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.
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.
Some of the advantages of welded tubing include:
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:
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.
