EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel
EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel - Key Properties & Equivalent Grades
Complete technical profile of EN 10028-5 P355M weldable fine grain steel for pressure vessels, including chemical composition, mechanical and physical properties, international equivalents, and application insights.
Welding, hot forming, cold forming (within limits), flame cutting, plasma cutting, machining
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EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel Introduction
EN 10028-5 P355M is a thermomechanically rolled (M) weldable fine grain structural steel designed for pressure vessels, boilers, and related equipment. It delivers a minimum yield strength of 355 MPa with guaranteed low‑temperature toughness at -20 °C. The TMCP rolling route provides excellent weldability and uniform mechanical properties even in heavy plates, making it a cost‑effective choice for critical pressurised components.
- Standard: EN 10028-5
- Grade: P355M
- Delivery condition: thermomechanically rolled
- Typical thickness range: 3 – 100 mm (wider ranges subject to agreement)
- CEV limits ensure good cold cracking resistance
EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel Chemical Composition
All values are maximum unless a range is specified. The steel is fully killed and contains fine grain forming elements. Carbon equivalent CEV is calculated according to EN 10028-5 and normally does not exceed 0.43 for thicknesses up to 100 mm (specific agreements may apply).
| Element | Standard Value | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.14 | Max. |
| Silicon (Si) | ≤ 0.50 | Max. |
| Manganese (Mn) | 1.00 – 1.70 | Range |
| Phosphorus (P) | ≤ 0.020 | Max. |
| Sulfur (S) | ≤ 0.010 | Max. |
| Aluminium (Al total) | ≥ 0.020 | Minimum for fine grain practice |
| Nitrogen (N) | ≤ 0.015 | Max. |
| Chromium (Cr) | ≤ 0.30 | Max. |
| Copper (Cu) | ≤ 0.30 | Max. |
| Molybdenum (Mo) | ≤ 0.08 | Max. |
| Niobium (Nb) | ≤ 0.05 | Max. |
| Nickel (Ni) | ≤ 0.50 | Max. |
| Titanium (Ti) | ≤ 0.05 | Max. |
| Vanadium (V) | ≤ 0.10 | Max. |
| Nb+Ti+V | ≤ 0.12 | Sum of microalloying elements |
| Cr+Cu+Mo | ≤ 0.45 | Optional restriction for specific applications |
EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel Thermal and Electrical Physical Properties
These physical constants are representative for carbon‑manganese fine grain steels. Actual values can vary slightly depending on exact chemical composition and heat treatment. They are intended for design calculations and material modelling.
| Property | Typical Value | Unit | Test Condition / Remark |
|---|---|---|---|
| Density (ρ) | 7.85 | kg/dm³ (×10³ kg/m³) | at 20 °C |
| Modulus of elasticity (E) | 210 | GPa | at 20 °C |
| Shear modulus (G) | 81 | GPa | calculated from E and ν |
| Poisson's ratio (ν) | 0.3 | – | at 20 °C |
| Thermal expansion coefficient (α) | 11.1 | ×10⁻⁶ /K | 20 – 100 °C |
| Thermal expansion coefficient (α) | 12.2 | ×10⁻⁶ /K | 20 – 200 °C |
| Thermal expansion coefficient (α) | 13.0 | ×10⁻⁶ /K | 20 – 300 °C |
| Thermal conductivity (λ) | 52 | W/(m·K) | at 20 °C |
| Thermal conductivity (λ) | 48 | W/(m·K) | at 200 °C |
| Specific heat capacity (cₚ) | 460 | J/(kg·K) | at 20 – 100 °C |
| Electrical resistivity (ρₑ) | 0.25 | μΩ·m | at 20 °C |
EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel Mechanical Properties
Specimens are taken transverse to the rolling direction. Tensile testing according to EN ISO 6892-1, impact testing according to EN ISO 148-1 (KV₂, -20 °C). The yield strength, tensile strength and elongation values depend on product thickness. Bending test requires a crack‑free surface to at least 180°.
