EN10219 S355K2H ERW Pipe
EN10219 S355K2H ERW Pipe: Properties, Composition & Equivalents
Detailed material data for S355K2H steel grade per EN 10219-1 standard for cold-formed welded structural hollow sections. Includes chemical composition, mechanical properties, physical data, equivalents, and application guide.
Can be further processed by cutting, drilling, welding, hot-dip galvanizing, painting, and bending (within limits). Suitable for all conventional joining methods.
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EN10219 S355K2H ERW Pipe Introduction
S355K2H is a fine-grain structural steel grade for cold-formed welded hollow sections, specified in EN 10219-1. It provides a minimum yield strength of 355 MPa and guaranteed impact toughness of 40 J at -20 °C (K2 designation). The grade is produced by electric resistance welding (ERW) of hot-rolled strip or plate, followed by cold forming and welding. Its high strength, excellent weldability, and good low-temperature toughness make it suitable for demanding structural applications in construction, offshore, and heavy machinery. Key features:
- Fine-grain microstructure ensuring ductility and toughness
- Low carbon equivalent (CEV ≤ 0.43 %) for good weldability
- Impact tested at -20 °C with minimum 40 J
- Available in a wide range of square, rectangular, and circular hollow sections
EN10219 S355K2H ERW Pipe Chemical Composition
Chemical composition limits according to EN 10219-1 for grade S355K2H fine grain steel, based on ladle analysis. Values apply to product thickness ≤40 mm unless otherwise agreed. Grain refinement is achieved by aluminium (min. 0.020 % total Al) or an equivalent combination of niobium, vanadium, and titanium. Residual elements are controlled to ensure good weldability and mechanical properties; the carbon equivalent (CEV) is limited to 0.43 % max.
| Chemical Element | Standard Value (max, unless min) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.22 % (t ≤ 40 mm) | Ladle analysis; for 40 < t ≤ 65 mm max 0.24 % |
| Silicon (Si) | ≤ 0.55 % | |
| Manganese (Mn) | ≤ 1.60 % | Higher Mn may be agreed for thick sections |
| Phosphorus (P) | ≤ 0.035 % | |
| Sulfur (S) | ≤ 0.035 % | |
| Nitrogen (N) | ≤ 0.009 % | For fine grain steel; total nitrogen |
| Aluminium (Al total) | ≥ 0.020 % | Or other grain refining element (Nb, V, Ti) |
| Niobium (Nb) | ≤ 0.05 % | Optional grain refiner; if used alone may be increased |
| Vanadium (V) | ≤ 0.12 % | Maximum when used with Nb or Ti; may be adjusted per option |
| Titanium (Ti) | ≤ 0.05 % | Maximum content; may be used as grain refiner |
| Chromium (Cr) | ≤ 0.30 % | Residual element, not intentionally added |
| Nickel (Ni) | ≤ 0.30 % | Residual element |
| Copper (Cu) | ≤ 0.55 % | Residual element; may be higher if agreed |
| Molybdenum (Mo) | ≤ 0.10 % | Residual element |
| Carbon Equivalent (CEV) | ≤ 0.43 % (t ≤ 40 mm) | CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 |
EN10219 S355K2H ERW Pipe Physical Properties
The following physical properties are typical for S355K2H low-alloy structural steel. They are not directly specified by EN 10219-1 but are based on standard references for carbon‑manganese steels with similar composition. Values are average at room temperature unless a temperature range is noted. Thermal and electrical data are useful for design calculations involving heat transfer, thermal expansion, or electrical resistance.
| Property | Typical Value | Unit | Test Condition / Temperature |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | 20 °C |
| Elastic Modulus (E) | 210 | GPa | 20 °C |
| Shear Modulus (G) | ≈ 80 | GPa | 20 °C |
| Poisson's Ratio (ν) | 0.3 | — | 20 °C |
| Thermal Expansion Coefficient (α) | 11.5 | 10⁻⁶/K | 20 – 100 °C |
| Thermal Expansion Coefficient (α) | 12.5 | 10⁻⁶/K | 20 – 200 °C |
| Thermal Expansion Coefficient (α) | 13.0 | 10⁻⁶/K | 20 – 300 °C |
| Thermal Conductivity (λ) | 50 | W/(m·K) | 20 °C |
| Thermal Conductivity (λ) | 47 | W/(m·K) | 100 °C |
| Specific Heat Capacity (c) | 460 | J/(kg·K) | 20 °C |
| Electrical Resistivity (ρₑ) | 0.153 | Ω·mm²/m | 20 °C |
EN10219 S355K2H ERW Pipe Mechanical Properties
Tensile and impact properties for S355K2H hollow sections in delivery condition (as-welded). Values are required minimum unless otherwise stated. Yield strength varies with wall thickness; the 355 MPa class is guaranteed up to 40 mm. Impact energy (Charpy V-notch) is validated at -20 °C with 40 J average. For bending test, full-section or strip specimens are tested; mandrel diameter depends on thickness. All data conform to EN 10219-1, Table 5.
