Structural Celsius® 355

Celsius® 355

Celsius® 355 hot finished hollow section is manufactured exclusively from normalised, fine grain steel for outstanding performance.

Celsius® 355 is the product to choose for all critical applications where failure is simply not an option.

Available in a wide range of circular, square, rectangular and elliptical hollow sections. The strength and weldable qualities of Celsius® 355 mean that it can be used for all structural and mechanical applications, including multi-storey columns, space frames, lattice beams and frames for machinery & trailers.

Made exclusively from normalised, fine grain steel with a yield strength of 355 N/mm2, Celsius® 355 is fully stress-relieved with uniform mechanical properties and manufactured to the standard grade EN 10210 S355 NH. Other grades, including those with improved impact qualities are available on request.

  • Normalised fine grain steel, so free of internal stresses and with a minimum strength of 355 N/mm2 allowing the highest fabrication factors and enabling material cost savings and lighter structures
  • Available in a wide range of circular, square, rectangular and elliptical hollow sections
  • Tight corner radii, exceeding the standard - enhancing the product’s aesthetic appeal whilst avoiding the risk of brittle fracture which occurs in some cold formed products
  • Dimensional consistency, high levels of formability and, because the steel is fully-killed, excellent weldability
  • Certified as suitable for all structural applications, fully compliant with design codes and 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® 355, with the reassurance of batch traceability
  • Full technical support available
  • Excellent supply availability through approved stockholders
  • All Celsius® 355 material is CE marked and is fully compliant with the Construction Products Regulation
  • Suitable for galvanising

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/mm2and 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 3mm < T ≤ 100mm T ºC J  
355 470-630 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® 355 hollow sections EN10210:S355NH are subject to specific inspection and testing and are supplied with an inspection certificate type 3.1 to EN10204.

Dimensional tolerances EN10210: Part 2

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 & 3mm over every 1m length
Ellipticals: The permitted tolerance is twice the value for H<250
Maximum 0.2% of total length & 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

Tata Steel has developed software to help the design of Celsius® in structural applications.

Welded joints software

Tata Steel have developed software to enable quick assessment of welded tubular joints made with the Tata Steel Celsius® range of EN10210 S355NH hot finished structural hollow sections.

FireSoft software

Calculation of fire resistance of concrete filled tubes is not easily undertaken by hand. However the software will calculate the resistance of various types of concrete filled columns, under axial load and bending, at ambient temperature conditions and after exposure to a standard fire.

For free installation contact 01536 404561 or email

BIM: The way you want it

The DNA Profiler has been designed to allow you to access Tata Steel’s product information (3d parametric objects & data) how you want, when you want, to the level of detail you want, in the format you want.

In order to find the specific BIM file for your project – click here

Design data for structural hollow sections

The essential aid for the design of steelwork

Comprehensive section property data is provided in this ‘blue book’  as well as tables of member resistances, which are given for both Celsius® and Hybox® structural hollow sections. This enables rapid selection of steel members in compression and bending. Tables are also provided for combined bending and compression, web resistance and shear resistance. This edition provides resistances in accordance with Eurocode 3 together with the relevant UK and German National Annexes, as well as resistances to BS 5950.

Click here to access our Design data / Blue Book.

Product Downloads

Please Register or  to gain access to locked downloads.

Celsius® 355 NH technical guide image.jpg

English We have automatically detected your language settings