Difference Between ERW Steel Tube and Seamless Tube

By adminAug 31,2017

Quick Inquiry


Nowadays, with the quick construction of society and rapid development of technology, more and more different kinds of steel tubes are created, such as welded steel tubes, seamless steel tubes, ERW steel tube and so on, and more steel tubes are needed. In the competitive market of steel tube, seamless tube and welded steel tube are well-sold.

There are a few aspects of differences between ERW steel tube and seamless steel tube. ERW tube, which is short for electric resistance welding, is used in delivery of liquid, such as fuel, gas and so on, regardless the requirement of pressure, which plays an important role in the conveying tube all over the world, while seamless tube is a kind of steel tube shaping square and rectangle and having no seam around with hollow cross-sections, which is used in conveying liquid but also making structural members and machine parts, due to its surprisingly high anti-bending and anti-torque strength and impossible lightness. All in all, ERW tube and seamless steel tube is quite different in use.

Let’s have a glance on those differences between seamless and ERW that can make huge differences for your application and economics of operation.

#1 Raw material


Seamless tubes are manufactured out of round steel billets and ERW tubes are made out of hot rolled coils. Although both the raw materials are entirely different, it should be noted that the quality of end product – tubes, entirely depends upon both factors – quality control during the manufacturing process and the initial condition and quality of raw materials.

#2 Manufacturing process


Round steel billets are heated and pushed over the piercing rod until the hollow shape is achieved. Subsequently, their length and thickness are controlled through extrusion techniques. It is a completely different story in the production of ERW tubes. The coils are bent axially and the converging edges are welded throughout their length by electric resistance welding.

#3 Welding process


As seamless tubes are extruded, they do not have any sort of joint either in axial or radial direction. On the other hand, ERW tubes are made out by bending coils along their central axis and hence they are welded throughout their length.

#4 Size


Seamless stainless steel tubes are completely finished in their assembly line and are fabricated up to 26 inches of outer diameter. On the other hand, even the most advanced Steel Company deploying ERW techniques, go only up to 24 inches of outer diameter.

#5 Applications


  • Generally, seamless tubes are used for applications that demand high pressure and ERW tubes are utilized for the services of low and medium pressure areas.
  • Also, considering the inherent safety features of seamless tubes, they are widely used in applications of oil and gas, refineries, and other chemical industries, where personnel and plant safety needs to be ensured through zero leakage policies. That being said, well manufactured ERW tubes under strict quality control can also be put into similar services other than the routine ones like water transportation, scaffolding, and fencing.

#6 Finish It is a known fact that the internal finish of ERW tubes is always controlled through good quality control techniques, and hence they are always superior to seamless tubes.


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