Identification Method of Seamless Steel Pipe and Welded Steel Pipe


Seamless steel pipe (SMLS) is formed by drawing a solid billet over a piercing rod to create the hollow shell, without welding or seam.It is suitable for bending and flanging. The most advantage is increasing the ability of withstanding higher pressure.Seamless steel pipe can be cut,threaded or grooved.And the coating method includes black/ red lacquer,varnish painting,hot dip galvanization,etc.

Welded steel pipe:

Welded steel pipe (steel pipe manufactured with a weld) is a tubular product made out of flat plates, known as skelp, that are formed, bent and prepared for welding.

There are the difference between welded steel pipe and seamless steel pipe:

Different appearances: welded steel pipe has welding line on the inner wall of welded pipe, but seamless steel pipe does not have.

Pressure is different: welded steel pipe has about 10 MPa, while seamless steel pipe has higher pressure.

Advantages of Welded Steel Pipe

Welded pipe is made by cold forming flat strip, sheet or plates into a round or circular shape by a roller or plate bending machine. The pipe is then welded with or without filler material using a high energy source. Welded pipes can be produced in large sizes without any size restriction. Welded pipes are normally used for transportation of water, oil or gases in large quantities.

Welded steel pipes are always available in plenty because of their lower production cost and raw materials availability. It is, therefore, one of the most widely used metals in the world. Its application in different industries and the manufacture of numerous products. Examples of ASTM or API 5L welded steel pipes include SSAW pipe, ERW steel pipe, and LSAW pipe.