DIN 17102 WStE355 Fine
DIN 17102 WStE355 Fine-Grain Weldable High-Strength Steel Coil
Comprehensive material data for DIN 17102 WStE355 normalised fine-grain structural steel coil, including chemical composition, mechanical and physical properties, and international equivalents.
Normalising (N), cold forming, welding, machining
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DIN 17102 WStE355 Fine Introduction
WStE355 is a weldable fine-grain structural steel specified in DIN 17102, designed for cold-forming applications. It is supplied in the normalised condition and offers a minimum yield strength of 355 MPa with excellent toughness and good weldability. The fine-grain practice ensures improved strength and ductility while maintaining low carbon equivalent values (CEV), reducing the risk of cold cracking. This grade is widely used in welded steel structures such as bridges, cranes, offshore platforms, and heavy machinery where a combination of high strength, reliable low-temperature impact properties, and ease of fabrication is required. Typical delivery forms include hot-rolled coils and cut sheets.
DIN 17102 WStE355 Fine Chemical Composition
Chemical limits according to DIN 17102 for grade WStE355. Fine-grain elements (Al, Nb, V, Ti) are added to achieve grain refinement. Maximum carbon equivalent (CEV) is guaranteed for weldability. All values are in weight percent.
| Chemical Element | Standard Value | Remarks |
|---|---|---|
| C | ≤ 0.18 | Carbon |
| Si | ≤ 0.50 | Silicon |
| Mn | 0.90 – 1.65 | Manganese |
| P | ≤ 0.030 | Phosphorus |
| S | ≤ 0.025 | Sulfur |
| Altotal | ≥ 0.02 | Total aluminium, grain refining |
| Nb | ≤ 0.05 | Niobium |
| V | ≤ 0.10 | Vanadium |
| Ti | ≤ 0.03 | Titanium |
| N | ≤ 0.015 | Nitrogen |
| Cr | ≤ 0.30 | Chromium (residual) |
| Cu | ≤ 0.35 | Copper (residual) |
| Mo | ≤ 0.10 | Molybdenum (residual) |
| Ni | ≤ 0.30 | Nickel (residual) |
| Nb+V+Ti | ≤ 0.12 | Sum of micro-alloying elements |
DIN 17102 WStE355 Fine Thermal and Electrical Physical Properties
Physical properties for WStE355 grade at room temperature unless otherwise noted. Values are representative for low-alloy fine-grain steels and may vary slightly depending on exact composition and heat treatment.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Modulus of elasticity (E) | 210 | GPa | 20 °C |
| Shear modulus (G) | 81 | GPa | 20 °C |
| Poisson's ratio (ν) | 0.3 | – | 20 °C |
| Thermal expansion coefficient (α) | 12.0 | 10⁻⁶/K | 20 – 100 °C |
| Thermal expansion coefficient (α) | 12.5 | 10⁻⁶/K | 20 – 200 °C |
| Thermal expansion coefficient (α) | 13.3 | 10⁻⁶/K | 20 – 400 °C |
| Thermal conductivity (λ) | 51 | W/(m·K) | 20 °C |
| Specific heat capacity (cp) | 460 | J/(kg·K) | 20 °C |
| Electrical resistivity (ρe) | 0.20 – 0.25 | µΩ·m | 20 °C |
DIN 17102 WStE355 Fine Mechanical Properties
Mechanical properties as required by DIN 17102 for normalised WStE355. Values apply to the stated thickness range. Tensile test pieces are taken in longitudinal direction unless noted otherwise.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield strength ReH | ≥ 355 | MPa | Thickness ≤ 16 mm |
| Yield strength ReH | 345 – 355 | MPa | Thickness 16 < t ≤ 40 mm |
| Yield strength ReH | ≥ 325 | MPa | Thickness 40 < t ≤ 63 mm |
| Tensile strength Rm | 490 – 630 | MPa | Thickness ≤ 16 mm |
| Tensile strength Rm | 490 – 630 | MPa | Thickness 16 < t ≤ 63 mm |
| Elongation A5 | ≥ 22 | % | Thickness ≤ 16 mm, longitudinal |
| Elongation A5 | ≥ 21 | % | Thickness 16 < t ≤ 40 mm, longitudinal |
| Elongation A5 | ≥ 20 | % | Thickness 40 < t ≤ 63 mm, longitudinal |
| Bend test | no cracks | – | 180° bending, mandrel diameter 2a (a=thickness) for t ≤ 16 mm |
| Impact energy KV (long.) | ≥ 27 | J | -20 °C, thickness ≤ 60 mm |
| Impact energy KV (trans.) | ≥ 20 | J | -20 °C, thickness ≤ 60 mm |
DIN 17102 WStE355 Fine Fully Equivalent Material Standards and Substitutable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-3:2004 +A1:2019 | S355N (1.0545) | Normalised fine-grain structural steel; direct replacement for WStE355 |
| International | ISO 4950-2:1995 | S355N | High yield strength flat steel products; equivalent in chemistry and properties |
| Germany (obsolete) | DIN 17102:1983 | WStE355 | Original standard, replaced by EN 10025-3 |
DIN 17102 WStE355 Fine Application Introduction
WStE355 combines good strength, excellent weldability, and reliable low-temperature toughness, making it suitable for welded structural applications that involve static and dynamic loads. It is often used where weight reduction and cost-effectiveness of fabrication are required.
Product Applications: Welded I-beams, H-beams, and box girders, Bridge decks, truss members, and arches, Offshore platform legs and drilling modules, Crane booms, jibs, and chassis, Pressure vessels and penstocks, Cold-formed hollow sections (CHS, RHS, SHS)
Processed into products: Flanges and stiffeners for structural steelwork, Bracket plates and gussets, Chords and diagonals in lattice towers, Crane rail beams, Tubular joints and nodes in truss structures, Heavy-duty machine frames and supports
Application industries: Steel construction and civil engineering, Bridge building, Offshore and marine engineering, Heavy machinery and crane manufacturing, Pressure vessel and storage tank fabrication, Railway vehicle bodies and underframes
DIN 17102 WStE355 Fine Similar or Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A572/A572M | Grade 50 (345 MPa) | Low-alloy high-strength columbium-vanadium structural steel; similar strength, but not normalised as standard – impact properties may differ |
| USA | ASTM A633/A633M | Grade C (345 MPa) | Normalised high-strength low-alloy structural steel; closer toughness requirement, but minimum yield is 345 MPa |
| Japan | JIS G3106:2015 | SM490A/SM490B | Welded structural steel; yield point 325–365 MPa, comparable weldability and strength, but not specifically fine-grain treated unless B grade with low temperature toughness |
| China | GB/T 1591-2018 | Q355D | High strength low alloy structural steel; normalised or TMCP, CVN at -20°C ≥ 47 J, close match |
| UK (obsolete) | BS 4360:1990 | 50D | Weldable structural steel; similar thickness range for 355 MPa yield, comparable impact requirements |
Notes:
For improved through-thickness properties (e.g., Z15, Z25, Z35), consult the steel producer. Reducing the carbon equivalent (CEV) to ≤ 0.45 is common for enhanced weldability. When ordering, specify normalised delivery condition and the desired impact test temperature.
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