20 Years of Experience in Seamless Steel Tube Production

Manufacturing Method of Cold Drawn Seamless Tube

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The tube manufacturing process has changed significantly, especially during the first five years of the 21st century, a period in which machines with higher productivity capabilities were developed. 

Thus, the machinery used to manufacture pipes. It allows you to have the most advanced technology at hand, and with a low price. If you want to know more about this type of machine,  continue reading the article that we have prepared for you in our website of ShengDingYuan.

Until before the 20th century, the only technique used was that of lamination, which involved lengthy processes from when laminated sheets were joined into circular cross-sections with rollers until they were welded by means of what was called a seam in a forging process. If we see them from the perspective of the modern machinery that man has invented, we can conclude that at present it is really archaic processes. Fortunately, the processes are increasingly modern and allow for the creation of pipes of greater quality and resistance.

Currently, it is possible to manufacture both welded and seamless tubes. One of the most widely used processes without welding is the one that melts the material, at the same time that it is introduced at the end of a container with the circular shape, and then it is forced under high degrees of pressure through a nuance that pierces it and turns it into a tube that comes out through a hole, already with the approximate dimensions.

The two main tube manufacturing processes

Although there are experts who classify the different tube manufacturing processes into three, we must say that the most correct thing is to differentiate them into two:

●Seamless. That is to say without welding, also called by stretching of steel.

●With sewing. This is where some divide this type in two, differentiating the longitudinal seam and the helical seam, since the manufacturing process between the two has differences.

For practical purposes, we will only divide them in two, so that you know why the machinery used for the manufacture of pipe plays an important role, depending on the type of pipe you want to manufacture.

Seamless tube manufacturing

This manufacturing process is one of the most common. Part of a cylindrical ingot that is heated in a furnace before the extrusion process, that is, its introduction by a cylindrical die and its drilling by means of a perforator. It is, without a doubt, an excellent manufacturing method for thick tubes that are difficult to bend and that must withstand pressure in any direction and, in addition, must be resistant to corrosion.

Despite the fact that the extrusion is the most common seamless tube manufacturing process, we must say that there are other methods, such as pistol drilling, which provides a much more uniform outer diameter and a much more concentric inner diameter. In both processes, the use of machinery used to manufacture pipes plays an essential role and, therefore, you need to choose the one that best suits the needs of your industry and the type of pipe you need to manufacture for your customers.


Seamless tubes are usually classified into two types

1.Cold Drawn Seamless Mechanical Tubes (Cold Drawn Seamless or CDS)

Generally, this type of pipe is made with 1018 carbon steel and also with 1026 steel, two of the most common types of steel that exist, but which have many properties that make them ideal for the cold drawing process, which increases the physical properties of the tube, reducing machining time.

We must say that this type of seamless tube has a much more uniform internal and external diameter, with precise tolerance, which makes it a type of pipe with a good relationship between strength and weight. This feature allows it to be used more easily for machining processes.

It is a type of tube that has advantages such as:

●A better-finished surface

●High resistance to weight

●High elastic limit

●Great dimensional precision and micro structure uniformity.

●Ease of mechanization

●Tight tolerances, resulting in shorter post-machining time

2.Hot Finished Seamless Mechanical Tubes (HFS)

They are typically made of 1026 carbon steel, commonly used in the automotive, construction, and appliance industries. This type of pipe is generally made from a rotating bar that is drilled to create a hollow tube. The use of specialized machinery to manufacture this type of pipe is essential, which is why many experts choose to buy used machinery for the manufacture of pipes, which plays an essential role. It is used as a more cost-effective alternative to hot-finished seamless mechanical tubing, resulting in a wider tolerance range in OD and ID.

Among the main advantages that we can highlight of this type of pipe we find:

●Good value for money at high wall thicknesses

●Ease of machining

●Supports most processing techniques

●Availability in a wide range of measures


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