 % elongation and about 175 HB, letting designers cut wall thickness on thick-wall vessels and reactors; PWHT, Z35 through-thickness and HIC-tested conditions are on file. Weldability drops to 75/100 because heat input and PWHT must stay below the tempering temperature, service is limited to about 400 °C, and hot forming requires re-quenching and tempering. Normalized P355NH is simpler to fabricate where the extra strength is not needed. P355QH1 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). P355QH1 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 60% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
What is P355QH1 used for?
- high-pressure vessels
- thick-wall reactors
- heavy boiler drums
- chemical process equipment
Advantages
- Tough — resists crack growth — 150 MPa·√m (136.5 ksi·√in), better than 96% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
- Readily welded — 75/100, better than 76% of steel grades
P355QH1 properties
Typical room-temperature values for P355QH1-QT; bars are the position among steel grades.
Physical3
P355QH1 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).
Mechanical16
P355QH1 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 60% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P355QH1 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
P355QH1 conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of P355QH1 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
P355QH1's machinability is good (55/100, better than 62% of steel grades); weldability very good (75/100); 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. P355QH1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P355QH1
Is P355QH1 easy to machine?
Machines like a 180 HB Q&T C-Mn steel — carbide inserts, moderate speeds, rigid setups; avoid heavy grinding heat that tempers the surface.
Can P355QH1 be welded?
Good weldability with low-hydrogen SMAW/SAW/FCAW consumables; check CEV, preheat 100–150 °C above ~40 mm and limit heat input to preserve HAZ toughness; PWHT 550–620 °C, below the tempering temperature.
Can P355QH1 be formed, bent or molded?
Cold-roll shells with generous bend radii (≥3t) or hot-form at 850–950 °C followed by re-quench and temper, since hot forming destroys the delivered condition.
P355QH1 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 10028-6 | ≤ 0.16 | 0.14 |
| Si | ≤ 0.5 | 0.3 |
| Mn | 0.8 – 1.7 | 1.4 |
| PQH grade | ≤ 0.03 | 0.01 |
| SQH grade; lower for HIC plate | ≤ 0.01 | 0 |
| Altotal Al, grain refinement | ≥ 0.02 | 0.04 |
| Cr | ≤ 0.3 | 0.15 |
| Ni | ≤ 0.5 | 0.2 |
| Mo | ≤ 0.25 | 0.1 |
| Cu | ≤ 0.3 | 0.1 |
| Nbmicroalloy | ≤ 0.05 | 0.03 |
| Timicroalloy | ≤ 0.05 | 0.02 |
| Vmicroalloy | ≤ 0.08 | 0.03 |
| Bhardenability, thick plate | ≤ 0.01 | 0 |
| N | ≤ 0.02 | 0.01 |
| Fe | balance |
What surface finishes work on P355QH1?
Shot-blast to Sa 2½ and apply epoxy/zinc-rich paint, or clad/weld-overlay with stainless or Alloy 625 for corrosive process sides; no anodizing possible.
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 P355QH1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.057110028-6
- Similar grades
- A537 Class 2Q345R
How much does P355QH1 cost?
P355QH1 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.
P355QH1 — frequently asked
What is P355QH1 used for?
P355QH1 is typically used for high-pressure vessels, thick-wall reactors, heavy boiler drums and chemical process equipment. In short: highest-strength 355 vessel plate; thinner walls, heavier sections; Q&T condition limits fabrication.
What is the yield strength of P355QH1?
P355QH1 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is P355QH1 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a 180 HB Q&T C-Mn steel — carbide inserts, moderate speeds, rigid setups; avoid heavy grinding heat that tempers the surface.
Can P355QH1 be welded?
Yes — weldability is rated very good (75/100). Good weldability with low-hydrogen SMAW/SAW/FCAW consumables; check CEV, preheat 100–150 °C above ~40 mm and limit heat input to preserve HAZ toughness; PWHT 550–620 °C, below the tempering temperature.
What surface finishes work on P355QH1?
Shot-blast to Sa 2½ and apply epoxy/zinc-rich paint, or clad/weld-overlay with stainless or Alloy 625 for corrosive process sides; no anodizing possible.
Can P355QH1 be formed, bent or molded?
Cold-roll shells with generous bend radii (≥3t) or hot-form at 850–950 °C followed by re-quench and temper, since hot forming destroys the delivered condition.
What is the maximum service temperature of P355QH1?
P355QH1 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 P355QH1-QT and P355QH1 QT-PWHT?
QT is the default condition — standard delivery condition for plate up to 50 mm; full 355 MPa minimum yield with -20 °C impact guarantee. QT-PWHT: ordered when the vessel will be stress-relieved at 550–620 °C; properties certified after simulated PWHT cycle. Yield strength is 400 MPa in QT versus 375 MPa in QT-PWHT.
How much does P355QH1 cost?
P355QH1 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)
- ASTM A537/A537M Heat-Treated Carbon-Manganese-Silicon Steel Plates for Pressure Vessels — ASTM (2020)
- GB/T 713 Steel plates for boilers and pressure vessels (Q345R) — SAC (2014)
- 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)
- Quenched and tempered pressure vessel plate datasheets (Dillinger / Industeel / voestalpine) — 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.