Seamless Pipe vs Welded Pipe

In high-pressure applications such as refineries, hydrocarbon industries, oil and gas infrastructure, engineers are tasked with ensuring that every component used is capable of withstanding the forces under which it is expected to operate. 

In these instances, seamless pipe will always be chosen over its welded counterpart. But, as a more costly product with a longer lead time, surely there must be some wiggle room here?  

Why choose seamless pipe?

The difference between seamless and welded pipe is exactly what the name denotes. 

A welded pipe is formed from a flat sheet of metal which is rolled into the required size and then welded at the seam. In some cases, the weld is completed using a high-frequency electrical current which results in a strong yet almost invisible seam. 

A seamless pipe, on the other hand, starts its life as a solid bar which is formed into a steel cylinder or billet. While there are several ways to cast a seamless pipe, the basic premise is that these solid cylinders are heated up and cast over a piercing rod until the desired thickness and length is required. 

The difference in the crafting of these options dictates the amount of pressure that each can withstand, and that is the point of focus for many industries, as noted above. 

One doesn’t need to be an engineer to understand that given the right conditions, a pipe is going to fail at its weakest point, and where there’s a weld, there’s a weakness. A seamless pipe is therefore chosen to carry liquids and is used in gas lines where there is simply no margin for error. 

As a superior product, a seamless pipe can replace a welded pipe, but the reverse is not true, even when choosing a pipe with a thicker wall. 

Do you have questions on seamless pipe or other metal fabrication requirements? If so, we’d like to encourage you to contact the Steelmor team and have a chat with the professionals.