EN 10025-4 S355M Steel
S355M Steel: EN 10025-4 TMCP High Strength Structural Steel Data & Equivalents
Detailed material data for S355M thermomechanical rolled steel according to EN 10025-4, including chemical composition, mechanical properties, physical properties, equivalent grades and application guidance.
Thermomechanical rolling (TMCP), welding, cutting, forming, machining
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EN 10025-4 S355M Steel Introduction
S355M is a thermomechanical rolled weldable fine grain structural steel specified in EN 10025-4. It offers minimum yield strength of 355 MPa for thicknesses up to 16 mm and delivers excellent weldability, toughness, and cold forming properties.
Key features include:
- Improved notch toughness at -20°C (min 27 J)
- Fine-grain structure through controlled rolling without normalizing
- Low carbon equivalent for superior weldability
- Used in heavily loaded welded structures
This material is commonly supplied as coils, plates and sections for structural, offshore and heavy machinery applications.
EN 10025-4 S355M Steel Chemical Composition
The chemical composition of S355M is controlled to ensure good weldability and mechanical properties. Maximum values apply unless a range or minimum is indicated. The steel is fully killed and fine-grain treated, with a minimum aluminum content for grain refinement. Carbon equivalent (CEV) is typically limited to ≤0.45 for weldability.
| Chemical Element | Standard Value (wt%) | Notes |
|---|---|---|
| Carbon (C) | ≤0.14 | Max |
| Manganese (Mn) | ≤1.50 | Max |
| Silicon (Si) | ≤0.50 | Max |
| Phosphorus (P) | ≤0.030 | Max |
| Sulfur (S) | ≤0.025 | Max |
| Aluminium total (Al) | ≥0.020 | Min for grain refinement |
| Niobium (Nb) | ≤0.05 | Max |
| Vanadium (V) | ≤0.10 | Max |
| Titanium (Ti) | ≤0.05 | Max |
| Nickel (Ni) | ≤0.30 | Max |
| Chromium (Cr) | ≤0.30 | Max |
| Molybdenum (Mo) | ≤0.10 | Max |
| Copper (Cu) | ≤0.55 | Max |
| Nitrogen (N) | ≤0.015 | Max |
EN 10025-4 S355M Steel Thermal and Electrical Physical Properties
The physical constants listed below are representative of carbon-manganese structural steels like S355M. These values are not part of the EN 10025-4 specification but are widely accepted for engineering calculations. Actual values may vary slightly due to exact composition and processing history.
| Property | Value | Unit | Condition / Remarks |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | Typical at 20°C |
| Elastic modulus (E) | 200–210 | GPa | Tensile, typical |
| Shear modulus (G) | ~81 | GPa | Calculated |
| Poisson's ratio (ν) | 0.28–0.30 | – | Typical for steel |
| Thermal expansion coefficient (α) | 11.5–12.0 | 10⁻⁶/K | 20°C to 100°C |
| Thermal conductivity (λ) | 45–52 | W/(m·K) | At 20°C |
| Specific heat capacity (c) | ~460 | J/(kg·K) | At 20°C |
| Electrical resistivity (ρ_e) | 0.20–0.25 | μΩ·m | At 20°C |
EN 10025-4 S355M Steel Mechanical Properties
Mechanical properties of S355M are determined by thermomechanical processing and are thickness dependent. Values below correspond to EN 10025-4:2019 for product thickness ranges. Impact energy is measured on Charpy V-notch specimens at -20°C, with minimum average 27 J. Tensile testing is performed according to EN ISO 6892-1.
