Seamless vs Welded Pipe: Which Is Better?
Seamless vs Welded Pipe: Which Is Better?
Seamless vs Welded Pipe: Which Is Better?
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Which is better between seamless vs welded pipe?
Manufacturing
Strength
Corrosion resistance
Applications
Piping systems exist in almost any building or structure out there because of their innate usefulness. Whether theyre used to transport water or gas or for other structural purposes, youll find steel pipes on most construction sites. Pipe manufacturers do their best to meet the demands of the industry. They employ several methods to create different types of good-quality pipes. Because of this, companies find themselves wondering which is better between seamless vs welded pipe.
Seamless and welded pipes have many similarities. But as for pipe manufacturing processes, these two are commonly pitted against each other. Here, well talk about their differences in several factors to help you make a more informed decision on which one is better. Keep reading for more!
Manufacturing
The main difference between seamless pipes and welded pipes is in the way they were manufactured. To put it simply, seamless pipes are single pieces of metal with no seam or crease, or weld joint. Welded pipes are metal products that start as a strip that would be roll-formed and then welded to form a tube. Heres how they are both manufactured:
- Welded pipes: Welded pipes begin as skelps which are long ribbons of coiled steel. They would then be cut down to the desired dimensions until a flat rectangular sheet is left. These sheets would be fed to a rolling machine to curl the longer sides to each other and form a cylinder. For electric resistance welded (ERW) pipes, a high-frequency electric current would be passed between the edges to fuse them. No weld seam can be seen or felt after this process. For double submerged arc welding (DSAW) pipes, the weld bead would be seen but could be removed with additional processes. These pipes need to undergo heat treatment after manufacturing.
- Seamless pipes: A seamless pipe starts as a solid piece of steel called a billet. These billets are heated and then pierced with a mandrel to hollow them out. It will then be rolled and stretched until it meets the specifications that the customer ordered. Because they harden after manufacturing, some seamless pipes no longer need heat treatment. But some types still need heat treatment, so learn more about the type of pipe youre making first.
The welded pipe manufacturing process has improved a lot over the years, making them less prone to corrosion and seam failure. Both seamless and welded pipes end up as a reliable part of the construction process, but different techniques are used to create them.
Strength
Thanks to its lack of a weld joint, seamless pipes are known to be very durable. It lowers the chances for corrosion and eliminates any weak spots along the tube. Seamless pipes are also generally heavy and thick-walled, contributing to their overall strength. A welded pipes working pressure is 20% less than that of a seamless pipe, and they need to be thoroughly tested before use to ensure that they wont fail in the field. But because of the difficulty in manufacturing seamless pipes, their lengths are always shorter compared to welded pipes.
Welded pipes are typically lighter than seamless pipes. They also have tighter tolerances and are consistent in wall thickness, unlike seamless pipes which are not always consistent. Many innovations in the industry have also strengthened the weld joint more than what is historically known. Both are strong enough pipes just pick the right one that fits better with your project!
Corrosion Resistance
Most customers will be worried about possible impurities in the pipe. Thats why seamless pipes are sometimes favored over welded pipes because it has no joint that could cause weakness or corrosion. The weld joint is considered to lessen the corrosion resistance of the product and create more dimensional variation than needed. If you manufacture an ERW pipe, however, the weld joint shouldnt be an issue.
Applications
The two types of steel pipes being discussed here can be applied to many different industries based on their strengths and benefits. Seamless steel pipes have unique characteristics like being able to distribute weight evenly, withstand high temperatures and pressures, and others. This means they can be applied in industries such as chemical plants, hydraulics, nuclear power plants, water purification plants, medical equipment, oil and gas lines, and other similar applications.
Are you interested in learning more about Welded Steel Pipe? Contact us today to secure an expert consultation!
On the other hand, welded pipes are ordered because they are cost-effective and can be manufactured in different shapes and lengths. Some industries that capitalize on this are architecture, aerospace, food and beverage processing, automotive, construction, and many more.
Key Takeaway
The debate between seamless vs welded pipe is an ongoing one because everyones needs are unique and changes are made every day. The answer to the question of which is better depends on your needs. Before making a decision, try reading the article again to see which fits your project best.
