Welded Stainless Steel Tubes & Pipes vs. Seamless

Welded tubular products play a vital role in virtually every industrial segment supporting our daily lives. Stainless steel pipe and tubes have good to excellent corrosion resistance and high quality surface finish characteristics, and are for these reasons used in demanding applications such as food processing and pharmaceutical production, for the conveyance and processing of liquids, gases and semi-solids in solution. Their high strength makes them ideally suitable for pressure applications within the oil & gas, petrochemical, chemical, energy, pulp & paper industries, etc. Initially all stainless steel tubular products were of seamless construction, but with improved metallurgy and welding processes, the benefits of welded products have diminished the use of seamless. Most tubes are produced from strip material or plate and can be 100% non-destructive tested (NDT) to ensure best possible weld quality. By choosing the optimum welding procedure followed by heat treatment and chemical cleaning (pickling) the corrosion resistance of the weld equals that of the base metal. The main advantages of welded tubes and pipes are their lower inherent cost, narrower tolerances for wall thickness, concentricity (OD/ID) and internal surfaces that can be checked prior to manufacture. They also allow larger diameters and longer lengths to be produced. Although welded tubes dominate the market, seamless tubes and pipes are still used. The main reasons other than conservatism are that some very heavy wall sizes can sometimes be too thick to form to the required profiles and that some traditional standards still specify seamless. The long term future and growth of stainless steel tubular products will without a doubt lie in welded production.