What equipment is used in the production of seamless steel pipes?

The production line includes fully automated hot-rolled seamless steel pipe lines, hydraulic cold drawing machines, pipe straightening machines, precision rolling straighteners, coil straightening and cutting machines, among others. There are numerous types of straightening and drawing machines used in production!

Let's dive into the details:

Piercing Machine:

This machine transforms round billets into hollow thick-walled tubes. The rollers are set at an angle to the rolling line, which has recently increased from 6°-12° to 13°-17°, enhancing the piercing speed. For seamless steel pipes with diameters above 250 mm, a second piercing step is used to thin the billet walls. Innovations like active rotary guide piercing, rear thrust piercing, axial discharge, and cyclic top welding have strengthened the process and improved billet quality.

Automatic Pipe Rolling Machine:

Thick-walled billets are rolled into thin-walled rough pipes in 2-3 passes to reach the final wall thickness, achieving an elongation ratio of 1.8-2.2. Since the 1970s, improvements such as single-groove rolls, tandem rolling with dual stands, double-groove tracking, and spherical mandrels have boosted production efficiency and mechanized the process.

Sizing Machine:

This machine, similar to the piercing machine, is used to eliminate defects and ovality in rough pipes and to ensure uniform wall thickness. The introduction of three-roll sizing machines has increased the efficiency and deformation capacity.

Sizing Mill:

With 3 to 12 stands and a reducing mill with 12 to 24 stands, this machine achieves a reduction rate of 3-28%. The tension reducing mill, developed in the 1950s, uses tension to control wall thickness during the rolling process. Modern versions, typically three-roll with 18 to 28 stands, achieve up to 80% reduction and a wall reduction rate of 44%, with output speeds of 18 mm per second. Issues with end thickening can be resolved with advanced control techniques.

Automatic Pipe Rolling Unit:

This unit comes in various series for producing seamless steel pipes with diameters ranging from 17 to 426 mm. Major deformation occurs at the piercing stage, allowing flexibility in production. Continuous pipe rolling technology advancements have made units under 140 mm obsolete.