Why should we strictly control the length and compression Angle of the drawing die?

Do you encounter the following situations in the production of metal wire?

① The diameter fluctuates greatly during the drawing process

② It didn't take long for the drawing die to crack

③ The drawing die life is too short

④ The surface of the wire is cracked and rough

Wire drawing die is a very important expendable die in the drawing production of various metal wires. The cost of wire drawing die accounts for a very large proportion of the drawing cost. As a wire manufacturing enterprise, how to reduce the cost, obtain stable long-term drawing, accurate size, and better surface quality is very important. But how? Of course, it is difficult to achieve without a high-quality wire drawing die. Under certain conditions of the die material, the pass structure is the key factor to determine the quality of the wire drawing die, because different drawing conditions need to have different pass structures to adapt to it, only in this way can the life of the wire drawing die be extended and large economic benefits created. Therefore, the pass structure of the wire drawing die is crucial to the drawing wire enterprises. Today we focus on understanding the two most important areas of the lower drawing die - the reduction zone and the sizing zone.

1. Reduction area

The reduction zone is the area where the wire is stretched and deformed. The Reduction Angle is the main parameter of the reduction zone of the wire drawing die. The size of the Reduction Angle plays a decisive role in the size and distribution of the pressure acting on the hole in the wire drawing die, the size of the drawing stress and the mechanical properties of the drawn wire.

If the Angle of the reduction zone is too large, the deformation rate of the metal material will increase and the deformation zone will become smaller during the control process, making the drawing die produce a lot of heat, burn the lubricating powder, and make it ineffective, which seriously affects the drawing effect of the wire. At this time, if the reduction area is not cooled, it will directly affect the drawing quality of the metal wire; If the Angle of the reduction zone is larger or the reduction rate is smaller, the metal material will be closer to the bearing zone in the drawing, the deformation is larger, it is difficult to reach the specified area of the bearing zone, so that the surface of the concave and convex phenomenon, if the material is soft, the ellipse phenomenon will occur during the drawing process. At this time, the area of the lubrication area increases, which can provide a better lubrication effect, but it is not the case, on the contrary, the lubrication powder due to the increase in the surface lifting area, the eddy current effect, the reverse flow from the die hole, thereby reducing the lubrication effect, and eventually lead to the formation of cracks on the surface of the wire, or scratch marks. Therefore, the compression zone Angle can not be too large, too large easy to make the lubrication powder lose the lubrication effect, and then affect the metal wire drawing quality.

What happens if the reduction Angle is too small? When the reduction Angle becomes smaller, it will also cause the drawing die to generate a lot of heat, and then make the lubrication powder ineffective. Because when the Angle is too small, the contact point of the metal material is close to the top of the reduction zone, which increases the deformation area, resulting in an increase in the useless power of the wire drawing die and a lot of heat. In addition, when the lubrication area is reduced, the lubrication function is reduced because the amount of lubrication is also reduced. In turn, the drawing quality of the wire is affected. When the tensile stress increases, the diameter of the bearing zone will become larger, making the ellipse phenomenon easy to appear, and then lead to the metal wire easy to break and shrink.

2. Bearing area

The bearing area is the control part of the die aperture size, and the final size of the metal wire can be obtained through this area. Reasonable length of bearing zone can improve flatness, dimensional accuracy, surface roughness quality and die life.

The longer the bearing area, the larger the contact area between the wire and the die hole, the greater the friction will be greatly increased, so the long bearing area will especially increase the tensile force value, but the tensile stress must be greater than the tensile strength limit of the wire, the stretching process can be carried out, otherwise it will cause the phenomenon of broken wire, so that the stretching can not be carried out. Therefore, it is very important to find a suitable bearing zone length for drawing different kinds of metal wire.

The bearing zone must be straight and of reasonable length. The bearing area is too long, the drawing friction increases, the wire is easy to cause shrinkage or wire break after pulling out the die hole, the bearing area is too short, it is difficult to obtain a stable shape, accurate size and good surface quality of the wire, and the die hole will soon wear out.

To sum up, as a wire manufacturer, it is essential to obtain stable and long-term drawing, accurate size, better surface quality, reduce costs, and create large economic benefits for the detection of wire drawing die pass structure.