Compression zone of drawing die
The compression zone is the area where the wire is stretched and deformed. The angle of the compression zone (compression angle) is the main parameter of the compression zone of the drawing die. The size of the compression angle affects the size and distribution of the pressure acting on the inner hole of the drawing die, and the drawing stress. The size and mechanical properties of the drawn wire play a decisive role.
If the angle of the compression zone is too large, the deformation rate of the metal material will increase during the control process, and the deformation zone will become smaller, causing the drawing die to generate a lot of heat, scorching the lubricating powder, and making it ineffective, thereby seriously affecting the wire drawing effect . At this time, if the compression zone is not cooled, it will directly affect the drawing quality of the metal filament; if the angle of the compression zone is larger or the compression rate is smaller, the metal material will be closer to the sizing belt during drawing , The deformation is larger, it is difficult to reach the specified area of the sizing belt, and the surface of the sizing belt will form unevenness. If the material is soft, the ellipse phenomenon will also occur during the drawing process. At this time, the area of the lubrication area increases, which can logically provide a better lubrication effect, but this is not the case. On the contrary, the lubricating powder will flow out from the die hole in the reverse direction due to the increase of the surface relief area, resulting in a vortex effect. The lubricating effect will eventually lead to the formation of cracks or scratch marks on the surface of the metal wire. Therefore, the angle of the compression zone should not be too large, too large will easily cause the lubricating powder to lose its lubricating effect, which will affect the drawing quality of the metal wire.
What if the angle of the compression zone is too small? When the angle of the compression zone becomes smaller, the drawing die will also generate a lot of heat, which will cause the lubricating powder to fail. Because when the angle is too small, the contact point of the metal material is close to the top of the compression zone, which increases the deformation area, which in turn leads to an increase in the useless power of the drawing die and a large amount of heat. In addition, when the area of the lubrication area is reduced, since the amount of lubrication is also reduced, the lubrication function is reduced. This in turn affects the drawing quality of the metal wire. When the tensile stress increases, the diameter of the sizing belt will become larger, making the ellipse phenomenon easy to appear, which in turn leads to the easy breakage and shrinkage of the metal wire.