EN 10025-5 S355K2W Weathering Steel Plate
EN 10025-5 S355K2W Weathering Steel Plate: Properties & Applications
Comprehensive technical data for EN 10025-5 S355K2W weather resistant steel plate including chemical composition, mechanical properties, thermal performance, international equivalents, and application guide.
Hot rolling, normalizing, cutting, welding, bending, and forming
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EN 10025-5 S355K2W Weathering Steel Plate Introduction
EN 10025-5 S355K2W is a hot-rolled structural steel with improved atmospheric corrosion resistance, designed for welded, bolted, and riveted structures exposed to the weather. This weathering steel develops a protective rust-like oxide layer (patina) under alternating wet and dry conditions, eliminating the need for painting in many environments. With a minimum yield strength of 355 MPa and guaranteed impact toughness of 27 J at -20°C (K2 category), it is suitable for bridges, buildings, containers, and architectural applications. Its composition includes copper, chromium, and nickel to enhance corrosion resistance. The steel is supplied in the normalized or normalized-rolled condition (+N) and offers excellent weldability and formability.
EN 10025-5 S355K2W Weathering Steel Plate Chemical Composition
The chemical composition of S355K2W is balanced to achieve atmospheric corrosion resistance and mechanical properties. Key alloying elements such as Cu, Cr, and Ni promote the formation of a stable patina. Grain refining elements like Al and microalloying elements (V, Nb, Ti) may be added to meet strength and toughness requirements. The maximum carbon equivalent (CEV) is typically limited to ≤0.52 to ensure good weldability.
| Element | Standard Value (wt%) | Remarks |
|---|---|---|
| C | ≤0.16 | Excess carbon impairs weldability |
| Si | ≤0.50 | Deoxidizer |
| Mn | 0.50–1.50 | Strength and hardenability |
| P | ≤0.030 | Low phosphorus for toughness |
| S | ≤0.030 | Low sulfur for cleanliness |
| Cr | 0.40–0.80 | Enhances corrosion resistance |
| Ni | ≤0.65 | Toughness and weathering |
| Cu | 0.25–0.55 | Key for patina formation |
| N | ≤0.015 | Controlled for grain refinement |
| Altotal | ≥0.020 | Minimum for deoxidation |
| V | ≤0.12 | Optional microalloy, strength; sum Nb+V+Ti ≤0.22% |
| Nb | ≤0.05 | Optional microalloy, grain refinement |
| Ti | ≤0.12 | Optional microalloy |
| Mo | ≤0.30 | Optional, enhances corrosion resistance |
EN 10025-5 S355K2W Weathering Steel Plate Thermal and Electrical Physical Properties
The following physical properties are typical for normalized S355K2W weathering steel at room temperature and elevated temperatures. Actual values may vary with composition and heat treatment. These data are provided as engineering guidelines and are not mandatory in the standard.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | at 20 °C |
| Young's Modulus (E) | 210 | GPa | at 20 °C |
| Shear Modulus (G) | 81 | GPa | at 20 °C |
| Poisson's Ratio (ν) | 0.3 | — | — |
| Thermal Expansion (α) | 12.0 × 10-6 | 1/K | 20–100 °C |
| Thermal Expansion (α) | 12.5 × 10-6 | 1/K | 20–200 °C |
| Thermal Expansion (α) | 13.0 × 10-6 | 1/K | 20–300 °C |
| Thermal Conductivity (λ) | 50 | W/(m·K) | at 20 °C |
| Thermal Conductivity (λ) | 45 | W/(m·K) | at 200 °C |
| Specific Heat Capacity (c) | 460 | J/(kg·K) | at 20 °C |
| Electrical Resistivity (ρe) | 0.20 | μΩ·m | at 20 °C |
EN 10025-5 S355K2W Weathering Steel Plate Mechanical Properties
Mechanical properties are guaranteed for the normalized condition (+N) as per EN 10025-5. Values vary with product thickness. The impact energy is measured on longitudinal Charpy V-notch specimens at -20°C. Bend test mandrel diameters are specified to ensure formability. All values are minimum unless ranges are given.
