The Difference Between Seamless Pipe And Welded Pipe

Sep 19


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lvy lee12

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Steel pipe is a kind of hollow long steel, which is used as a pipe for conveying fluids, such as petroleum, natural gas, water, gas, steam, etc. In addition, when the bending and torsional strength are the same, the weight is light, so it is also widely used. Used in the manufacture of mechanical parts and engineering structures. Also used to produce a variety of conventional weapons, barrels, shells and so on.


The seamless steel pipe is made of a single piece of metal with no seams on the surface. Seamless steel pipe is mainly used as petroleum geological drilling pipe,The Difference Between Seamless Pipe And Welded Pipe Articles cracking pipe for petrochemical industry, boiler pipe, bearing pipe and high-precision structural steel pipe for automobile, tractor and aviation. (one time molding)

Welded pipe is also called welded steel pipe. It is a steel pipe made by welding and forming a steel plate or strip steel. It is usually 6 meters long. According to the weld seam - straight seam welded pipe(ERW,LSAW), spiral welded pipe(SSAW). (after secondary processing)

In appearance, the seamless pipe and the welded steel pipe have a weld bead on the inner wall of the welded pipe, and are seamless.

The seamless pipe pressure is higher, the welded pipe is generally about 10 MPa, and now the welded pipe has been seamlessly processed. The seamless tube is formed once in the rolling. Welded steel pipes need to be welded after rolling, and generally have spiral welding and straight welding.

Performance seamless pipe is better, of course, the price is also high - some. The seamless steel pipe is formed by perforating a steel ingot or a solid tube blank, and then hot rolled, cold rolled or cold drawn. The seamless tube has a hollow section and is used in a large amount as a conduit for transporting fluid. A welded pipe is a steel pipe which is welded and deformed into a round shape by a steel strip or a steel plate and has a joint on the surface. The blank used for the welded pipe is steel plate or strip.

Identification method: Look inside the pipe, because the outside will be processed, the welded pipe has a gap inside, some can be seen, some are processed, it is not easy to see, you can touch slowly by hand, or look at the specifications, The welded pipes are relatively thin. The welded pipes are made directly from the machine with stainless steel strips (rolled up), and the seamless is pierced with round steel or tube blanks.

Ordinary steel pipes, such as tap water pipes, are usually welded by bending the flat plates. You can find a weld on the top; the coarser diameter is usually a spiral weld. The seamless steel pipe is generally formed by laminating molten steel in a molten state through a ring slit and then being subjected to a stretching process, so that there is no weld. In terms of performance, especially the pressure bearing capacity is greatly improved compared with ordinary steel pipes, so it is often used on high-voltage equipment. Such as the piping connection of hydraulic equipment. The weld seam
of ordinary steel pipe is its weak link, and the weld quality is also the main factor affecting its overall performance. People who have lived in the north generally have experienced the experience that the water pipes or heating pipes are frozen in the winter. The places where the explosions are usually welded. The welded pipe is not a seamless steel pipe.

The essential difference between the two is that the welded pipe is generally lower in strength than the seamless steel pipe. In addition, the welded pipe has many specifications and is inexpensive. Seamless steel pipes are generally used in the case of high use conditions, such as high temperature and pressure, and have certain requirements for stress corrosion, and seamless steel pipes are used.