Quick Answer
Quick Answer
EN 10210 specifies requirements for hot finished structural hollow sections (CHS, RHS, SHS) in non-alloy and fine grain structural steels. Part 1 covers technical delivery conditions; Part 2 covers tolerances, dimensions, and sectional properties. Grades range from S235H to S460NH/NLH.
EN 10210 is the primary European standard for hot finished structural hollow sections, covering circular (CHS), rectangular (RHS), and square (SHS) profiles used in steel construction. The standard is published in two parts: Part 1 (EN 10210-1) sets out technical delivery conditions including chemical composition, mechanical properties, and inspection requirements; Part 2 (EN 10210-2) defines dimensional tolerances, section dimensions, and sectional properties. Together they form the complete specification for hot-finished hollow sections intended for structural applications, including those requiring CE marking under the Construction Products Regulation.
Scope and Applicability
EN 10210 applies to hot finished circular (CHS), rectangular (RHS), and square (SHS) hollow sections with wall thickness ≥ 2 mm, for use in structural applications. The hot-finishing process reheats the formed section to above the recrystallization temperature, producing uniform grain structure throughout including corners. Products may carry CE marking under CPR when used in structural works.
The standard covers:
- Non-alloy structural steels: S235H, S275H, S355H
- Normalized fine grain structural steels: S275NH/NLH, S355NH/NLH, S420NH/NLH, S460NH/NLH
- All three hollow section profiles: CHS, RHS, SHS
- Wall thicknesses from 2 mm up to 65 mm (for tabulated properties)
The standard does not apply to cold-formed hollow sections (covered by EN 10219), seamless or welded line pipe, or precision steel tubes.
Grade Coverage
| Grade | Base Steel per EN 10025 Part | Sub-grades | Notes |
|---|---|---|---|
| S235H | Part 2 | — | Non-alloy |
| S275H | Part 2 | — | Non-alloy |
| S355H | Part 2 | — | Non-alloy |
| S275NH | Part 3 | NLH | Normalized fine grain |
| S275NLH | Part 3 | — | Normalized fine grain, −50°C impact |
| S355NH | Part 3 | NLH | Normalized fine grain |
| S355NLH | Part 3 | — | Normalized fine grain, −50°C impact |
| S420NH | Part 3 | NLH | Normalized fine grain |
| S420NLH | Part 3 | — | Normalized fine grain, −50°C impact |
| S460NH | Part 3 | NLH | Normalized fine grain |
| S460NLH | Part 3 | — | Normalized fine grain, −50°C impact |
The "H" suffix distinguishes hollow section grades from plate/section grades; the "N" prefix indicates the hollow section is made from normalized fine grain steel.
Chemical Composition Requirements
Heat (ladle) analysis. All values wt% maximum unless a range is stated.
Non-Alloy Grades (S235H, S275H, S355H)
| Grade | C max | Mn max | Si max | P max | S max | N max |
|---|---|---|---|---|---|---|
| S235H | 0.17 | 1.40 | — | 0.035 | 0.035 | 0.012 |
| S275H | 0.21 | 1.50 | — | 0.035 | 0.035 | 0.012 |
| S355H | 0.22 | 1.60 | 0.55 | 0.035 | 0.035 | 0.012 |
Note: Al ≥ 0.020% (acid-soluble) when N ≤ 0.012% is not guaranteed by other alloying elements.
