What Is Cold Drawing?

1. The purpose of cold drawing:

Cold drawing is a process of stretching the material at room temperature. During the stretching process, the material passes through the die. Through the compression of the material by the die, the cross-sectional area of the material can be changed according to the different shapes of the die.

The cold drawing of the material requires that the material can be pulled, so the drawing force of cold drawing must be higher than the yield strength of the material. At the same time, cold drawing should also ensure that the material does not break, so the drawing force of cold drawing needs to be less than the tensile strength of the material.

 

2. The influence of cold drawing on alloys

Size

The main function of cold drawing is to control the size of the material. During the cold drawing process, the mold will squeeze and deform the material. Manufacturers can control the size of the material after cold drawing by using different molds. It should be noted that if the size of the finished product differs greatly from the size of the material before cold drawing, cold drawing will be difficult to pull. In this case, the material should undergo multiple cold drawings. At the same time, because the cross-sectional area of the material decreases during the cold drawing process, the length of the material after cold drawing will increase.

 

Shape

Another function of cold drawing is to change the shape of the cross-section of the alloy material. The difference in shape is determined by the difference in the mold. For example, if the mold is square, then the cross-section of the material after cold drawing will be square. If a round bar is cold drawn in this way, a square bar will be obtained after cold rolling. It should be noted that if the material is to be deformed and cold drawn, the dimensions of the material before and after the cold drawing must be similar.

 

Surface

The third effect of cold drawing on the alloy is the surface. When the material passes through the mold, due to the friction between the mold and the material, the impurities on the surface of the material are removed. This will give the material a similar polished effect. For black bars, after cold drawing, they become bright bars. However, usually after cold drawing, we will still continue to polish or grind the material.

Mechanical properties

 

Cold drawing also has an impact on the mechanical properties of the alloy. During the deformation of the metal, a hardening phenomenon occurs, and cold drawing is also a cold deformation process, which also causes a hardening phenomenon. In some cases, cold drawing can be used to control the strength of the alloy. Of course, the hardening phenomenon caused by the cold drawing process can be eliminated through heat treatment.