Whether you opt for seamless or welded pipes, you would still need to get it from a reputable company, like Supreme Pipe! We have been delivering top-of-the-line steel pipes to satisfy our customers since . Check out the products that we offer, and inquire now if youre interested!
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Difference between seamless and welded pipe material
What is the difference between seamless and welded pipe?
Pipes form an integral part of systems that require transportation of various media across refineries or industrial process plants. The capacity of the component and the media they transport will depend on the material they are made from. Some of the common materials manufacturers use include PVC, stainless steel, alloy steel, carbon steel, nickel alloys, titanium alloys, copper nickel, monel, Inconel, Hastelloy, etc. The use of said materials is judicious, which means the cost factor is also taken into account while producing them. Basically, there are two kinds of pipe construction. First is the seamless kind, which contains no seam, and the circumference of the pipe will have no joints. So the surface of these pipes will be smoother and more even. The second type of construction is a welded type. Unlike the seamless kind, the welded type will have a seam that joins the pipe, which results in the formation of a seamline on its surface.
In short, the main difference between the construction of these two pipes is the inclusion of a seamline in a welded construction. Yet, there are some other parameters that separate both constructions including the pressure capacity and the price point. In terms of the pressure bearing property, the use of a seamless pipe enables higher pressure bearing ability. On average, the pressure borne by a seamless variety pipe is almost 20% higher than a conventionally welded one. This property makes it useful for a vendor to use a seamless type for a high pressure application. Although the use of a welded pipe is suited to high stress applications, its weld seam makes it vulnerable to failure, especially if the heat affected weld zone is prone to intergranular corrosion. If the pipe has been corroded by the sensitized grain boundary, the chances of a pipe bursting at the seamline are very high. This is an undesired effect, particularly in industries that transport across toxic material or bio-hazard media or even flammable compounds. In such instances, the vendor may choose to use a seamless pipe because they arent predisposed to intergranular corrosion and so, the chances of pipe burst occurring are drastically reduced.
Price difference between seamless and welded pipe
Another area that separates these pipe constructions is their price difference. The reason for the occurrence of the price difference is their manufacturing process. Since a welded pipe would make use of a metal plate, it is relatively economical to produce them. Moreover, the rate of production is also faster, which is also a factor that results in a product that is priced low. On the other hand, a seamless pipe is drawn through billets, and the manufacturing process is very laborious and consumes time. These factors bring the cost of the product higher as well. Furthermore, the pressure capacity of seamless pipes is higher than welded ones, and the surface is much smoother, with the chances of corrosion being reduced. A combination of all these factors makes the product an effective, yet costlier option in comparison to the welded pipe.
The seamless and welded pipe manufacturing process
As mentioned previously, welded pipes are manufactured using metallic sheets, with the wall thickness mentioned by the buyer. The length of the sheet prior to being welded is to be matched keeping both the inner and outer diameter of the pipe. These dimensions are to be given by the buyer during order placement. The welding method used, must be conducted in a manner that is set by the various standards. Usually, manufacturers, suppliers, and buyers abide by several of the ASTM standards that act as guidelines during production.
The production of seamless pipes makes use of heat treatments. The alloy is first heated, followed by molding with the use of a solid billet. The solid billet is what guides the alloy into a component that is shaped in the form of a cylinder. Once the alloy forms cylinders, they are rolled such that they get stretched and form hollows. During this process, the hollowed center of the cylinder is irregular shaped. To get an even, hollow center, a bullet-shaped piercer point is thrust through the core of the billet, simultaneously, as the cylinder is rolled. Following these processes, the pipes are put through additional machines that straighten them, while also eliminating deformities to create, better, smoother, and durable seamless pipes.
Seamless and welded pipe application
Since the main function of pipes is to ferry across materials, the application or the end-use of the product will be based on several factors including cost, strength, type of media being used in the application, the resistance of the alloy to corrosion in addition to the temperature and pressure requirements. Industries such as pharmaceutical, building & construction, food processing, beverage industry, nuclear & power generation, etc, make use of pipes to transport across their products. However, the industry that makes the most of these components is the petrochemical and natural gas industry.
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