Stainless steel welded pipe and stainless steel seamless pipe are two common types of pipes used in various industries. The main difference between these two types of pipes is the manufacturing process and their physical characteristics.

Stainless steel welded pipe is manufactured by welding stainless steel sheets or plates together to form a tube. The welding can be done using various methods such as electric resistance welding (ERW), fusion welding, or laser welding. Welded pipes have a welded seam that runs along the length of the pipe, and the thickness of the wall is consistent throughout the pipe.

On the other hand, stainless steel seamless pipe is manufactured by piercing a solid stainless steel billet to form a hollow tube. This process does not involve any welding, and the resulting pipe has no welded seams. Seamless pipes have a uniform thickness throughout the pipe, which makes them stronger and more durable than welded pipes.

In terms of physical characteristics, seamless pipes have a smoother interior surface than welded pipes, which makes them better for applications where fluid or gas flows through the pipe. Welded pipes, on the other hand, are more cost-effective than seamless pipes and are often used in applications where the pipe does not need to withstand high pressure or temperature.

In summary, Overall, while both types of pipes are made of stainless steel and have similar properties, the manufacturing process and the resulting characteristics of the pipe make them more suitable for different applications.