Steel P355GH Q&T (Quenched and tempered)
Heat-treated state
EN P355GH · ASTM A516 Grade 70 · GB Q345R
Optional accelerated-cooled/quenched and tempered route for thick plate or forged parts where higher through-thickness strength and toughness are agreed with the mill.
Values for the Q&T condition
Other P355GH tempers and conditions
P355GH is listed in 5 conditions; see the grade overview at P355GH.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/sub-critical anneal (soft, stress-free) | Choose for maximum softness and dimensional stability before heavy cold forming or machining; strength drops toward the spec minimum. | 320 | 500 | 30 | 140 HB | 8.3 % IACS |
Normalized and tempered | Normalized then tempered/PWHT-simulated; used for heavy sections and post-weld heat-treated vessels needing stable elevated-temperature properties. | 375 | 530 | 27 | 155 HB | 8.2 % IACS |
HRDefault Hot rolled | As-rolled thin plate/strip where normalizing is waived by thickness or agreement; slightly coarser and less uniform properties than +N. | 385 | 550 | 24 | 165 HB | 8.2 % IACS |
Normalized (standard EN 10028-2 delivery condition) | Standard supply condition for P355GH plate: uniform fine-grained ferrite-pearlite giving guaranteed ReH 355 MPa and RT impact energy for code vessels. | 390 | 545 | 26 | 160 HB | — |
Q&TThis page Quenched and tempered | Optional accelerated-cooled/quenched and tempered route for thick plate or forged parts where higher through-thickness strength and toughness are agreed with the mill. | 450 | 600 | 24 | 12 HRC | — |
What is P355GH Q&T?
P355GH Q&T is P355GH heat treated to Q&T — optional accelerated-cooled/quenched and tempered route for thick plate or forged parts where higher through-thickness strength and toughness are agreed with the mill. P355GH Q&T has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 52% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi). P355GH Q&T 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). HR is the default condition FabDigit quotes; Q&T is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Readily welded — 85/100, better than 83% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
P355GH Q&T properties
Typical room-temperature values for P355GH Q&T; 10 are specific to this condition. Other listed values are P355GH reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
P355GH Q&T 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
P355GH Q&T has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 52% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P355GH Q&T is rated for continuous service to 400°C (752 °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
P355GH Q&T conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of P355GH Q&T takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
P355GH Q&T's machinability is good (58/100, better than 75% of steel grades); weldability excellent (85/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with P355GH Q&T
Is P355GH easy to machine?
Machines like ordinary C-Mn plate steel at ~65 % of AISI 1212; use rigid setups and coated carbide, watch for gummy chips at low Mn-S levels.
Can P355GH be welded?
Very good weldability by SMAW/SAW/GMAW with matching low-hydrogen consumables; preheat 100–150 °C for t >30 mm or high restraint, PWHT 550–620 °C per EN 13445/AD 2000.
Can P355GH be formed, bent or molded?
Cold forms and rolls readily to about 3t bend radius; hot form 850–1000 °C followed by re-normalizing to restore certified properties.
What surface finishes work on P355GH?
No anodizing — shot-blast to Sa 2½ and paint, metallize or hot-dip galvanize; internal surfaces usually run with a corrosion allowance or weld overlay.
P355GH 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 10028-2 | ≤ 0.2 | 0.16 |
| Si | ≤ 0.6 | 0.35 |
| Mn | 1.1 – 1.7 | 1.4 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| Altotal Al | ≥ 0.02 | 0.03 |
| Cr | ≤ 0.3 | 0.1 |
| Cu | ≤ 0.3 | 0.1 |
| Mo | ≤ 0.08 | 0.02 |
| Ni | ≤ 0.3 | 0.1 |
| Nb | ≤ 0.05 | 0.01 |
| Ti | ≤ 0.03 | 0.01 |
| VNb+Ti+V ≤ 0.05 total | ≤ 0.02 | 0.01 |
| N | ≤ 0.01 | 0.01 |
| Fe | balance |
P355GH Q&T — frequently asked
What is P355GH Q&T used for?
P355GH Q&T is typically used for welded boiler drums, pressure vessel shells and heads, heat exchanger shells, steam headers and piping components, air receivers and storage tanks and autoclave bodies. In short: european boiler-plate steel.
What is the yield strength of P355GH Q&T?
P355GH Q&T has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is P355GH Q&T easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like ordinary C-Mn plate steel at ~65 % of AISI 1212; use rigid setups and coated carbide, watch for gummy chips at low Mn-S levels.
Can P355GH Q&T be welded?
Yes — weldability is rated excellent (85/100). Very good weldability by SMAW/SAW/GMAW with matching low-hydrogen consumables; preheat 100–150 °C for t >30 mm or high restraint, PWHT 550–620 °C per EN 13445/AD 2000.
What surface finishes work on P355GH Q&T?
No anodizing — shot-blast to Sa 2½ and paint, metallize or hot-dip galvanize; internal surfaces usually run with a corrosion allowance or weld overlay.
Can P355GH Q&T be formed, bent or molded?
Cold forms and rolls readily to about 3t bend radius; hot form 850–1000 °C followed by re-normalizing to restore certified properties.
What is the maximum service temperature of P355GH Q&T?
P355GH Q&T 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.
Can FabDigit make parts in P355GH Q&T?
Yes — P355GH Q&T is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10028-2 Flat products made of steels for pressure purposes — Part 2: Non-alloy and alloy steels with specified elevated temperature properties — CEN (2017)
- EN 10027-2 / material number 1.0473 — CEN (2015)
- EN 13445-2/-3 Unfired pressure vessels — materials and design — CEN (2021)
- 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)
- Pressure vessel plate P355GH data sheets (Dillinger / voestalpine / Ancofer) — mill datasheets (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.