The domestic drawing die has the following characteristics and has been improved:
① The entrance angle is small. Because the wire first contacts the entrance area of the die core in the drawing process, the cone angle of the entrance area is very small, which not only increases the contact area between the wire and the inner hole, increases the friction, but also prevents the introduction of lubricant, which makes the lubrication effect of the medium in the drawing process worse, and seriously affects the service life of the die.
Foreign wire drawing die products increase the import angle, effectively avoid the scratch between the wire drawing die and the wire drawing die, and introduce more lubricants, improve the lubrication effect, reduce the wear of the die core. This change improves the surface quality of wire rod and the service life of drawing die.
② The working area is short. Compared with domestic drawing dies of the same specification, the working area of foreign drawing dies is generally much longer. The longer working area is conducive to the reduction and uniform distribution of friction in the drawing process, reducing the wear of the inner hole of the drawing die, and improving the service life of the drawing die. The long and narrow working area can reduce the gap between the drawing die and the wire drawing die. Under high pressure, more lubricant can be forced into the middle and inner hole of the wire drawing to produce better lubrication pressure. In the process of drawing, the temperature of the inner hole is lower, the drawing force is reduced, and the metal flow is more uniform, which is conducive to improving the drawing speed and surface quality. In addition, this type of work area design prevents lubricant from flowing out of the inlet end of the drawing die. However, due to the short working area of the die and the small effective use area in the hole, not only the friction and wear are increased, but also the raw materials are wasted and the cost is increased.