1. The EN 10025 Standard
EN 10025 covers hot-rolled products of structural steels, and Part 2 deals with the non-alloy structural steels including the S235, S275 and S355 families. The standard sets the chemical composition, the mechanical properties and the tolerances that apply to the delivered product, whether it is plate, sheet, bar or a rolled section such as an H-beam.
2. Properties of S355J0
S355J0 has a minimum yield strength of about 355 megapascals for ordinary thicknesses, reducing gradually as the section thickens, with a tensile strength in the range of roughly 470 to 630 megapascals and a minimum elongation of about twenty percent. The J0 suffix requires charpy impact energy of at least twenty-seven joules at zero degrees Celsius, which suits temperate climates and statically or moderately dynamically loaded structures.
3. The H-Beam Product Form
S355J0 is supplied as H-beams with parallel flanges, in European profile series and in equivalent rolled shapes. The wide flanges give good weak-axis stiffness for columns, while the parallel faces suit bolted end plates and welded splices. Designers use the section properties from the relevant profile standard when checking bending, axial capacity and buckling.
4. Applications
S355J0 H-beams are used in industrial buildings, warehouses, mezzanines, bridge girders, plant support structures, crane rails and heavy machinery frames. The grade is chosen where a general structural steel would require too large a section, but where the low-temperature toughness of J2 is not necessary. For colder service or for dynamically loaded details, S355J2 is specified instead.
5. Specification and Verification
An order should state the standard and full grade notation, the profile series and size, the delivery condition, the length and the quantity. The mill test certificate should report yield, tensile, elongation, impact energy at zero degrees and chemistry, tied to the heat number. Fabricators should qualify welding procedures and control heat input, particularly on thick flanges.
Frequently Asked Questions
Q: What does J0 mean in S355J0?
It means impact energy is tested at zero degrees Celsius, with a minimum requirement set by the standard.
Q: When should S355J2 be used instead?
For low-temperature service or dynamically loaded structures, since J2 is tested at minus twenty degrees.
Q: What is the yield strength of S355J0?
About 355 megapascals for ordinary thicknesses, decreasing as the section thickens.
Q: Is S355J0 weldable?
Yes, it is a weldable structural steel, with qualified procedures recommended on thick sections.
Q: What should the certificate include?
Yield, tensile, elongation, impact energy and chemical composition for the heat.