Seamless vs Welded Pipe: Which One Provides Sturdier Construction?

From this article, you'll learn how seamless vs welded pipes are made, and what are the main differences between them: from max length to variety in sizes
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Last updatedLast updated: June 20, 2022
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Welding is a science but it can seem a bit like magic. Metal is heated, connects to pieces of metal, and when done properly, the bond is tight, secure, and durable. Many people are wary of entering the world of welding, not only because of the skill involved but because of the many new terms to learn Trusted Source Welding Processes and Information about Different Types of Welds | GoWelding.org Information about the most commonly used welding processes in manufacturing, construction and just about anywhere! gowelding.org .

The average person has likely never given thought to how pipes are made, so all the information is new and can be overwhelming. This is especially true when discussing a seamless vs welded pipe. Pipes are pipes, right? Well not exactly. Turns out there are different ways of creating them. We’ll walk you through what the differences are between a seamless pip and a welded pipe so you can start off with a bit more knowledge on the subject.

How seamless pipes are made

Seamless vs Welded Pipe: Which One Provides Sturdier Construction?

If you’re even unsure about how a seamless pipe is made, just look to the name. Seamless pipes don’t have a seam on them. Instead, they are made from a solid piece of steel. This chunk of metal is then heated and stretched, and in order to craft its ultimate shape, is pulled over a form.

Seamless pipes can be made in different sizes but because of the energy used to create a larger pipe, the price greatly increases with their size. Seamless pipes are commonly used in construction, shipbuilding, and hydraulics.

Pros and cons

Overall, seamless pipes benefit from their non-welded joints which makes them able to withstand high pressure and heavy weights.

As mentioned previously, the large the seamless pipe, the more expensive they will be.

How welded pipes are made

Seamless vs Welded Pipe: Which One Provides Sturdier Construction?

Welded pipes start as one large sheet of steel. Then, they are placed on a bending machine and finally the two sides are welded together. As a result you will have a thin seam along one side of the circular pipe. You can even make your own welded pipes at home, although you want a decent machine, such as the DEKOPRO MMA Welder which has superior control during use.

Welded pipes are commonly used when you need large pieces, such as for transporting water or gas.

Pros and cons

Whatever length you need, you can create welded pipes. Furthermore, they are easier to craft and therefore can be delivered a lot quicker than seamless pipes. You can start with multiple welded pipes and then further weld them together to create a pipe of whatever length you need.

With more seams and welded points, there are more opportunities for corrosion. They are not always the best quality and rigorous testing must be performed in order to be certified for dangerous tasks.

Welded vs Seamless pipe: Main differences

If you’re still confused, please consult this table which outlines important differences between seamless and welded pipes.

Welded Seamless
Corrosion resistance Low Medium
Strength Medium High
Application Limited Full
Thickness Consistent Inconsistent
Shape Poor Even
Surface Smooth Rough
Value High Medium

Length

Seamless steel pipes have a fairly complex process. As a result, they cannot be very larger. Smaller seamless steel pipes are more affordable while larger ones can come with a very high price tag.

On the other hand, welded steel pipes can be better custom made to suit whatever lengths are needed. They are also more affordable, which is why they are more common.

Production

The production process for seamless steel pipes is fairly complex. In order to produce the pipes, the metal needs to be heated and stretched. Since seamless steel pipes are often custom-made according to length and diameter, the procurement time can be fairly lengthy.

Welded pipes are easier and faster to create. They are often pre-welded so you can simply choose the size of pipe that you need. You can even try various materials, like aluminum.

Tests

While you should always inquire about testing with any steel pipe, you have less to worry with seamless pipes. They do not require any testing because their steel starts from one piece. Therefore, there are no seams or possible weak points. If you use welded steel pipes, you must test them before use.

The more welded areas there are, the more risk there is of corrosion or weak spots.
The weld might not be as strong as needed and over time, they can even break at the welded parts. If you are using welded steel pipes to transport something dangerous, such as oil or gas, then rigorous testing is necessary.

Diameters

When we talk about the diameter, it means the width of the pipe surface. Seamless pipes can only be stretched so far so they will have a thicker diameter. As for welded pipes, they can be tempered to a much thinner appearance, resulting in a thinner diameter.

Availability

Both seamless and welded pipes are available but seamless ones need more lead time to be crafter. On the other hand, welded pipes are usually made in stock sizes so they are much easier to be found.

Internal surface

The internal surface, or inside of the metal pipes, is important to consider as it can hide a lot of imperfections. The internal surface of seamless pipes, however, can’t be checked because of how it is created.

Welded pipes can be checked and a test should be performed before the manufacturing process even takes place.

Field of use

Seamless vs Welded Pipe: Which One Provides Sturdier Construction?

Seamless pipes are commonly used in high-pressure environments. They are more stable and can be used for industrial boilers and other applications.

Welded pipes are used for a number of industries, including construction, electric, and automobile purposes.

Molding

Seamless pipes are manufactured once during the rolling process. As for welded pipes, they are created with stripes and plates that are then welded after being bent into the required shape.

Sizes

When you’re looking for size, seamless pipes are only available at a maximum of 24 inches. Welded pipes, however, don’t have any size restrictions. You can even use rather compact welders to quickly weld a smaller pipe.

Those wanting to try their hand and making different sizes of welded pipes should invest in a quality product like the ETOSHA MIG 140 Welder. It is portable, efficient, and safe to use. You can get pretty creative with it.

Final thoughts

We hope we’ve illuminated you on all the differences between seamless and welded pipes. It might seem a bit dry but pipes are all around us and sometimes it’s neat to understand just how everything is manufactured. Seamless pipes are made with one piece of metal that is stretched into shape. In contrast, welded pipes start as sheets of metal which are then shaped and welded together. When it comes to deciding between seamless vs welded pipe options, it all comes down to what your needs are. As for those new to welding, we suggest you practice, practice, practice Trusted Source Mastering the art of welding—it's all about proper technique One of the stupidest things I ever did as a parent was to buy my son a book about kyusho-waza (pressure point attack) written by master martial artist, George A. Dillman. I then became the recipient… www.thefabricator.com . You might be surprised at what creativity you can unleash.

References

1.
Welding Processes and Information about Different Types of Welds | GoWelding.org
Information about the most commonly used welding processes in manufacturing, construction and just about anywhere!
2.
Mastering the art of welding—it's all about proper technique
One of the stupidest things I ever did as a parent was to buy my son a book about kyusho-waza (pressure point attack) written by master martial artist, George A. Dillman. I then became the recipient…
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