Comparison between Welded and Stainless Steel Pipes

Stainless steel pipes are largely preferred by demanding industrial applications for many beneficial features. A few of these attributes include; exceptional corrosion resistance, unmatched heat resistance, and ability to withstand harsh environmental conditions. These pipes are offered in both seamless and welded forms as per respective industrial demands. However, in order to make a decision between these two forms, it is essential that you understand their differences with respect to certain criteria.

Seamless or Welded Pipes – Which to Choose?

Let us compare welded and seamless stainless steel tubes with respect to the following:

1. Manufacturing – The fabrication process of welded stainless steel tubes involves the following:

  • Strip, sheet, or plated steel is rolled in a rotary rolling mill.
  • Once the desired shape is achieved, a high energy source, for example; electric arc, plasma arc, laser beam, or even an electron beam is utilized to melt the metal at the weld joint.
  • This is then allowed to solidify, following which a weld bead is created.
  • The weld bead created will be thicker compared to the base metal.
  • Further weld bead modification is done to achieve a standard thickness level.

On the other hand, seamless stainless steel fabrication involves the following:

  • The fabrication starts with piercing a solid block or bar of steel utilizing extrusion, drilling, and oxygen lance techniques.
  • The bore/hollow tube thus created is then extruded. This is done to expand the diameter of the bore.
  • The wall thickness of the bore is reduced after this process. 

2. Cost-effectiveness – Compared to seamless stainless steel tubes, welded tubes are cost-effective. Production and labor costs can be higher in seamless pipe manufacturing. Also, the production involves the use of several sophisticated machinery, adding to manufacturing costs. 

3. Corrosion Resistance – Seamless stainless steel tubes possess exceptional corrosion resistance compared to welded tubes. Seamless tubes are generally preferred for highly corrosion prone environments such as mining, chemical, and refinery industries. 

4. Surface Finish – Seamless tubes have better surface finishes than welded tubes. Surface roughness around the weld bead of welded pipes gives them a rough look.

The decision whether to use a seamless or welded pipe must be made considering several more factors than the ones discussed above. The wall thickness, diameter ratio, and pipe tolerances must also be considered before finalizing between the two. Closely examine your application requirements, and choose the right stainless steel pipe form that ideally fits your application.