The difference between welded steel pipe and seamless steel pipe

Seamless 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.

API 5L ERW steel pipes

API 5L ERW steel pipes

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.

Q345B 16Mn seamless steel pipes

Q345B 16Mn seamless steel pipes

Different processing technologies:

Seamless pipe is made of high quality carbon steel or alloy steel. The processing technology of seamless pipe can be divided into two main methods: cold drawing and hot rolling, while welded pipe is usually made of rolled steel plate welded by butt seam or spiral seam.

Different usages:

Seamless pipes are mainly used as pipes or structural parts for conveying fluids, mainly used in machinery industry, while welded pipes are mainly used in construction industry, conveying low-pressure fluids such as water, gas, compressed air, etc. However, seamless steel pipes are used in pressure pipes.

Prices are different:

Because of the complex manufacturing process of seamless steel tube, the price is more expensive than that of welded steel tube. Welded steel tube is mainly made of steel plate (steel strip) through secondary welding, which is cheaper and widely used.

Our products such as seamless steel pipes are widely used in low and medium pressure boilers, petroleum casing pipes, ships, fluid conveyance, petroleum cracking, chemical fertilizer equipment, structures, and hollow pumping rods. We can produce seamless steel pipe according to the standards such as GB, ASTM, API 5L, API 5CT, DIN and JIS. Our products have been sold around China and exported to over dozens of countries and regions in the world, such as Southeast Asia, the Middle East, Europe and America etc., enjoying the very high prestige in the domestic and foreign markets. If you recently have purchase plans about our product, please feel free to contact