What are welded stainless steel tubes and what are their advantages?

What are welded stainless steel tubes?

Welded tubing is made by welding a seam along the length of a stainless steel strip in order to bring the two edges together and form a tube. As a result of this  design, welded tubes can be made in extremely long continuous lengths.

How are welded tubes made?

The first step in making welded stainless steel tubing is sending slabs of steel into a hot mill (up to 800m long) to produce thin narrow strips called skelp. In the second step of manufacture, a tube shape is formed by roll forming the skelp and then welding a seam down the length. This forming process is either hot or cold with the latter providing smoother finishes and tighter tolerances.

During manufacture, the wall thickness and diameter are chosen. The diameter of  welded tubes can range from tiny (e.g. hypodermic needles) to 3m (e.g. sewers).  The type of steel alloy used will determine the final properties of the tube with regard to corrosion resistance, strength, flexibility and heat resistance.

Lastly the seam can be further worked through forging or cold rolling to remove the beading. Some welded tubes are also deep drawn, in a similar process to seamless tubing in order to provide a much finer weld seam and better surface finish.

What are the advantages of welded stainless steel tubes?

Some of the advantages of welded tubing include:

  • generally less expensive and quicker to produce (due to a simpler manufacturing process)
  • easier to manufacture in long continuous tubes
  • can be made with larger diameters than seamless tubes

For what applications are welded tubes the preferred option?

Due to their lower cost, welded stainless steel tubes are the preferred choice for most applications where corrosion and high pressures are not a factor. Such applications can be found in the following industries:

  • Medical (hypodermic needles)
  • Automotive
  • Food and beverage
  • Marine
  • Pharmaceutical

Kamet specializes in welded tubes of small diameters as sheath material for sensors such as Pt100  in the above industries. For more specific examples or advice about  matching welded tubes to your application and temperature sensing needs, then please contact our advisors.

You can read more about our welded tubing product range on our product page.