What is Steel Tube and how is it used?
‘Steel Tube’ are a hollow round shapes of steel section that have as the name depicts. Steel Tube uses are extensive throughout the steel fabrication industry. Steel Tube may also be called Circular Hollow Section ‘CHS’ or simply just tube or tubular section.
Typical applications of Circular Hollow Sections include anything from structural steel columns and braces to non-structural architectural metalwork.
The important dimensions are the diameter and KG per Meter (KG/M). Changes in the KG/M will have a direct effect on the wall thickness, The higher the KG/M the thicker the wall on the tube will be and thus the strength.
How are they made?
Circular Hollow Sections may be made in two different ways typically called Hot formed which are rolled at the mill in one piece and Cold formed or Electro Resistance Welded ‘ERW’ which are produced from rolled sheet or plate and welded together. Hot rolled sections are seamless and ERW or Cold Formed sections have welded seams running the length of the section, more noticeable from looking inside the section.
All our steel tubes are listed as: Diameter x Thickness.
The other important factor for strength is the material grade. The higher the numerical grade the stronger gram for gram the material will be. All structural steel applications should have the correct grade, section size and weight calculated and specified by a structural engineer.
Common grades for CHS are typically between S235 and S355. The ‘S’ in the grade means that it is Structural Steel, and the number is the minimum yield strength for example S355 has a minimum yield strength of 355Mpa (N/mm²), there are other important properties too, we have detailed this information in our technical knowledge base section here.
Types of finish
Circular hollow Sections like all steel will need to be protected from the atmosphere. Steel oxidises due to the presence of oxygen in the air and sources of moisture. As a result, in most situations they require protective treatment, most commonly this will be zinc phosphate primer, multi coat paint systems or hot dip galvanising. Other coating systems include intumescent paint to provide the steel section with fire protection for specific time periods.
We can provide all standard shapes and sizes of CHS cut to length, drilled, and finished with any coating system. Our steel design and department can provide structural calculations and drawings for your project if needed.