Structural hollow sections

Celsius® hot finished hollow sections

Celsius® is our range of fully normalized hot finished hollow sections to EN 10210.

Celsius® is the ultimate hot finished structural hollow section. Designed to perform in the most arduous conditions, the Celsius® range have outstanding properties thanks to their fully normalized steel.

Celsius® is available in a range of grades, including the popular S355NH and weight-saving high strength S460NH. The size range available for Celsius® is one of the broadest on the market

Our team of technical experts are always on hand to help you get the most out of Celsius®. Contact us to find out how we can help you.

Tata Steel structural hollow sections in construction
Tata Steel structural hollow sections in construction
Tata Steel structural hollow sections in construction
Tata Steel structural hollow sections in construction
Product specification

EN-Construction-Product-Celsius hot finished hollow sections - Celsius S355NH

Celsius S355NH
Specification details for Celsius S355NH

EN-ConstructionEngineering-Product-Tubes-Celsius-S355NH Key features

Key features
  • Fully normalized structural hollow sections, compliant with EN 10210:S355NH
  • Normalized fine grain steel, so free of internal stresses and with a minimum strength of 355N/mm2 allowing the highest fabrication factors and enabling material cost savings and lighter structures
  • Supplied normalized and compliant to both ‘NH’ and ‘J2H’ classifications
  • Available in a wide size range of square (40 x 40 x 3.2mm to 400 x 400 x 16mm) rectangular (50 x 30 x 3.2mm to 500 x 300 x 16mm), elliptical (300 x 150 x 8mm to 500 x 250 x 16mm) and circular (42.4 x 3.2mm to 508 x 16mm) hollow sections
  • Tight corner radii (<2T) exceeding the standard - enhancing the product’s aesthetic appeal whilst avoiding the risk of brittle fracture which occurs in some cold formed products
  • Excellent dimensional consistency, high levels of formability, suitable for galvanising and, because the steel is fully-killed, excellent weldability
  • Fully compliant with CE marking and certified as suitable for all structural applications; overcomes design risks associated with other forms of hollow sections
  • Certified as suitable for mechanical applications, especially those involving cyclical loading
  • Suitable for low temperature applications (40J @ -20°C)
  • Batch-tested to give the properties of the specific delivered material; full test certification supplied
  • Clearly marked as Celsius® S355NH, and supplied with a 3.1 test certificate for the reassurance of batch traceability
  • Full technical support available
  • Excellent supply availability through approved stockholders

If you have any questions or for further information click here to contact us.

EN-ConstructionEngineering-Product-Tubes-Celsius-S355NH Mechanical Properties

Mechanical properties

High strength hot finished hollow sections suitable for all construction and mechanical applications. Celsius® 355 is suitable for all internal and external applications to BS5950-1:2000, EN1993 and BS5400.

Celsius® 355 hollow sections are supplied with a minimum yield strength of 355 N/mmand comply fully with the European Standard for hot finished structural hollow sections, EN10210:S355NH.

Yield strength;ReHmin N/mm2; Tensile strength;
Elongation % min
L0;= 5,65 √S0
Impact strength
10mm x 10mm
Carbon equivalent
(CEV) max
T ≤ 16mm T > 16mm 3mm < T ≤ 100mm T ºC J  
355 345 470-630 22 -20 40 0.43

Chemical composition % by mass

C max Si max Mn P max S max Nb max V ma Al total min Ti max Cr max Ni max Mo max Cu max N max
0.20 0.50 0.90
0.035 0.030 0.050 0.12 0.020 0.03 0.30 0.50 0.10 0.35 0.020

Celsius® 355 is produced from fully-killed steel – critical to formability and weldability.

Inspection and testing
Celsius® hollow sections EN10210:S355NH are subject to specific inspection and testing and are supplied with an inspection certificate type 3.1 to EN10204.

If you have any questions or for further information click here to contact us.

EN-Construction-Product-Tubes-Celsius-Dimensional tolerancesTSUK

Dimensional tolerances

Dimensional tolerances EN10210: Part 2

Celsius tubes are manufactured to the tolerances defined in EN 10210: Part 2. Tighter tolerances are available on request and if you require specific tolerances in excess of this, please contact us.

  Circular/Ellipticals Square/Rectangular
Outside dimension
(D B and H)
Circular ±1% with a min of ±0.5mm
and maximum of ±10mm
Ellipticals ±1% with a min of ±0.5mm
(The permitted tolerance is
twice the value for H<250)
±1% with a min of ±0.5mm
Thickness (T) -10%
Note: Positive deviation limited
by mass tolerance
Note: Positive deviation limited
by mass tolerance
Squareness of side - 90 degrees ±1 degree
External corner profile - 2T max at each corner*
(EN10210 has 3T max)
Concavity/convexity (x) - – ±1% of the side, measured
independently of the tolerance
on the outside dimension
Twist (V) Ellipticals: 2mm plus 0.5mm/m max
(The permitted tolerance is
twice the value for H<250)
2mm plus 0.5mm/m max
Section is placed on a flat surface
with one end held flat. At the other
end the height difference of 
the two lower corners is taken
Mass (M) ±6% on individual lengths ±6% on individual lengths
Straightness Maximum 0.2% of the total length and 
3mm over every 1m length
Ellipticals: The permitted tolerance is
twice the value for H<250
Maximum 0.2% of total length
and 3mm over every 1m length
Length +150mm/-0mm +150mm/-0mm
Out-of-roundness (O) Circular 2% for hollow sections having
a diameter to thickness ratio not exceeding 100

* Unless shown otherwise

EN-ConstructionEngineering-Product-Tubes-Celsius S355NH Dimensions


Celsius S355NH is available across the size range indicated in the tables, minimum order quantities may apply. Intermediate sizes may also be available. For further information or specific requests, please contact us.

Celsius S355NH is available in standard lengths from 6.0m to 14.5m for sizes up to 100/100 or 120/80 and up to 15.3m for all other sizes.

Circular hollow sections (CHS)      
mm 3.2 3.6 4 5 6.3 8 10 12.5 16 17.5
168.3              </