What are the production processes of seamless steel pipes? Relying on its characteristics and strengths, seamless steel pipes are increasingly used in fields such as the installation of large equipment and the hydraulic machinery industry. Compared with the common steel pipes (welded pipes) before, seamless steel pipes adopt a series of high-tech manufacturing technologies, which contribute to the excellent quality of steel pipes. So, what are the production processes of seamless steel pipes? Let’s learn about it together today. The production process of general seamless steel pipes can be divided into two types: cold drawing and hot rolling. Hot rolling, as the name suggests, has a high temperature, so the deformation resistance is small, and large deformation can be achieved. Take the rolling of steel plates as an example. Generally, the thickness of the continuous casting billet is about 230mm, and after rough rolling and finish rolling, the final thickness is 1~20mm. At the same time, due to the small width-to-thickness ratio of the steel plate, the dimensional accuracy requirements are relatively low, and plate shape problems are not prone to occur. The main focus is to control the crown.
The production process of cold-rolled seamless steel pipes is generally more complicated than hot-rolling. The tube blanks must first undergo three continuous rolls. After extrusion, a sizing test must be performed. If there are no cracks on the surface, the round tubes must be cut by a cutting machine. Cut into blanks about one meter in length.
The hot rolling process sequence is as follows: round tube blank → heating → piercing → three-roll cross rolling, continuous rolling or extrusion → tube removal → sizing (or diameter reduction) → cooling → straightening → hydraulic test (or flaw detection) → marking →Inbound seamless steel pipes are made from steel ingots or solid tube blanks that are perforated into capillary tubes, and then hot rolled, cold rolled or cold drawn. The specifications of seamless steel pipes are expressed in terms of outer diameter * wall thickness in millimeters.
Seamless steel pipes are divided into two categories: hot-rolled and cold-rolled (dial) seamless steel pipes. Hot-rolled seamless steel pipes are divided into general steel pipes, low and medium-pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes, and other steel pipes. In addition to general steel pipes, low and medium-pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, cold-rolled (rolled) seamless steel pipes also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, Stainless thin-walled steel pipes, special-shaped steel pipes.
The outer diameter of hot-rolled seamless steel pipes is generally greater than 32mm and the wall thickness is 2.5-200mm. The outer diameter of cold-rolled seamless steel pipes can be up to 6mm and the wall thickness can be up to 0.25mm. The outer diameter of thin-walled pipes can be up to 5mm and the wall thickness is less than 0.25mm. Rolling has higher dimensional accuracy than hot rolling.
General seamless steel pipes are made of hot-rolled or cold-rolled high-quality carbon structural steels such as 10, 20, 30, 35, 45, 16Mn, 5MnV and other low-alloy structural steels, or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other composite steels. Seamless pipes made of 10 and 20-grade low-carbon steel are mainly used for fluid transportation pipelines.
Seamless tubes made of medium carbon steel such as 45 and 40Cr are used to manufacture mechanical parts, such as stressed parts of automobiles and tractors. Generally, seamless steel pipes must ensure strength and flattening tests. Hot-rolled steel pipes are delivered in a hot-rolled or heat-treated state; cold-rolled steel pipes are delivered in a hot or heat-treated state.
Post time: Feb-01-2024