S355JR and S355J0 in the European Grade System
S355JR and S355J0 are two toughness classes of the same structural steel defined in EN 10025-2, the European standard for non-alloy structural steels. The base designation S355 means a minimum yield strength of 355 MPa for the thinnest material; the letters JR or J0 define the impact test temperature. S355JR is tested at +20 °C and S355J0 at 0 °C, so J0 is chosen when a structure works at low, but not arctic, service temperatures.
Both classes are supplied as hot rolled, as-rolled or normalised material, are readily weldable, and are produced as wide flange H-beams, including the HEA 900 profile, as well as plate, channel and angle sections.
Mechanical Properties
The reference thickness is the thickest element of the section, so the flange or web thickness decides which row of the table applies. The figures below are minimum values for both S355JR and S355J0.
| Thickness t (mm) | Yield strength min (MPa) |
|---|---|
| t ≤ 16 | 355 |
| 16 < t ≤ 40 | 345 |
| 40 < t ≤ 63 | 335 |
| 63 < t ≤ 80 | 325 |
| 80 < t ≤ 100 | 315 |
| 100 < t ≤ 150 | 295 |
| 150 < t ≤ 200 | 285 |
| 200 < t ≤ 250 | 275 |
| 250 < t ≤ 400 | 265 |
Tensile strength is 470-630 MPa for material up to 100 mm thick and 450-600 MPa above that. Minimum elongation on the proportional gauge length is 22 % up to 40 mm, 21 % from 40 to 63 mm and 20 % above 63 mm.
Impact Toughness Classes
| Class | Impact test temperature | Minimum Charpy V energy (J) |
|---|---|---|
| S355JR | +20 °C | 27 |
| S355J0 | 0 °C | 27 |
| S355J2 | -20 °C | 27 |
Impact energy is measured on longitudinal Charpy V-notch specimens. S355JR suits indoor and temperate applications, S355J0 gives extra margin for structures operating near 0 °C such as cold storage buildings, northern bridges and outdoor crane structures, and S355J2 is chosen when the design temperature drops below zero. None of these classes is intended for cryogenic service.
Chemical Composition
| Element max % | C | Si | Mn | P | S | N | Cu |
|---|---|---|---|---|---|---|---|
| S355JR | 0.24 | 0.55 | 1.60 | 0.035 | 0.035 | 0.012 | 0.55 |
| S355J0 | 0.20 | 0.55 | 1.60 | 0.030 | 0.030 | 0.012 | 0.55 |
The tighter carbon, phosphorus and sulphur limits of S355J0 are what support its better low temperature toughness. The low carbon and moderate manganese content keeps the steel weldable with conventional processes, and for welded structures the carbon equivalent is normally agreed between buyer and supplier according to the thickness and the welding procedure to be used.
HEA 900 as a Wide Flange Profile
HEA 900 is the 900 mm nominal height member of the HEA family of European wide flange beams. The HEA family has parallel flanges and comparatively thin walls; the HEB and HEM families share the same nominal heights but are rolled with heavier web and flange thickness for a higher load capacity at the same depth. Inside the family, a larger nominal size means a larger section height, flange width and wall thickness at the same time.
For a section 900 mm deep, the flange separation creates a long internal lever arm, which raises bending resistance and bending stiffness without adding much mass. The wide flange also improves resistance to lateral torsional buckling compared with a narrow flange beam of similar weight, and it simplifies connection detailing with bolted end plates or welded brackets.
Section properties such as area, mass per metre, second moment of area and section modulus are taken from the EN 10365 tables of European I and H sections, while dimensional tolerances follow EN 10034. HEA 900 beams are produced by hot rolling from S355JR or S355J0 feedstock and are delivered with mill test certificates to EN 10204 3.1.
Typical Applications
Beam and column frames of industrial halls, warehouses and high-rise buildings
Main girders and cross beams of road and railway bridges
Support structures of heavy machinery, cranes and conveyor systems
Cold region engineering where S355J0 toughness at 0 °C is required
Port facilities, wind power towers and photovoltaic mounting structures
Fabrication and Supply Notes
Welding is carried out with electrodes or wires matching the 355 MPa class; preheating is applied as the flange thickness and joint restraint increase.
Gas cutting, sawing and drilling are all used for detail work; cut edges are cleaned before welding and before coating.
For marine or humid atmospheres a protective system such as epoxy zinc-rich primer is recommended, while hot dip galvanizing suits outdoor structures with moderate spans.
Bolted connections normally use high strength bolting systems to EN 14399 with preloaded assemblies for dynamically loaded joints.
Frequently Asked Questions
Q: What is the difference between S355JR and S355J0?
Both have a 355 MPa minimum yield strength; S355JR is impact tested at +20 °C and S355J0 at 0 °C, and S355J0 also has tighter carbon, phosphorus and sulphur limits.
Q: What is the yield strength of S355JR?
355 MPa for material up to 16 mm thick, decreasing in steps to 265 MPa for thickness between 250 and 400 mm.
Q: Is S355J0 suitable for cold climates?
It gives a verified 27 J at 0 °C, which covers many sheltered northern applications; where the design temperature is below 0 °C the J2 class tested at -20 °C is the safer choice.
Q: What does the name HEA 900 mean?
HEA is the European wide flange family with a 900 mm nominal section height; the actual section dimensions, mass and stiffness values are read from the EN 10365 section tables.
Q: How does HEA compare with HEB?
Both have the same nominal height and flange width, but HEB has a thicker web and flange, so it carries more load with a higher mass per metre.
Q: In what condition are the beams delivered?
Hot rolled, in S355JR or S355J0, with mill test certificates to EN 10204 3.1 and dimensional tolerances to EN 10034.