The Two European Hollow-Section Standards
Structural hollow sections in Europe are supplied against two standards. EN 10210 covers hot-finished structural hollow sections of non-alloy and fine-grain steels, where the section is formed and finished at high temperature, above the recrystallisation temperature of the steel. EN 10219 covers cold-formed welded structural hollow sections, where the section is formed at or near room temperature and then welded. Both standards cover circular (CHS), square (SHS), and rectangular (RHS) sections, and both are used in construction and structural engineering, but the two products differ in tolerances, corner geometry, and design properties.
Process Differences
Hot-finished sections to EN 10210 are made by forming the steel at high temperature, either as seamless or by welding a hot-formed open section; the final hot forming refines the grain and leaves the section in a stress-free, normalized-like condition. Cold-formed sections to EN 10219 are made by bending strip or plate at room temperature and closing the section by longitudinal welding. The cold forming introduces work hardening in the corners, which raises the yield strength locally, and the standard accounts for this in the design properties. Cold-formed sections generally achieve tighter dimensional tolerances and better straightness, while hot-finished sections have larger corner radii and are preferred for connections where the corner shape matters.
Grades and Designation
Both standards use the EN 10025-style grade designations with the suffix H for hollow sections, for example S355J2H. The H suffix indicates that the grade is intended for hollow sections, and the impact test temperature follows the quality letter: S235JR, S275JR, S275J0H, S355J0H, S355J2H, S355K2H, and the fine-grain grades S460NH and S460NLH. The designation S355J2H means a minimum yield strength of 355 MPa with Charpy impact energy guaranteed at -20 C. The grade requirements for the same designation differ slightly between EN 10210 and EN 10219, so the standard must always be stated with the grade.
Part 1 and Part 2
Each standard has two parts. Part 1 is the technical delivery conditions, covering the steel grades, the chemistry, the mechanical properties, and the testing. Part 2 covers the tolerances, dimensions, and sectional properties of the sections. To specify a section completely, the buyer names the standard and part, the grade, the shape, and the dimensions, for example EN 10219-2 S355J2H SHS 100 x 100 x 5. The sectional properties used in design come from the tables of Part 2 or from the supplier's data.
Equivalents
The closest American equivalent to S355J2H structural tubing is ASTM A500 Grade C, which guarantees a 50 ksi (345 MPa) minimum yield strength; the impact test temperature and the chemistry differ, so the equivalence is practical rather than exact. In the ISO system, ISO 630-5 designates the hollow-section structural steels, with E355K2H as the ISO name corresponding to S355K2H. The Chinese equivalent of a 355 MPa cold-formed hollow section is Q355 per GB/T 6728, with the quality grade chosen by the impact requirement: grade B is tested at 20 C, while the J2 requirement of S355J2H demands -20 C, which is more demanding than the standard Q355B guarantee. For low-temperature duty, the impact test temperature must be specified explicitly, regardless of the nominal grade equivalence.
Frequently Asked Questions
Q: What is the difference between EN 10210 and EN 10219?
EN 10210 covers hot-finished structural hollow sections and EN 10219 covers cold-formed welded sections. The forming temperature drives the differences in tolerances, corner radii, and properties.
Q: What does S355J2H mean?
A hollow-section steel with a minimum yield strength of 355 MPa and Charpy impact energy guaranteed at -20 C, per the EN designation system.
Q: What sizes does EN 10219 cover?
The dimensional range is defined in EN 10219-2, which lists the tolerances, dimensions, and sectional properties of CHS, SHS, and RHS sections.
Q: What is the American equivalent of S355J2H?
ASTM A500 Grade C is the closest practical equivalent for structural tubing, with the differences in impact testing and chemistry noted.
Q: What is the Chinese equivalent of S355J2H?
The Q355 grades of GB/T 6728 for cold-formed hollow sections, with the quality grade selected to match the required impact temperature, for example Q355D for -20 C service.
Q: Which standard has tighter tolerances?
EN 10219 cold-formed sections generally achieve tighter dimensional tolerances, while EN 10210 hot-finished sections have larger corner radii and a stress-free condition.