| Property | Standard Requirement | Unit | Test Condition / Thickness |
|---|---|---|---|
| Yield strength (ReH) | ≥ 355 | MPa | t ≤ 16 mm |
| Yield strength (ReH) | ≥ 345 | MPa | 16 < t ≤ 40 mm |
| Yield strength (ReH) | ≥ 335 | MPa | 40 < t ≤ 63 mm |
| Yield strength (ReH) | ≥ 325 | MPa | 63 < t ≤ 80 mm |
| Yield strength (ReH) | ≥ 315 | MPa | 80 < t ≤ 100 mm |
| Tensile strength (Rm) | 470 – 630 | MPa | t ≤ 100 mm |
| Elongation after fracture (A₅) | ≥ 22 | % | t ≤ 100 mm (l₀=5.65√S₀) |
| Impact energy (KV₂) | ≥ 27 (average) | J | at -20 °C, transverse |
| Bending test (bend angle 180°) | d = 1t | – | t ≤ 16 mm |
| Bending test (bend angle 180°) | d = 2t | – | 16 < t ≤ 100 mm |
EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel Completely Equivalent Materials
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10028-5 | P355M | Base standard – thermomechanically rolled |
| International | ISO 9328-5 | P355M | Technically identical to EN 10028-5 |
| Germany | DIN EN 10028-5 | P355M | Adopted European standard |
| France | NF EN 10028-5 | P355M | Adopted European standard |
| United Kingdom | BS EN 10028-5 | P355M | Adopted European standard |
EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel Application Introduction
P355M is engineered for pressurised equipment operating at moderate temperatures, normally in the range -20 °C to 400 °C. Its excellent weldability (CEV typical < 0.40) allows fabrication without excessive preheat. The steel is fully killed with fine grain practice, ensuring through‑thickness properties suitable for welded joints in heavy sections. Common fabrication routes include cold forming (within strain limits), hot forming (controlled cooling recommended), welding with matching or undermatching consumables, and post‑weld heat treatment as required by code.
Product Applications: Pressure vessels and storage tanks for elevated pressure, Steam boilers and hot water boilers, Shell‑and‑tube heat exchangers, Reactors and columns in refineries, Process piping and manifolds (when formed from plate), Autoclaves and digesters
Processed into products: Cylindrical vessel shells (rolled and welded), Dished heads and elliptical ends (hot or cold pressed), Tube sheets for heat exchangers, Flanges and stiffening rings, Support skirts and saddles, Baffle plates and separation internals, Manway covers and nozzles
Application industries: Oil & gas (upstream & downstream), Chemical and petrochemical processing, Power generation (conventional and nuclear), Heat exchanger manufacturing, Boiler and pressure vessel fabricators, Water treatment and storage
EN 10028-5 P355M: Thermomechanically Rolled Pressure Vessel & Boiler Steel Similar / Alternative Materials
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10028-3 | P355N, P355NH | Normalised fine grain steel; similar strength but toughness class may differ (N grades typically -20 °C, NH grades -20 °C and higher guaranteed hot tensile properties) |
| Europe | EN 10028-3 | P355NL1, P355NL2 | Low‑temperature versions with guaranteed impact at -40 °C / -50 °C; normalised condition |
| Europe | EN 10025-4 | S355ML | Thermomechanically rolled structural steel; similar mechanical strength but not specifically qualified for pressure vessels |
Notes:
Additional remarks:
- The steel may be supplied with enhanced through‑thickness properties (Z35 or Z25) according to EN 10164 upon agreement.
- Ultrasonic testing according to EN 10160 or equivalent is frequently specified for pressure‑containing components.
- When welding, low‑hydrogen practices and appropriate heat input control are recommended to preserve the heat‑affected zone toughness.
- For elevated‑temperature design, property reduction factors should be taken from the relevant pressure vessel code (e.g., EN 13445, ASME BPVC Section II Part D).
- This grade is not intended for long‑term use above 400 °C, where creep‑resistant grades would be required.
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