| Property | Standard Value | 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 |
| Yield Strength (ReH) | ≥295 | MPa | 100 < t ≤ 150 mm |
| Tensile Strength (Rm) | 470 – 630 | MPa | t ≤ 100 mm |
| Tensile Strength (Rm) | 450 – 600 | MPa | 100 < t ≤ 150 mm |
| Elongation (A) on Lo=5.65√So | ≥20 | % | t ≤ 16 mm |
| Elongation (A) | ≥20 | % | 16 < t ≤ 40 mm |
| Elongation (A) | ≥20 | % | 40 < t ≤ 63 mm |
| Elongation (A) | ≥19 | % | 63 < t ≤ 100 mm |
| Elongation (A) | ≥18 | % | 100 < t ≤ 150 mm |
| Bend Test (Mandrel Dia.) | a | — | t ≤ 16 mm (180° bend) |
| Bend Test (Mandrel Dia.) | 2a | — | 16 < t ≤ 40 mm |
| Bend Test (Mandrel Dia.) | 3a | — | 40 < t ≤ 63 mm |
| Bend Test (Mandrel Dia.) | 4a | — | 63 < t ≤ 80 mm |
| Charpy Impact (KV2, long.) | ≥27 | J | Test temperature -20 °C, all thicknesses |
EN 10025-5 S355K2W Weathering Steel Plate Complete Equivalent Materials & Cross References
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-5 | S355K2W | Base standard |
| Germany | DIN EN 10025-5 | S355K2W | Identical |
| UK | BS EN 10025-5 | S355K2W | Identical |
| USA | ASTM A588/A588M | Grade K | Similar weathering and toughness, some compositional differences |
| Japan | JIS G3114 | SMA490BW | Approximate; SMA490 denotes min. tensile 490 MPa (355 min yield); impact absorbed energy may differ |
| China | GB/T 4171 | Q355NH | Weather resistant steel with 355 MPa yield; impact test at 0°C; verify toughness grade |
EN 10025-5 S355K2W Weathering Steel Plate Application Introduction
S355K2W steel is ideal for load-bearing structures exposed to atmospheric corrosion where painting or coating may be difficult or unnecessary. Its self-protecting patina reduces maintenance costs over long service lives. The K2 impact toughness ensures safe use at low temperatures, making it suitable for bridges in cold climates.
Product Applications: Weathering steel plates for bridge girders, Structural sections for building frames, Railway vehicle body panels, Container corners and panels, Tubular columns for lighting poles
Processed into products: Bridge bearing plates, Bolted and welded splice joints, Load-bearing beams and columns, Shear connectors, Bent plates for architectural features, Flanges and web stiffeners
Application industries: Bridge construction, Architectural cladding and facades, Shipping containers and freight wagons, Transmission towers and poles, Industrial chimneys and ducts, Offshore structures (above splash zone), Artistic and monumental structures
EN 10025-5 S355K2W Weathering Steel Plate Similar and Alternative Weathering Steel Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-5 | S355J2W | Same yield and corrosion resistance, impact 27J at -20°C (J2); may not require normalized delivery |
| Europe | EN 10025-5 | S355J0W | Similar but impact test at 0°C |
| USA | ASTM A588/A588M | Grade B | Cor-Ten B equivalent; 345 MPa yield with similar corrosion resistance |
| USA | ASTM A242/A242M | Type 1 | Older weathering steel, min yield varies, higher phosphorus |
| Japan | JIS G3114 | SMA490AW | Atmospheric corrosion resisting steel, min yield 365 MPa for t≤16; without Ni addition |
| India | IS 11587 | Fe 355WP | Weather resistant structural steel, impact requirements may differ |
Notes:
This steel must be exposed to alternating wet/dry cycles to develop a stable patina. In continuously wet or buried conditions, corrosion protection is required. Welding procedures should consider the low carbon equivalent (typically ≤0.52) to avoid cold cracking; preheating may be necessary for thick sections. The surface oxidation layer may cause aesthetic staining of adjacent materials during initial exposure.
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