What Is EN 10210?
EN 10210 is the European standard for hot finished structural hollow sections of non-alloy and fine grain steels. Part 1 gives the technical delivery conditions, covering chemical composition, mechanical properties, testing and inspection, while Part 2 gives dimensions and sectional properties such as tolerances, cross-sectional area and moments of inertia. The standard applies to round, square and rectangular hollow sections, and it covers both seamless and welded tube, including longitudinally submerged arc welded pipe, usually written as LSAW.
Because EN 10210 covers hot finished product, the hollow section is formed and finished above the recrystallisation temperature. The result is a normalized or normalized rolled structure with a uniform grain size, low residual stress and predictable impact toughness, which is why the standard is preferred for structures that must perform in cold climates.
How LSAW Pipe Is Manufactured
LSAW stands for longitudinal submerged arc welding, meaning the weld seam runs parallel to the pipe axis. Heavy plate is edge-milled, crimped and formed into a cylinder by the UOE route, where the plate is pressed first into a U profile and then into an O profile before the seam is closed, or by the JCOE route, where successive pressing steps create J, C and O profiles. The closed seam is welded from the inside and outside using the submerged arc process, in which the arc is shielded by a layer of fusible granular flux. The pipe is then mechanically expanded to relieve forming stress, improve roundness and straighten the body.
This route is suited to large diameters and heavy walls that resistance welded pipe cannot reach, and the single longitudinal seam can be inspected over its full length by ultrasonic or radiographic testing.
Steel Grades and Designations
The grade number states the minimum yield strength in MPa, and the suffix describes the impact test temperature and the delivery condition:
| Grade | Minimum yield strength | Notes |
|---|---|---|
| S235J0H, S235J2H | 235 MPa | Basic structural grade |
| S275J0H, S275J2H, S275NH, S275NLH | 275 MPa | Normalized variants for low temperature |
| S355J0H, S355J2H, S355K2H | 355 MPa | Most widely ordered grade |
| S355NH, S355NLH | 355 MPa | Fine grain, normalized |
| S420NH, S420NLH | 420 MPa | High strength fine grain |
| S460NH, S460NLH | 460 MPa | Highest strength level in common use |
| Suffix | Meaning |
|---|---|
| J0 | Impact tested at 0 degrees Celsius |
| J2 | Impact tested at minus 20 degrees Celsius |
| K2 | Impact tested at minus 20 degrees Celsius with a higher energy requirement |
| N | Normalized rolled delivery condition |
| NH | Normalized fine grain steel with impact testing at minus 20 degrees Celsius |
| NLH | Normalized fine grain steel with impact testing at minus 50 degrees Celsius |
| H | Hollow section |
Dimensional and Quality Characteristics
High strength from non-alloy and fine grain steel grades covering 235 MPa to 460 MPa minimum yield strength
Good weldability, supported by controlled carbon and carbon equivalent values for on-site structural connections
Excellent roundness and straightness produced by the UOE or JCOE forming route combined with mechanical expansion
Clean, uniform seam from the submerged arc process, verified by through-length non-destructive examination
Good impact toughness at low temperature, which is essential for structures in cold climates and offshore locations
Hot finished condition giving low residual stress and a stable structure for welded fabrication
Tolerances on outside diameter, wall thickness, ovality, straightness and length follow EN 10210-2. Because the section is hot finished, corner radii for square and rectangular sections differ from cold formed product, which affects connection detailing and weld access.
Typical Applications
Columns, trusses and girders in high-rise buildings, airports, stadiums and industrial halls
Bridge piers, arches and primary support members
Offshore platform jacket legs, piles and topside structures
Port, harbour and quay piling and dolphin structures
Support frames for heavy machinery and material handling systems
Wind turbine foundation components and transition pieces
Comparison with Related Standards
| Feature | EN 10210 hot finished | EN 10219 cold formed | Line pipe standards |
|---|---|---|---|
| Primary use | Structural applications | Structural applications | Oil and gas transmission |
| Forming | Hot finished from plate | Cold formed from coil or plate | Hot or cold formed |
| Typical grades | S235 to S460 with H suffix | S235 to S460 with H suffix | Grade B to X70 and higher |
| Condition | Frequently normalized | As-welded or stress relieved | As-rolled, normalized or quenched and tempered |
| Design focus | Load-bearing mechanical properties | Dimensional accuracy with good strength | Pressure containment and fracture toughness |
The two hollow section standards are not interchangeable. Hot finished pipe generally offers better toughness and lower residual stress, while cold formed pipe offers tighter dimensional control and lower cost in smaller sizes and lighter walls.
FAQ
Q: Is an EN 10210 pipe always seamless?
No. EN 10210 covers both seamless and welded hollow sections, including longitudinally submerged arc welded pipe, provided the finished product meets the hot finished delivery requirements.
Q: What does the letter H in the grade mean?
The H suffix identifies the product as a hollow section rather than plate, bar or flat product, so S355J2H is the hollow section version of the S355J2 structural grade.
Q: Which suffix should be selected for cold climate projects?
Grades with J2, K2, NH or NLH suffixes are used, because they guarantee impact energy at minus 20 degrees Celsius and, for NLH, at minus 50 degrees Celsius.
Q: Why are EN 10210 pipes often supplied normalized?
Normalizing refines the grain structure after forming and welding, which restores toughness in the heat affected zone and gives consistent mechanical properties through the wall.
Q: How is the longitudinal seam verified?
The full length of the seam is examined by ultrasonic or radiographic testing, and the pipe is dimensionally inspected against the tables in EN 10210-2.
Q: Can EN 10210 pipe be used for fluid transmission?
It can carry fluids at low to medium pressure when the design code permits, but dedicated line pipe or pressure tube standards are specified for high pressure transmission service.
