EN 10025-2 S355JR
S355JR is a high-strength, low-alloy structural steel defined in EN 10025-2, the European standard for hot-rolled products of non-alloy structural steels. The grade name encodes its properties: S stands for structural steel, 355 indicates a minimum yield strength of 355 MPa for thicknesses up to 16 mm, J designates impact test capability, and R means the Charpy V-notch impact test is performed at room temperature (20 degrees Celsius). S355JR is known for excellent weldability, good formability, and reliable impact resistance, which makes it one of the most widely specified structural steels in Europe for general construction, bridges, heavy machinery, and load-bearing structures in normal-temperature environments.
Chemical Composition (Ladle Analysis)
In accordance with EN 10025-2, the maximum heat (ladle) analysis values for S355JR are: carbon 0.24%, silicon 0.55%, manganese 1.60%, phosphorus 0.035%, sulfur 0.035%, nitrogen 0.012%, and copper 0.55%. The relatively low carbon content and tightly controlled impurity limits ensure good weldability and toughness, while manganese and silicon provide the required strength. These limits apply to the heat analysis; the standard specifies separate tolerances for product analysis.
Mechanical Properties by Thickness
The minimum yield strength of S355JR depends on product thickness. For thickness below 3 mm the minimum yield strength is 355 MPa with a tensile strength of 510-680 MPa. For 3-16 mm it is 355 MPa with tensile strength 470-630 MPa. The yield strength then steps down by thickness range: 345 MPa for 16-40 mm, 335 MPa for 40-63 mm, 325 MPa for 63-80 mm, 315 MPa for 80-100 mm, 295 MPa for 100-150 mm (with tensile strength 450-600 MPa), 285 MPa for 150-200 mm, 275 MPa for 200-250 mm, and 265 MPa for 250-400 mm. Charpy V-notch impact values are verified at room temperature in accordance with the standard for each thickness range.
Equivalent Grades and Standards
S355JR has well-documented equivalents in national standards. In France it corresponds to E36-2, in the United Kingdom to 50B, in Belgium to AE355-B, and in Sweden to 1412-00; the older pan-European designation Fe510-B is now outdated. In other systems, A572 Grade 50 (ASTM) offers similar strength for construction, ST52-3N (DIN) provides equivalent low-temperature toughness, SM490YA (JIS) is specified for welded structures, and Q355D (GB) matches the impact requirements. Although these grades share a similar strength level, their impact energies, delivery conditions, and testing rules differ, so equivalence should be confirmed against the governing standard before substitution.
Welding and Fabrication
S355JR is designed for welding and is one of the easiest structural steels to fabricate. Its controlled carbon content keeps the risk of weld cracking low, and standard structural welding processes such as manual metal arc, MIG/MAG, and submerged arc welding can be used with conventional consumables. The material can be cut, drilled, bent, and machined using normal workshop practice. For thicker sections and highly restrained joints, preheating and controlled cooling are recommended to maintain joint quality. The steel is commonly supplied in hot-rolled or normalized condition, in thicknesses from about 6 mm up to 300 mm depending on the mill, with options for cut-to-size, beveling, and various surface finishes.
Frequently Asked Questions
What is S355JR equivalent to? Common equivalents include A572 Grade 50 (ASTM), ST52-3N (DIN), SM490YA (JIS) and Q355D (GB); historical European designations include E36-2 (France), 50B (UK) and 1412-00 (Sweden).
What does JR mean in S355JR? J stands for impact test and R means the impact test is performed at room temperature, 20 degrees Celsius.
What is the difference between S355JR and S355J2? Both have the same strength, but S355J2 requires Charpy impact toughness of at least 27 J at minus 20 degrees Celsius, while S355JR is tested at room temperature.
Is S355 better than S275? S355 has a higher minimum yield strength, 355 MPa versus 275 MPa, so it allows lighter sections for the same load; S275 is preferred where the lower strength is sufficient.
What is S355JR used for? General construction, bridges, heavy machinery, cranes and load-bearing structures in normal-temperature environments.
What is the hardness of S355JR? Hardness is not a guaranteed property in EN 10025-2; it depends on thickness, rolling and processing conditions, and is not normally specified.
