The characteristics of high-precision cold-drawn tubes produced by cold-drawn methods

- Feb 18, 2021-

High-precision cold-drawn pipe refers to a precision steel pipe with strict internal and external dimensional accuracy (tolerance range), good internal and external surface finish, roundness, and straightness, and uniform wall thickness. After a little honing, the product can be directly used as a cylinder tube for hydraulic and pneumatic cylinders. The traditional production process of hydraulic and pneumatic cylinder body tubes is to use hot-rolled seamless steel pipes, using a combined cutting process of boring one-by-one rolling. During the production process, a large amount of metal is cut into chips and is wasted, and it is also consumed. A lot of electricity. With the development of my country's industrial technology, hydraulic cylinder technology has been widely used. According to incomplete statistics, the country needs about 3.8 million meters of hydraulic cylinder bodies of various specifications every year. It is difficult to adapt to the production of hydraulic cylinder bodies using old technology. The needs of production development.

Compared with the traditional cutting process, the production of high-precision cold-drawn pipes (hydraulic cylinder blocks) using new technology and cold-drawn methods has the following characteristics:

(1) High production efficiency: It takes 154 hours to produce a cylinder with an inner diameter of 420 mm and a length of 12 meters by the traditional method, and it takes only 4 minutes to produce by the cold drawing method.

(2) High authenticity rate: Since the rolling head of the boring hole also plays a guiding role, during the cutting process, the rough tube deflection due to its own weight causes the rolling head and the boring tool to deviate, resulting in waste products. The rate of authenticity can only reach about 60%, and the rate of authenticity can reach more than 95% when produced by cold drawing.

(3) High metal utilization rate: The metal utilization rate is only 50-70% when the cylinder body is manufactured by the traditional boring method. When using the drawing method to produce, not only the metal is not cut into iron powder, but 30% extension can be obtained, and the metal utilization rate can reach 95%.

(4) It can improve the mechanical properties of the finished pipe metal: it is produced by drawing method, so that the blank gets plastic deformation of more than 30%, and the strength limit of the finished pipe metal is greatly improved due to work hardening. Generally, the inner strength limit of the finished pipe is increased by 60%. High-precision cold-drawn pipes are made of seamless hot-rolled steel pipes and longitudinally welded pipes as blanks. After chemical treatment, they are drawn on a special cold-drawn machine using a mold designed with special deformation principles to produce high-precision pipes. The dimensional accuracy is H10~H8, the straightness is 0.35~0.5mm/m, and the surface roughness is Ra1.6~0.4.

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