What Is Seamless Steel Pipe?

Seamless steel pipe is made of a single metal with no joints on the surface, called seamless steel pipe. According to the production method, hot-rolled tubes, cold-rolled tubes, cold drawn tubes, extruded tubes, jacking tubes, etc. are seamlessly divided. Seamless steel tubes are divided into two types: round and irregular according to the cross-sectional shape. Special-shaped tubes have various complex shapes such as square, ellipse, triangle, hexagon, melon, star, and fin. The maximum diameter is 650mm and the minimum diameter is 0.3mm. According to different uses, there are thick-walled tubes and thin-walled tubes. Seamless steel tubes are mainly used for high-precision structural steel tubes such as petroleum geological drilling tubes, petrochemical cracking tubes, boiler tubes, bearing tubes, automobiles, tractors, and aviation.

Seamless steel tubes are widely used. The universal seamless steel pipe is rolled from ordinary carbon structural steel, low alloy structural steel or alloy structural steel with the highest yield strength, and is mainly used as a pipeline or structural part for conveying fluid.

Seamless steel pipe is a kind of hollow section steel pipe, which is widely used as a pipeline for transporting fluids, such as pipelines for transporting oil, natural gas, natural gas, water, and certain solid materials. Compared with solid steel such as round steel, the steel pipe has a lighter weight under the same bending and torsional strength and is economical section steel.

Seamless steel tubes have no longitudinal welds. The manufacture of seamless steel tubes requires a mechanism to press the holes into the billet.

Rotary piercing and rolling are currently the most commonly used methods for producing seamless steel tubes. The process starts with a treated round steel rod, which is heated, perforated, and processed. To form a hollow billet, the bar is made to flow around the perforation point. When the billet roll is stretched, a mandrel or plug is used to support the inside of the pipe. The sizing of the steel pipe is achieved by additional rolling on the outer diameter.

The seamless steel pipe has no welding seam, so its working pressure is 20% higher than the welded steel pipe of the same material and size. Welded and stretched steel pipes can also potentially involve visible seams by the end-user.

Another advantage of a seamless steel pipe is that it can provide superior corrosion resistance because it has almost no potential impurities. The use of seamless steel tubes can avoid potential defects and differences in ductility associated with the welded area in the welded pipe. Unlike welded tubes, seamless tubes do not require welding integrity testing.

Therefore, seamless steel tubes are usually more suitable for critical applications.

The above information is provided by ASTM seamless steel pipe manufacturer.