Difference between ERW Stainless and Seamless Steel Pipes

Stainless steel products, considering its excellent properties, are widely applied in various industries. What you are going to learn today, are seamless stainless steel pipes and ERW stainless steel pipes, or electric resistance welding pipe, which are two essential parts of stainless steel products. However, there are many differences between the two kinds. All these will be uncovered in the following paragraphs.

Seamless and ERW stainless steel pipes are both demanding in construction, and all kinds of forms, shapes, and sizes are required.

Usually, seamless pipes are made of billet, a kind of solid round steel, by pushing and heating. After that, they become the shape of a hollow tube. ERW pipes, however, are made of another material, HR coils, though heating and pushing are also required in the manufacture.

Difference between ERW Stainless Steel Pipe and Seamless Stainless Steel Pipe:

Whether there is a cross-section in the pipe or not makes a difference between ERW and seamless pipes, due to there different manufacturing process. While manufacturing ERW pipes, the raw material will be rolled first, and then welded longitudinally throughout. In the manufacture of seamless pipes, however, the metal will be extruded into the desired length.

ERW pipes are usually made from coil or strip, which will be welded longitudinally. Firstly, they are cold-formed as a ribbon of steel, then pulled through a series of rollers, and finally turn into tubes before being fused through an electric charge. They can range in sizes up to 24” OD and are favoured in low to medium pressure applications in most cases. The most common sizes of them, however, are 2 3/8 inches to 24 inches OD, with various lengths, longest reaching 100 feet. The finished products of ERW pipes can either be further sent for coating or stay bare. This depends on the customers’ specified requirements.

Seamless stainless steel pipes, though, make a difference from the beginning. They are made of billet, having sizes of wall thickness available to range from 1/8 to 26 inches OD specifically. Finished two dimensions is another feature of these pipes. As a result, they are not available for joint or welding. And in most cases, they are applied for high-pressure constructions.

How to Identify ERW Stainless and Seamless Steel Pipes?

A steep itself tells you whether it is Electric Resistance Welded (ERW) or seamless steel pipe. How so? You can identify ERX stainless or seamless steel pipes from the stencil printed on the side of the pipe.

If the pipe is ASTM A53,

  • Type S denotes it is seamless.
  • Type F denotes it is furnace but welded.
  • Type E denotes it is electrical to resist welded.

This is the easiest way to recognize whether the pipe is ERW or seamless.

What Technologies Are Used to Manufacture ERW Stainless and Seamless Steel Pipes?

The “CPE technology” is used to manufacture ERW and seamless pipe. The seamless pipe is done to the wall, and dimensional thickness specifications in sizes range from 1/8″ to 26″ OD. These are appropriate for high-pressure applications, for example, Oil & Gas Transportation, Refineries, Hydrocarbon Industries, Air & Hydraulic Cylinders, Oil & Gas Exploration & Drilling, Boilers, etc. 

On the other hand, ERW pipes are welded longitudinally. These are manufactured from oil or strip, and they can be manufactured up to 24″ OD. Basically, ERW pipes are assembled by the ribbon of steel. Here the steel is pulled by a group of pliers and then shaped into a tube. This is mostly utilized for non-moderate pressure applications, such as transport of water or oil.

What Raw Material Needed for Manufacturing ERW Stainless and Seamless Steel Pipes?

Generally, seamless steel pipes are made from solid round steel called “billet”. Firstly, it is heated and then pulled or pushed over a form. This is done until the steel get a hollow tube shape. You can gets billet both from native suppliers, or you can import from abroad.

JSW, JSPL and Kalyani are the key native suppliers. Besides, the well-known mills from Canada, Europe, China, and Fae East Countries provides steel round billets. However, HR coils are needed to manufacture ERW stainless steel pipes. And, Essar, SAIL, Lloyds, JSW, etc. are the major native supplier of HR coils.

In short, seamless steel pipes have very few disadvantages. But there is one crucial defect that comes along with welding in tubing across the length of there duration. After all, before making decisions, you must learn more about the products that you are going to apply in your construction so that you can foresee the impact it will bring along to your work.