Differences Between Seamless and Welded Steel Pipes

Photo by **SHOCKPhoto by Szoka Sebastian** from **Pexels**

To novices who are not familiar with construction materials, all pipes are the same.

However, there are different types, and seamless steel pipes and welded steel pipes are the most common ones.

Interestingly, these two bear so many similarities that a lot of folks cannot distinguish one from the other.

Therefore, in this article, we will look at the differences between a welded steel pipe and the seamless steel pipe.

With the information in this article, you will be able to identify which is which when you go for your next purchase.

Before we go into further details, here are some key differences:

	Seamless Pipe	Welded Pipe
Length	It is shorter because of difficulties during manufacturing	Comes in different lengths
Pipe Surface	Surfaces are rough because of the process of extrusion used in manufacturing	Surfaces are smoother
Economy	More Expensive	More economic
Application	High Pressure, high temperature, corrosive environment, and sensitive units	Low pressure, lower budgets, and reduced corrosive environment
Production Process	Complex with extended production and procurement period	Simpler with less production and procurement period
Shape	More round (ovality)	Poor ovality
Tests	Requires no testing before use	Requires testing before use
Strength	Can withstand extreme pressure	Pressure strength does not exceed 20% because of its welds
Diameter	Thicker	Thinner
Availability	This item is less available because of the availability of its raw materials	Readily available because of the availability of its raw materials
Size	Not more than 24 inches	Comes in any size
Molding Process	One rolling process is enough to manufacture it	Manufactured using steel strips as well as plates that after bending can be weld
Internal Surface Check	Impossible to check	Check is done before the production process
Welds	Does not have welds	LSAW, SSAW, DSAW, ERW
Ideal Application Field	High-pressure tools production, industrial boilers	Automobiles, electric, aerospace, construction industry

Seamless Steel Pipe

This item is manufactured using just one metal piece; hence, it is not joined at any part of its surface. This is why it is called seamless because it lacks any kind of welded joint or crease.

Seamless pipe is known for its perfect finishing which is one of the reasons why it is in high demand. They come in circular, square, or rectangular shapes. Furthermore, the pipes are hollow (tubular) which is necessary as they are used for carrying gas, slurries, liquid, and powders.

Its durability and strength are largely thanks to the fact that it cannot be welded and the absence of joints. This allows it to have an even-strength distribution across the entire structure. You can visit http://www.madehow.com/Volume-5/Steel-Pipe.html if you want to find out how this item is made.

Applications

The following are the application areas of this pipe:

Hydraulics
Chemical processing plants
Water purification plants
High pressure and temperature units
Manufacturing medical tools

Pros

No welds
Thick-walled and heavy
More round
Resistance to corrosion
Can withstand extreme pressure
Durability
Does not require testing for the weld integrity
Fusion metals are not used

Cons

Size constraint as it cannot be above 24 inches
Shorter length due to manufacturing difficulties
Wall thickness is inconsistent
Expensive
Rough surface as a result of the extrusion procedure

Welded Steel Pipe

Unlike seamless pipe, this has welded joints. This is where they derive their name from.

They are also more available compared to the seamless pipe as a result of the availability of their raw materials and lower cost of production.

Hence, it is widely used across the globe and finds application in several industries.

Types of welded steel pipes are ERW, LSAW, and SSAW pipes.

The ERW usually causes a bit of confusion for some folks as they easily think it is seamless steel because the weld is not visible as does not make use of fusion metals.