Factors Affecting the Pulling Force of Stainless Steel Tube

There are many factors that affect the pulling force of stainless steel pipe during the drawing process. According to the results of many scientific workers and actual production operators, some of them are conducive to the drawing process. While other factors just increase the difficulty of stretching the contrary. Pull out the process of drawing and stretching the performance of metal, heat treatment, the deformation of each pass stretch speed. Dry pipe between the mold and the friction, lubrication, geometry and mold shape are closely related.

Barren tube material, chemical composition and organizational structure is different, then its mechanical properties are also different, a direct impact on the size of the pulling force. Such as stretching 20 carbon steel and 36Mn2Si waste management of pipe pulling force must be much larger than the 120 steel, mainly due to the mechanical properties of two different materials due to the insulation. Dry pipe in the drawing process to produce work hardening phenomenon, the deformation resistance increases the plasticity decreases, the difference continues to pull the drawing force continues to increase, prompting shortage of stress within the pipe is easy to produce cracks or rip defects, uneven wall thickness of the barren. The tube is not sensitive, in order to eliminate the internal stress of waste tube after stretching, should be promptly annealed. Stretching die shape, the main extension is the shape of the outer mold (ie, work with the width of the width and extension angle size). The effect of working width on pulling force increases with the decrease of shortage tube. Because of the small amount of deformation, the shortage pipe was forced into the work zone under the compressive stress of forced deformation, and the outer friction between the shortage pipe and the work belt increased the drawing power. If the angle of extension is too large, the deformation of the tube will increase and the deformation stress will increase accordingly, so that the pulling force will increase. And drawing angle over the general assembly to make lubrication conditions deteriorate, causing the friction coefficient will increase the pulling force increases. The difference angle is too small. Under the same deformation condition, the contact area increases when the angle is larger, so that the friction force increases, so that the pulling force increases. Therefore, the reasonable design of the drawing angle is very much as long as the factors generally take the angle of 12 ~ 13 ° is more appropriate.

Drawing die surface roughness and hardness of the drawing force is very obvious, the mold should have sufficient hardness and good surface finish, will make the friction between the contact surface becomes smaller, so that drawing force reduced. On the contrary, poor mold does not have enough hardness and surface finish, will inevitably lead to increased friction. Promote pulling force increases. Therefore, the preparation of the mold is a very important task, the use of high-quality mold is one of the main conditions for access to high-quality steel.

Pre-pull waste management (ie, pipe) preparation; such as pickling, washing, lubrication and other process quality is extremely important. It is directly related to the friction during extension. A good preparation process greatly reduces the friction of the ejection. The pull-out force is correspondingly reduced. This creates a favorable condition for increasing the amount of extension deformation. Drawing speed on the pulling force is not obvious, according to the former soviet scientists and practical experience shows that; stretching speed from when the extension to pull the process of drawing a slight increase of about 4 ~ 8%, poor speed continue to improve, pulling force little change, a slight increase, the increase is relatively flat. This shows that the relationship between speed and stretching are not entirely possible to increase the speed of drawing to increase production.

In summary, the factors that affect the pulling force is more. Due to the different operation modes in the production process, the pulling force of waste pipe may be completely different. In order to improve drawing conditions and reduce pulling force, the selection of raw materials (that is, waste pipe should have good material and good mechanical properties, etc.) (Such as acid west, flushing, lubrication, heat treatment and other process quality), the distribution of deformation and the determination of stretch passes are all the necessary conditions for the production of high quality steel pipe.

A worker from a steel pipe company, which is located in China.