Fine Grain Grades (S275NH/NLH, S355NH/NLH, S420NH/NLH, S460NH/NLH)
| Grade | C max | Si max | Mn max | P max | S max | Al min | Nb max | V max | Ti max | N max | CEV max | |---|---|---|---|---|---|---|---|---|---|---|---|---| | S275NH | 0.18 | 0.50 | 1.50 | 0.030 | 0.025 | 0.020 | 0.05 | 0.12 | 0.05 | 0.015 | 0.40 | | S275NLH | 0.18 | 0.50 | 1.50 | 0.025 | 0.020 | 0.020 | 0.05 | 0.12 | 0.05 | 0.015 | 0.40 | | S355NH | 0.20 | 0.50 | 1.65 | 0.030 | 0.025 | 0.020 | 0.05 | 0.12 | 0.05 | 0.015 | 0.43 | | S355NLH | 0.20 | 0.50 | 1.65 | 0.025 | 0.020 | 0.020 | 0.05 | 0.12 | 0.05 | 0.015 | 0.43 | | S420NH | 0.20 | 0.50 | 1.70 | 0.030 | 0.025 | 0.020 | 0.05 | 0.12 | 0.05 | 0.015 | 0.45 | | S420NLH | 0.20 | 0.50 | 1.70 | 0.025 | 0.020 | 0.020 | 0.05 | 0.12 | 0.05 | 0.015 | 0.45 | | S460NH | 0.20 | 0.60 | 1.70 | 0.030 | 0.025 | 0.020 | 0.05 | 0.12 | 0.05 | 0.025 | 0.47 | | S460NLH | 0.20 | 0.60 | 1.70 | 0.025 | 0.020 | 0.020 | 0.05 | 0.12 | 0.05 | 0.025 | 0.47 |
Note: Nb + V + Ti combined shall not exceed 0.22% for fine grain grades. The CEV (carbon equivalent value) is calculated as: CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15.
Mechanical Properties
ReH = minimum upper yield strength; Rm = tensile strength range; A = minimum elongation % (L0 = 5.65√S0).
Non-Alloy Grades
| Grade | t ≤ 16mm ReH (MPa) | t 16–40mm ReH (MPa) | t 40–65mm ReH (MPa) | Rm (MPa) | A min % |
|---|---|---|---|---|---|
| S235H | 235 | 225 | 215 | 360–510 | 26 |
| S275H | 275 | 265 | 255 | 430–580 | 23 |
| S355H | 355 | 345 | 335 | 510–680 | 22 |
Fine Grain Grades
| Grade | t ≤ 16mm ReH (MPa) | t 16–40mm ReH (MPa) | t 40–65mm ReH (MPa) | Rm (≤16mm, MPa) | A min % |
|---|---|---|---|---|---|
| S275NH/NLH | 275 | 265 | 255 | 370–530 | 24 |
| S355NH/NLH | 355 | 345 | 335 | 470–630 | 22 |
| S420NH/NLH | 420 | 400 | 390 | 520–680 | 19 |
| S460NH/NLH | 460 | 440 | 430 | 540–720 | 17 |
Tensile testing is performed per EN ISO 6892-1. For wall thickness t > 65 mm, yield strength and tensile strength requirements are subject to agreement between manufacturer and purchaser.
Impact Test Requirements
Charpy V-notch per EN ISO 148-1.
| Grade sub-designation | Test Temperature | Minimum Energy (longitudinal) |
|---|---|---|
| S235H, S275H, S355H | 0°C | 27 J |
| S275NH, S355NH, S420NH, S460NH | −20°C | 27 J |
| S275NLH, S355NLH, S420NLH, S460NLH | −50°C | 27 J |
Test frequency: one set of 3 specimens per test unit (same cast, same heat treatment, same product form and dimension). The average of the three results shall meet the minimum; one individual result may fall below the minimum, but not below 70% of the specified minimum.
Dimensional Tolerances
Per EN 10210-2.
Circular Hollow Sections (CHS)
| Dimension | Tolerance |
|---|---|
| Outside diameter D ≤ 406.4 mm | ±1.0% of D, min ±0.5 mm |
| Outside diameter D > 406.4 mm | ±0.75% of D |
| Wall thickness t ≤ 5 mm | ±10% of t, min ±0.5 mm |
| Wall thickness t > 5 mm | ±10% of t |
| Straightness | 0.2% of total length |
| Length (exact length) | +10 mm / −0 mm |
| End squareness | ≤1% of D |
| Mass (per unit length) | ±6% of nominal |
Rectangular and Square Hollow Sections (RHS/SHS)
| Dimension | Tolerance |
|---|---|
| External dimensions (b, h ≤ 100 mm) | ±1.0 mm |
| External dimensions (b, h > 100 mm) | ±1.0% of dimension |
| Wall thickness t ≤ 5 mm | ±10% of t, min ±0.5 mm |
| Wall thickness t > 5 mm | ±10% of t |
| Corner radius (outer) | ≤3t |
| Squareness of sides | ≤2 mm per 100 mm |
| Straightness | 0.2% of total length |
| Twist | ≤2 mm per 1 m length |
Additional Tests and Requirements
EN 10210-1 sets out the following additional conditions applicable to all grades and profiles:
- Delivery condition: Hot finished — reheated and formed above recrystallization temperature; corner properties same as flat faces.