| Property | Value | Unit | Test Condition / Thickness |
|---|---|---|---|
| Yield strength (ReH) | 355 | MPa | t ≤ 16 mm |
| Yield strength (ReH) | 345 | MPa | 16 mm < t ≤ 40 mm |
| Yield strength (ReH) | 335 | MPa | 40 mm < t ≤ 63 mm |
| Yield strength (ReH) | 325 | MPa | 63 mm < t ≤ 80 mm |
| Yield strength (ReH) | 315 | MPa | 80 mm < t ≤ 100 mm |
| Yield strength (ReH) | 300 | MPa | 100 mm < t ≤ 120 mm |
| Tensile strength (Rm) | 470–630 | MPa | t ≤ 40 mm |
| Tensile strength (Rm) | 470–630 | MPa | 40 mm < t ≤ 63 mm |
| Tensile strength (Rm) | 470–630 | MPa | 63 mm < t ≤ 80 mm |
| Tensile strength (Rm) | 460–620 | MPa | 80 mm < t ≤ 100 mm |
| Tensile strength (Rm) | 450–600 | MPa | 100 mm < t ≤ 120 mm |
| Elongation (A) | 22 | % | t ≤ 40 mm (5.65√S0) |
| Elongation (A) | 21 | % | 40 mm < t ≤ 63 mm |
| Elongation (A) | 20 | % | 63 mm < t ≤ 80 mm |
| Elongation (A) | 19 | % | 80 mm < t ≤ 120 mm |
| Impact energy (KV2) at -20°C | 27 (min average) | J | t ≥ 10 mm, Charpy V |
EN 10025-4 S355M Steel Exact Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-4 | S355M | Original specification, TMCP delivery condition |
| Germany | DIN EN 10025-4 | S355M | Identical adoption |
| United Kingdom | BS EN 10025-4 | S355M | Identical adoption |
| France | NF EN 10025-4 | S355M | Identical adoption |
EN 10025-4 S355M Steel Application Introduction
S355M is a versatile high-strength structural steel particularly suited for welded constructions exposed to dynamic loading and low-temperature service. The combination of high strength, good weldability and guaranteed impact toughness makes it a preferred choice in many heavy engineering sectors.
Product Applications: Welded bridge girders and trusses, Offshore platform components (jackets, decks), Crane booms and lifting equipment, Heavy-duty vehicle chassis, Pressure vessels (if certified), Building frames and high-rise columns, Ship superstructures (non-critical)
Processed into products: Welded I-beams and box sections, Flanges and webs in plate girders, End connections and joining plates, Machined structural parts, Bolted or welded assemblies, Foundation piles and sheet piles
Application industries: Construction and Civil Engineering, Bridge Building, Offshore and Marine Engineering, Heavy Machinery Manufacturing, Transportation (rail, vehicle frames), Wind Tower and Renewable Energy Structures
EN 10025-4 S355M Steel Similar/Substitute Materials with Comparable Strength
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-2 | S355J2 | Hot-rolled; CTOD tested at -20°C; not TMCP, may require higher preheat for welding |
| Europe | EN 10025-2 | S355K2 | Hot-rolled; CTOD tested at -20°C (min 40J); better toughness than J2 |
| Europe | EN 10025-3 | S355N | Normalized/normalized rolled; good toughness but different production route |
| Europe | EN 10025-3 | S355NL | Normalized; tested at -50°C; suitable for low temperatures |
| USA | ASTM A572/A572M | Grade 50 [345] | Hot-rolled high-strength low-alloy; similar strength but no TMCP requirement |
| USA | ASTM A709/A709M | Grade 50 | Structural steel for bridges; can be produced TMCP, but specification differs |
| Japan | JIS G 3106 | SM490A | Welded structural steel; comparable tensile strength, different toughness classes |
| Japan | JIS G 3106 | SM490B | Same as SM490A but with impact test at 0°C; lower toughness than S355M |
| China | GB/T 1591 | Q355D | Low-alloy high-strength structural steel; TMCP available; impact at -20°C similar |
Notes:
Important: The data presented represent the minimum guaranteed values (where applicable). For design purposes, always refer to the latest edition of EN 10025-4 and the project-specific material specification.
Physical properties are guideline values and may differ depending on exact cast analysis and processing conditions. For dynamic loading calculations, fatigue data should be sourced from material tests or relevant design codes (e.g., EN 1993-1-9).
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