P355GH
EN 10028-2 · 1.0473
P355GH is a pressure-vessel steel (Non-Alloy High-Temp family) to EN 10028-2 (1.0473). It has a specified 0.2 % proof stress of 355 MPa and a typical tensile strength of about 510 MPa, with a uniform elongation of 22 %. Nominal carbon content is around 0.22 %. For nonlinear FEA, a bilinear model uses E = 210 GPa up to yield and a tangent modulus of 717 MPa above it. It is a general-purpose wrought steel selected on strength, cost and availability.
Bilinear material model — nonlinear FEA
Uniform elongation εu = 22.0% · conservative analysis limit ½εu = 11.0%
Bilinear (BISO) approximation. Elastic modulus E up to the 0.2% proof stress R_p0.2, then a single tangent slope Eₜ to the ultimate tensile strength: Eₜ = (Rₘ − R_p0.2) / (εu − R_p0.2/E − 0.002), where εu is the uniform elongation and Rₘ is a typical (nominal) UTS within the specified band. The half-εu figure is a conservative strain limit for the analysis. Treat these as guidance for first-pass models; for critical work use a measured true stress–strain curve for the actual product and condition.
Ratings — engineering judgement
Weldabilitygood
Designed to be welded — low carbon equivalent, fully killed and fine-grained. Preheat only for thick, restrained joints; the usual boiler/vessel welding procedures apply.
Formabilitymoderate
Good cold and hot forming for plate — dished ends, shells and cones are routine.
Machinabilitymoderate
Machines like a normalised C-Mn steel; nozzle and flange faces cut cleanly.
Corrosion resistancepoor
None inherent — internal/external protection or corrosion allowance per the vessel code.
Hardenabilitylow
Not a hardening steel; supplied normalised.
Toughnessgood
Killed, fine-grain practice gives reliable notch toughness; sub-zero impact grades available where the code needs them.
Expert notes
P355GH is the standard weldable carbon-manganese plate for boilers and pressure vessels running hot. The “GH” matters: the grade guarantees a proof stress at elevated temperature, and that hot value — not the room-temperature 355 MPa — is what your allowable stress is built on. Design to the temperature you actually operate at.
It is fully killed and fine-grained precisely so it welds predictably and holds notch toughness — this is a fabrication steel first. Normalised supply gives consistent through-thickness properties; for thick, highly restrained joints or through-thickness loading, add impact testing and Z-quality (EN 10164) as the code demands.
Think of it as the European cousin of A516 Gr 70 in role, but don’t treat them as drop-in equals — the chemistry, testing and code framework differ, so requalify rather than assume.
Above roughly 450–480 °C, creep starts to govern and plain C-Mn plate runs out of road — that is where the molybdenum grade 16Mo3 (and then the Cr-Mo steels) takes over.
Mechanical properties
| Condition | Section | Yield (MPa) |
|---|---|---|
| P355GH · normalised | t ≤ 16 mm | 355 |
| 16 < t ≤ 40 mm | 345 | |
| 40 < t ≤ 60 mm | 335 | |
| 60 < t ≤ 100 mm | 315 | |
| 100 < t ≤ 150 mm | 295 |
UTS 510–650 MPa · Impact ≥ 27 J (killed, fine grain) · Hardness ~150 HB
Physical properties
| Density | 7850 | kg/m³ |
| Elastic modulus | 210 | GPa |
| Shear modulus | 81 | GPa |
| Poisson's ratio | 0.30 | |
| Thermal expansion | 12.0 | ×10⁻⁶/°C |
| Thermal conductivity | 50 | W/(m·K) |
| Specific heat | 470 | J/(kg·K) |
Chemical composition (wt %)
Available forms
Equivalent grades
| Standard | Grade | Note |
|---|---|---|
| ASTM | A516 Gr. 70 | Nearest common US vessel plate (design philosophy differs — check). |
| DIN 17155 | 17Mn4 / HII | |
| EN 10028-2 | 1.0473 |
Historical designations
| Standard | Grade | Note |
|---|---|---|
| DIN 17155 | HII | The classic German boiler-plate designation. |
| DIN | 17Mn4 | Predecessor C-Mn vessel plate. |
Common applications
- Steam boilers and drums
- Pressure vessels and process columns
- Storage spheres and heat-exchanger shells
- Piping components for elevated-temperature service
History
P355GH descends from the HII / 17Mn4 boiler plates; EN 10028-2 harmonised Europe’s elevated-temperature pressure-vessel steels under the P…GH designations.
- 1955DIN 17155 codifies HI/HII boiler plates
- 1992EN 10028 unifies European pressure-vessel plate grades
- 2003EN 10028-2 — current form of P355GH