s355

S355 is a European structural steel grade defined in EN 10025-2 for hot-rolled, non-alloy structural steels. It denotes a structural steel with a nominal yield strength of 355 MPa and is valued for its combination of strength, toughness and weldability, making it widely used in construction and engineering projects.

The chemical composition of S355 steels is controlled to ensure good weldability and formability, with limits on carbon, manganese and other elements specified in EN 10025-2. In general, these steels are low to medium carbon and contain only small amounts of alloying elements, which helps maintain weldability while delivering the required strength.

Mechanical properties typically include a minimum yield strength of 355 MPa and a tensile strength in the range of about 470 to 630 MPa, with ductility dependent on thickness and product form. Charpy impact requirements are used to describe toughness for certain subgrades of S355. Common subclasses include S355JR (impact tested at room temperature), S355J0 (tested at 0°C) and S355J2 (tested at −20°C), each with a minimum impact energy of around 27 J at the specified temperature.

Variations of the grade exist, such as normalized or normalized/thermomechanically rolled forms (often denoted as S355N and S355NL) that specify different heat-treatment or processing conditions while maintaining the same basic strength target.

S355 is produced in formats suitable for structural use, including plates, sections (I-beams, channels, angles), bars, and hot-rolled coil. It is commonly applied in structural frames, bridges, towers, and other load-bearing members where a balance of strength, weldability and toughness is required.