Drawing

Tube drawing is a process to size a tube by shrinking a large diameter tube into a smaller one, by drawing the tube through a die. It is commonly used for the production of high precision tubes.

There are four kinds of drawing commonly used:

    ■ Fixed plug drawing

    ■ Floating plug drawing

    ■ Mandrel drawing

    ■ Hollow sinking

The fixed plug drawing is suitable for the fabrication of thick-walled tubes. However, it is difficult to draw thin and long tubes due to the diameter limitation and elastic deformation of the connecting mandrel. Therefore, the fabrication of fine tubes is generally carried out by the floating plug drawing or the mandrel drawing.

In the mandrel drawing process, since the frictional force acting on the tube blank by the mandrel is consistent with the direction of the drawing force, it is advantageous to reduce the drawing force and increase the reduction ratio of the pass. The tube blank is in close contact with the mandrel during the deformation process, thereby avoiding the possible breakage of the thin-walled and low-plastic tubes.

Floating plug drawing is recognized as a satisfactory process, which can obtain achieve an ideal surface roughness. Thin tubes can be efficiently fabricated during the drawing process. However, this process requires high process and lubrication conditions.