EN 10025-2 Grade System
EN 10025-2 is the European standard for hot rolled products of non-alloy structural steels. The grade designation encodes the essential properties: S means structural steel, the number (235 or 355) is the minimum yield strength in MPa for thickness up to 16 mm, and the suffix defines the impact requirement. The JR, J0 and J2 suffixes guarantee 27 J impact energy at +20 °C, 0 °C and -20 °C respectively.
Grade Comparison
S235JR - 235 MPa minimum yield, tensile 360-510 MPa; the economical grade for light frames and secondary members.
S355JR - 355 MPa minimum yield, tensile 470-630 MPa; the workhorse grade for structural steelwork, offering 30-40% more design strength than S235.
S355J2 - same strength as S355JR but with 27 J impact energy guaranteed at -20 °C; required for outdoor, cold climate and fatigue-loaded structures.
Why Impact Toughness Matters
Impact toughness measures the steel's ability to absorb energy without fracturing at a given temperature. In cold climates, structures such as bridges, cranes and outdoor frames can see service temperatures well below 0 °C. A JR grade, tested only at +20 °C, may become brittle at low temperature; the J2 designation is the safe choice where the minimum service temperature is at or below -20 °C, or where the design code demands it.
Angle Sections and Custom Sizes
These grades are rolled as equal and unequal angles per EN 10056-1, with sizes from 20 x 20 mm up to 250 x 250 mm:
Equal angles - identical legs, from 20 x 20 x 3 mm to 250 x 250 x 35 mm.
Unequal angles - legs of different lengths, e.g. 100 x 75 x 8 mm, for asymmetric connections.
Custom sizes - angles beyond the rolling programme can be manufactured by cutting, welding or hot rolling to drawing, with lengths cut exactly to requirement.
Applications of Each Grade
S235JR - purlins, ladders, handrails, brackets and non-critical framing.
S355JR - main bracing, truss members, tower legs and heavily loaded connections.
S355J2 - bridge components, offshore structures, crane booms and outdoor steel in cold regions.
Supply and Certification
Angles are supplied in 6 m and 12 m lengths, cut to custom lengths, and finished black, galvanized or primed. Each delivery includes mill test certificates per EN 10204 type 3.1 with the heat analysis and mechanical test results, including impact energy values for J2 grades. Traceability is maintained by stamped heat numbers on each bar.
Frequently Asked Questions
Q: What does the JR in S235JR mean?
J stands for impact test energy of 27 J and R means room temperature, so JR guarantees 27 J at +20 °C.
Q: When should I choose S355J2 instead of S355JR?
Choose S355J2 when the structure operates below about 0 °C, or when the design code requires guaranteed toughness at -20 °C.
Q: Are S235JR and S355JR weldable?
Yes, both grades weld readily by all conventional processes; the carbon equivalent stays below the level requiring preheat in normal thicknesses.
Q: Can angles be supplied in custom lengths?
Yes, cut lengths from 0.5 m upwards are available, and holes or notches can be pre-fabricated.
Q: What is the maximum angle size?
Hot rolled equal angles go up to 250 x 250 x 35 mm; larger or non-standard sections can be built up by welding plates.
Q: Do you provide EN 10204 3.1 certificates?
Yes, mill test certificates per EN 10204 type 3.1 are standard for every delivery.