The basic principle of wire drawing of wire drawing dies

1. Stretching of the wire

The stretching of wire rod refers to a pressure processing method in which the wire blank is plastically deformed through the die hole under a certain tensile force, so that the cross-section is reduced and the length is increased.

2. Characteristics of stretching

(1) The stretched wire has a more accurate size, the surface is smooth and clean, and the cross-sectional shape can be varied.

(2) It can stretch wires of large lengths and various diameters.

(3) Mainly cold processing, simple stretching process, mold and equipment, high production efficiency.

(4) The tensile energy consumption is large, and the deformation is limited to a certain extent.

3. The principle of stretching

Stretching belongs to the scope of pressure processing, and the volume changes very little except for the very little dust produced during the stretching process, so the volume of the metal before and after stretching is basically the same.

4. Factors influencing stretching

(1) Copper and aluminum rod (wire) materials. When other conditions are the same, the tensile force of the copper wire is greater than that of the aluminum wire, and the aluminum wire is easy to break, so a large safety factor should be taken when the aluminum wire is drawn.

(2) The tensile strength of the material. There are many tensile strength factors of materials, such as the chemical composition of the material, the calendering process, etc., and the high tensile strength is the greater the tensile force.

(3) The degree of deformation. The greater the degree of deformation, the longer the length of the deformed section of the die hole, thus increasing the positive pressure of the die hole to the line, the friction force also increases, and the tensile force also increases.

(4) The coefficient of friction between the wire rod and the die hole. The greater the coefficient of friction, the greater the tensile force. The coefficient of friction is determined by the wire and die material finish, the composition and quantity of the lubricating fluid.

(5) The size and shape of the working area and sizing area of the wire die. The larger the sizing area, the greater the tensile force.

(6) The position of the wire formwork. Improper placement of the wire mold or skewed mold base will also increase the tensile force. It also makes the wire diameter and surface quality not up to standard.

(7) External factors. The wire is not straight, the jitter of the wire during the wire pulling process, and the pay-off resistance will increase the tensile force.