What Is Difference Between Seamless And ERW Pipe?

Raw Material Required For Manufacturing Seamless & ERW Pipe

Seamless(SMLS)Pipes areextruded and drawn from a solid round steel billet that is heated and pushed or pulled over a die until the steel billet is formed into a hollow tube. To manufacture ERW(Electric Resistance Welded) Pipes, hot rolled coils are required.

Difference Between Seamless And ERW Pipe

There are no welding or joints on seamless pipe. The finished dimension sizes of seamless pipe is from 1/8 inch to 26 inch OD.

ERW pipe is welded longitudinally, manufactured from steel strip or steel coil and can be manufactured up to 24 inch OD.

Price Difference Between ERW And Seamless Pipe

Compare to ERW pipes, seamless pipes have a longer manufacturing process, with multiple operations, so the cost of seamless pipes is always higher than ERW pipe. ERW pipes are made of cold formed sheets and joined together by high frequency welding, which is a relatively simple process.Considering seamless pipe’s higher range of safety measure, it’s expensive thanERW pipe.

Manufacturing Process Difference Between Seamless And ERW Pipe

ERW pipe may be produced by cold forming a steel sheet into the shape of a cylinder. After being cold formed, an electric current is then passed between the two edges of the steel. The electric current heats the cold formed steel sheet to a point such that the edges are forced synchronically to form a bond. There is no need to use welding filler material during this welding process.

Unlike ERW pipe, the manufacturing procedure of seamless pipe is longer and more intensive. Raw steel is first heated and cast into solid billets, which mold the raw steel alloy into a cylinderical shape. Upon achieving the step, the raw steel pipe is then rolled until a stretched and hollowed product is created. This newly created product has a center that is irregularly shaped. To get a more even surface and uniform shaped hollow tube, a bullet shaped piercer point is rammed through the center of the billet even as the billet is being rolled.

Welding Process Difference Between Seamless And ERW Pipe

Since seamless pipes are extruded, they do not have any kind of joints in the axial or radial direction. ERW tubes, on the other hand, are made by bending coils along their central axis, so they are welded throughout their length.

Application Difference Between Seamless And ERW Pipe

Typically, seamless pipes are used for applications requiring high pressure and ERW pipes are used for service in low and medium pressure areas.