Stainless steel tubes are often used in applications that need the advantages of stainless steel material – low maintenance, corrosion-resistance, and versatility. Tubing can serve many purposes across a variety of industries, with two major types of stainless steel tube: welded and seamless. Here, Atlantic Stainless covers the production process and the main differences between these types of stainless steel tubing.
Manufacturing Stainless Steel Tube
Raw material begins in the form of hot extruded seamless pipe, which is then cold reduced and processed through tube reducers in a long, straight form. Cold reducing is the most effective manufacturing method for longer lengths of tubing. Rolled pipes are cut to the required lengths and cleaned to remove debris in preparation for heat treatment, which is applied to remove any stresses that could occur during the formation or welding process.
Various heat treatments can be used for tubing manufacturing, particularly annealing – this improves the structure of the metal and makes it more ductile for use in applications.
Welded stainless steel tubing is provided to the manufacturer in coils, which are then processed to improve the finish, remove debris, or for any alterations needed in the end product. Once the initial processing is complete, the coil is run through rollers to form the shape and prepare for welding.
Welded tubing can be either hot or cold-formed, and the finished results will differ depending on how it’s been prepared – for example, cold-formed stainless steel has a smoother finish and closer tolerances than hot-formed stainless steel. That said, regardless of how it was formed, the welding process will remain the same. The steps are as follows:
- Coils are separated into specific widths for the application
- Forming processes are applied
- Welding rolls are used to seal the seams of each tube
- Weld bead conditioning commences once weld is complete
- If needed (typically for thicker wall tubes), weld roll-down can be applied
- Tubes are sized to meet the required dimensions
- Tube is cut to establish the final length – common cutting methods include shear cutting and abrasive cutting
Seamless stainless steel tubing can be manufactured using a variety of methods, including piercing, gun drilling or extrusion.
Piercing: Uses a metal bar as its base material which is pierced with holes, then heated and rolled into a tube form.
Gun Drilling: This method produces the best quality tubes that typically outperform tubes produced by other means. It requires a round metal bar be inserted into a straight flute drill.
Extrusion: A steel bar is fed into a tube and worked through a die, which is both effective and efficient, although this process requires additional preparation than the other two tubing methods.
In some cases, cold forming can be utilized if the tubing has a more rare composition or unique dimensions – these methods include cold drawing and cold pilgering.
Cold Drawing: Involves using a die to alter the tube’s overall shape.
Cold Pilgering: Reduces the wall thickness of the tubing or piping.
Both of these cold forming processes typically aren’t necessary when manufacturing steel tubing, but when and if required by specific applications, are the preferred standard cold forming methods.
Applications for Stainless Steel Tubing
As aforementioned, there are numerous benefits to using stainless steel for your applications. The material’s extreme versatility and resistance to corrosion is hard to match, which is why there are so many industries utilizing it, including but not limited to:
- Architectural – Semi-Structural Construction
- Architectural – Ornamental Tubing
- Chemical Process Industry
- LNG (Liquefied Natural Gas)
- Mining and Minerals
- Nuclear Power
- Oil and Gas
Contact the Experts at Atlantic Stainless
Atlantic Stainless is a renowned distributor of stainless steel tube, bar, sheet, plate, pipe, beam, channel, and hardware. As stainless steel suppliers, we proudly offer a huge variety of high-quality products and unmatched expertise in our services.
Want to see what products we have available? Browse our catalog, search for a product, or contact us online today for help with your order.