S355JR (EN 10025-2) is Europe's primary structural round steel, with properties tailored for continental engineering needs:
Yield strength: ≥355 MPa (for thickness ≤16mm), decreasing gradually to ≥335 MPa for 16–40mm bars, ensuring consistent performance in large structures.
Tensile strength: 470–630 MPa, with elongation ≥22% to absorb energy during earthquakes-a key requirement in Eurocode 8-compliant buildings.
Impact toughness: ≥27 J at 20°C (Charpy V-notch), with S355JO offering -20°C toughness (≥27 J) for Nordic countries and S355NL providing -50°C performance for arctic infrastructure.
S355JR's chemistry (0.20% max C, 1.60% max Mn) balances strength and weldability, making it ideal for bridge girders, wind turbine towers, and prefabricated steel buildings. It is often hot-rolled into 10–300mm diameters, with DIN 1027 specifying dimensional tolerances (±0.5mm for 50mm diameter). While not directly equivalent to China's Q355, their properties overlap, allowing limited interchangeability in global projects.