| Property | Standard Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) – t ≤ 40 mm | ≥ 355 | MPa | Transverse direction, ambient temperature |
| Yield Strength (ReH) – 40 < t ≤ 65 mm | ≥ 345 | MPa | Transverse direction |
| Yield Strength (ReH) – 65 < t ≤ 80 mm | ≥ 335 | MPa | Transverse direction |
| Yield Strength (ReH) – 80 < t ≤ 100 mm | ≥ 325 | MPa | Transverse direction |
| Yield Strength (ReH) – 100 < t ≤ 120 mm | ≥ 315 | MPa | Transverse direction |
| Tensile Strength (Rm) – t ≤ 40 mm | 470 – 630 | MPa | Transverse direction |
| Tensile Strength (Rm) – 40 < t ≤ 65 mm | 450 – 600 | MPa | Transverse direction |
| Tensile Strength (Rm) – 65 < t ≤ 100 mm | 440 – 600 | MPa | Transverse direction (if applicable) |
| Elongation (A) – t ≤ 40 mm, long. | ≥ 20 | % | Gauge length 5.65√So, longitudinal |
| Elongation (A) – t ≤ 40 mm, trans. | ≥ 18 | % | Gauge length 5.65√So, transverse |
| Elongation (A) – 40 < t ≤ 65 mm, long. | ≥ 19 | % | Longitudinal |
| Elongation (A) – 40 < t ≤ 65 mm, trans. | ≥ 17 | % | Transverse |
| Elongation (A) – 65 < t ≤ 80 mm, long. | ≥ 18 | % | Longitudinal |
| Elongation (A) – 80 < t ≤ 100 mm, long. | ≥ 17 | % | Longitudinal |
| Impact Energy (KV) at -20 °C | ≥ 40 J (avg.), ≥ 28 J (single) | J | Charpy V-notch, longitudinal, on base material |
| Bend Test (mandrel diameter) – t ≤ 16 mm | 2t (thickness) | — | 180° bend, no cracks, full section or strip |
EN10219 S355K2H ERW Pipe Fully Equivalent Material Standards & Substitute Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10210-1 | S355K2H | Hot finished hollow section, identical mechanical properties and impact toughness |
| International | ISO 10899-1 | S355K2H | Same definition for cold formed welded hollow sections |
| Great Britain | BS EN 10219-1 | S355K2H | British adoption of EN standard |
| Germany | DIN EN 10219-1 | S355K2H | German adoption of EN standard |
EN10219 S355K2H ERW Pipe Application Introduction
S355K2H ERW pipe is ideal for load‑bearing and dynamically stressed structures. Its combination of high strength, good weldability, and reliable toughness makes it a first choice for construction, offshore, and mechanical engineering. Typical applications include:
Product Applications: Structural hollow sections (square, rectangular, circular), ERW pipes for piling and foundation, Lattice towers and masts, Scaffolding and falsework, Crane booms and jibs, Bridge components, Roll‑over protection structures (ROPS)
Processed into products: Columns, beams, and trusses in multi‑storey buildings, Bracing elements in steel frames, Offshore platform legs and braces, Pile casings and foundation pipes, Jib sections of mobile cranes, Telecommunication tower legs, Agricultural sprayer booms, Trailers and chassis rails, Conveyor gallerias and walkways
Application industries: Construction & Civil Engineering, Offshore & Marine Structures, Power Transmission & Telecommunication, Crane & Heavy Machinery Manufacturing, Agricultural Equipment, Automotive & Trailer (chassis components), Shipbuilding (non‑marine piping, structural members)
EN10219 S355K2H ERW Pipe Similar / Alternative Materials
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10219-1 | S355J2H | Same yield/tensile but impact 27 J at -20 °C (J2); suitable for less severe toughness requirements |
| Europe | EN 10219-1 | S355J0H | Same strength, impact 27 J at 0 °C; lower cost for applications not requiring sub-zero toughness |
| Europe | EN 10210-1 | S355NH | Normalized hot finished hollow section, similar strength, fine grain, but impact often at -20 °C 40 J |
| USA | ASTM A500 / A500M | Grade C (345 MPa) | Yield 345 MPa, tensile 425 MPa, no guaranteed low-temperature impact; may be substituted with careful design |
| Japan | JIS G 3466 | STKR490 | Tensile strength 490 MPa, yield ~325 MPa; square/rectangular hollow sections, not fine grain, lower yield |
Notes:
The carbon equivalent (CEV) ≤ 0.43 % ensures excellent weldability; low‑hydrogen welding processes are recommended. The grade is fully killed and fine‑grain treated. Delivery can be with mill test certificates according to EN 10204 Type 3.1 or 3.2. The product can be supplied with optional internal/external coating, bevel ends, or cut to length. For fatigue‑loaded structures, reference to EN 1993‑1‑9 is advised. Note: The physical property values are typical and may vary slightly depending on actual composition and heat treatment.
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