Welded Or Seamless Stainless Steel Tubing Should I Choose?

Stainless steel pipes are produced in two ways, either seamless or welded. You need to choose between seamless or welded based on your project requirements.
Because there are no longitudinal welds, seamless pipe is generally considered a higher integrity product than welded sanitary pipe. Seamless pipe has a 20% higher ASME working pressure than welded pipe of the same material and size.

Seamless pipes are mainly used where the standard clearly stipulates seamlessness, but current product standards are constantly being revised to adapt to modern welding manufacturing technology.

Another advantage of seamless pipe is that it offers excellent corrosion resistance as it has virtually no possibility of impurities developing. Using seamless pipe avoids the potential defects and ductility differences associated with the welded areas of welded pipe. Therefore, seamless pipe is often better suited for critical applications.

  

For decades, all stainless steel pipes were seamless. However, advances in welding and metal purification technology have led to the popularity of welded pipe.

Because less drawing and annealing is required in making welded and drawn pipe, welded stainless steel pipe costs less than seamless pipe and is generally faster to source than seamless pipe. Welded pipe is frequently used in LNG plants, terminals and tankers, GTL plants, regasification and storage and other oil and gas applications. Offshore, welded pipe is used for flowlines, umbilicals and risers below sea level. Above sea level, they are often found in process piping, seawater, and service systems.

The decision to use seamless or welded stainless steel pipe depends primarily on the wall thickness/diameter ratio and specified pipe tolerances. Due to improvements in production technology and increased cost-effectiveness, more than 80% of pipes are now typically welded.