- Test unit: A test unit consists of products of the same cast, same heat treatment lot, and same nominal dimensions.
- Inspection documents: EN 10204 Type 3.1 (mill certificate) is standard; Type 3.2 available by agreement.
- Surface condition: No injurious defects. Light scale from hot finishing is acceptable. Section ends shall be cut square.
- Weld seam: Hot finished sections may be produced from welded or seamless mother tube; the weld seam, if present, shall not be detectable after hot finishing.
- CE marking: Harmonized under CPR for structural applications in accordance with EN 1090.
Cross-Standard Equivalents
| EN 10210 Grade | ASTM Equivalent | IS Equivalent | Notes |
|---|---|---|---|
| S235H | A500 Grade A | IS 1161 YST 210 | Lower strength class |
| S275H | A500 Grade B | IS 1161 YST 240 | Mid-strength |
| S355H | A500 Grade C | IS 1161 YST 310 | Most common structural grade |
| S355NH | A500 Grade C (notch tough) | — | Impact tested |
| S460NH | A500 Grade D | — | High strength |
ASTM A500 is cold-formed; EN 10210 is hot-finished. Mechanical properties differ. For hot-finished equivalents, consult mill data. IS 1161 covers ERW tubes.
MTC Verification Checklist
When verifying an EN 10210 Mill Test Certificate, confirm:
- Standard cited as EN 10210-1 and grade (e.g., S355NH) matches the purchase order
- Product form (CHS, RHS, SHS) and nominal dimensions match order
- Heat number traceable to product markings
- Chemical analysis (ladle) within specified limits for the grade, including CEV for fine grain grades
- Yield strength (ReH), tensile strength (Rm), and elongation (A) meet minima for the wall thickness range
- Charpy impact test result (KV in J) at the correct temperature for the sub-grade
- Delivery condition confirmed as hot-finished
- Dimensional inspection results within EN 10210-2 tolerances
- EN 10204 certificate type, signatory, and date
Frequently Asked Questions
What is the difference between EN 10210 and EN 10219?
EN 10210 covers hot finished hollow sections, meaning the tube is formed and then reheated above the recrystallization temperature. EN 10219 covers cold-formed hollow sections, which are formed at ambient temperature without subsequent heat treatment. Hot finishing produces uniform properties through the wall including at the corners, while cold-formed sections have higher yield strength at corners but different ductility. Hot finished sections are preferred for fatigue-critical applications and for welded connections at corners.
What does the 'H' suffix mean in EN 10210 grades like S355H?
The 'H' suffix designates that the grade is specifically intended for hollow sections (Hollow) as distinct from the parent plate/section grades in EN 10025. S355H has very similar composition to S355JR but is specified with properties appropriate for hollow section manufacture. The 'NH' and 'NLH' suffixes additionally indicate the use of normalized fine grain steel with impact testing at −20°C or −50°C respectively.
Can hot finished EN 10210 sections be substituted for cold-formed EN 10219 sections?
In most structural applications, yes — EN 10210 hot finished sections can substitute for EN 10219 cold-formed sections of the same grade designation. However, the dimensional tolerances differ (EN 10210 is generally tighter), and for design purposes EN 1993 (Eurocode 3) treats the two products differently in buckling calculations because of the different residual stress distributions. Check with the structural engineer before substituting.
What CE marking is required for EN 10210 hollow sections used in buildings?
Hollow sections supplied under EN 10210 for structural use in construction works in the EEA must carry CE marking under the Construction Products Regulation (EU) No 305/2011. The manufacturer must produce a Declaration of Performance (DoP) referencing EN 10210 and the relevant harmonized standard. The CE mark must appear on the product, label, or packaging.
What is the maximum wall thickness covered by EN 10210?
EN 10210 does not impose a blanket maximum wall thickness; however, the standard grade table in Part 1 gives mechanical properties up to t ≤ 65 mm. For wall thicknesses beyond this range, properties must be agreed between manufacturer and purchaser. Practically available hot-finished sections typically have wall thicknesses up to about 20–25 mm for standard production.
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