The basic principle of wire drawing
1. Wire drawing
Wire stretching refers to the wire blank under a certain tension, plastic deformation occurs through the die hole, the cross-section to reduce the length of a pressure processing method.
2. The characteristics of stretching
(1) Stretched wire has a more precise size, smooth surface, cross-sectional shape can be diverse.
(2) can stretch a large length and a variety of diameter wire.
(3) Cold-based, drawing process, mold, equipment is simple, high production efficiency.
(4) larger energy consumption, deformation by certain restrictions.
3. The principle of stretching
Stretching is the scope of the pressure processing, the drawing process in addition to produce very little dust, the volume change is small, so before and after drawing the metal volume is basically the same.
4 factors that affect stretching
(1) copper, aluminum rod (wire) material. In other conditions are the same, pulling copper than aluminum tensile strength, pull aluminum easily broken, so pull the aluminum should take a greater safety factor.
(2) Tensile strength of the material. Material tensile strength of many factors, such as the chemical composition of the material, rolling process, tensile strength is high tensile force.
(3) the degree of deformation. The greater the degree of deformation, the longer the length of deformation in the die hole, thereby increasing the die hole on the line of positive pressure, friction also increases, stretching force also increased.
(4) the friction coefficient between wire and die hole. The greater the friction coefficient, the greater the tensile force. The coefficient of friction is determined by the finish of the wire and mold material, the composition and amount of lubricant.
(5) The size and shape of the die hole die area and sizing area. The larger the sizing area, the greater the tensile force.
(6) the position of the mold. Improper placement of the die or die block skew will increase the stretching force. Is the diameter and surface quality is not up to standard.
(7) Foreign factors. Wire is not straight, pull the line during the jitter, pay-line resistance, will increase the tensile force.