S355JR

S355JR is a hot-rolled structural steel grade defined in EN 10025-2. The designation JR indicates that the material has undergone Charpy V-notch impact testing at room temperature (about 20°C) and meets the corresponding toughness requirements.

The grade offers a minimum yield strength of 355 MPa and a minimum tensile strength in the range of 470–630 MPa, depending on thickness. It is a ductile, weldable steel with good formability and is commonly used in welded structures. Because JR specifies room-temperature impact testing, the material is suitable for general structural applications in moderate environments. Exact mechanical properties, including elongation, depend on product thickness and lot, so supplier data sheets should be consulted.

Chemical composition is controlled to maintain weldability and formability, with low carbon content and limited impurities. Typical ranges include carbon up to about 0.22%, manganese around 1.0–1.6%, and smaller additions of silicon, with phosphorus and sulfur kept to minimum practical levels.

Applications include construction, bridges, structural frames, towers, and other components formed by hot rolling. S355JR is supplied in forms such as plates, sections, and bars as hot-rolled products. Heat treatment is not required for standard applications, though post-weld or other heat treatments can be applied if needed.

Standards and usage: EN 10025-2 defines S355JR; the grade is widely used across Europe and in markets that adopt EN steel grades for structural applications.