What is S355J2 steel?

S355J2 is a non-alloy carbon-manganese structural steel complying with EN 10025-2. The designation indicates a minimum yield strength of 355 MPa (for thicknesses ≤ 16 mm), while J2 identifies a minimum impact energy of 27 J at –20 °C on a longitudinal Charpy V specimen. Tensile strength ranges from 470 to 630 MPa, with a minimum elongation of approximately 22%.

Chemical composition and weldability

The maximum carbon content is approximately 0,20–0,22%, with manganese up to 1,60%. The carbon equivalent (CEV) does not exceed 0,45% for thicknesses up to 30 mm, ensuring excellent weldability with SMAW, GMAW (MAG), FCAW and SAW processes. For high thicknesses or severe restraint, preheating and diffusible hydrogen control according to EN 1011 are provided.

Available profile range

  • IPE and IPN: I-beams for floors and roofs.
  • HEA, HEB, HEM: wide-flange H-sections for columns and main beams.
  • UPN and UPE: C-sections for frames and bracing.
  • L-angles (equal and unequal legs), T-sections, EN 10210 / EN 10219 structural hollow sections (CHS, SHS, RHS).
  • S355J2+N plates and flats for base plates and gussets.

Delivery conditions and variants

The +N (normalised) condition ensures a fine grain and superior toughness, useful for welded joints and low temperatures. The variants S355J0 (impact toughness at 0 °C), S355K2 (40 J at –20 °C) and S355G10+M / S355G11+N (EN 10225) are suitable for offshore structures. For joints subject to through-thickness stresses (lamellar tearing), quality Z15, Z25 or Z35 according to EN 10164 is required.

Onshore applications

Industrial buildings, bridges, cranes and overhead cranes, pipe racks, refinery plants, power stations, stadiums and lattice structures. High mechanical strength allows lighter sections than S235 or S275, saving weight and foundation costs.

Offshore applications

For jackets, topsides, process modules, walkways and pipe supports, S355 steels with high toughness are used, with NORSOK M-120 / M-650 requirements and protection against marine corrosion according to EN ISO 12944 (class C5-M / Im2), using multilayer epoxy systems or hot-dip galvanising to EN ISO 1461.

CE marking and documentation

Steel structures must comply with EN 1090-1/-2 (execution classes EXC1–EXC4) and the CPR Regulation 305/2011. Supplies are accompanied by an EN 10204 3.1 certificate, with the heat number and mechanical and chemical results.

General informational content. Refer to the applicable standard, project specification and designer for material selection.

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