Introduction to Basic Knowledge of Wire Drawing Dies
The reason for the ring groove in the drawing die is that the resistance of the metal wire entering the die hole when the cross section changes and the periodic pressure caused by the vibration of the metal wire during drawing lead to the fatigue failure of the die.
The appearance of mold ring grooves promotes wear of mold holes. After forming a ring groove in the die hole of the wire drawing mold, small particles of the peeled mold core material are loosened in the ring groove, and the working area and sizing area are ground like abrasive. The wires entering the mold hole act as mold rods to promote wear of the mold hole. At this point, the friction between the mold hole and the metal wire increases, resulting in high temperatures, and the wear process proceeds.
Generally speaking, the wear of the drawing die during wire drawing is divided into three stages. The first stage is a sharp wear stage on the surface of the mold hole, the second stage is a low stable speed wear stage, and the third stage is a high-speed wear stage with the appearance of wear grooves on the surface of the mold hole.
Effect of Drawing Conditions on the Life of Wire Drawing Die
One side depends on its own mass, and the other side also depends on tensile conditions
(1) Impact of reduction rate
During the stretching process, the steel wire mold will exert pressure on the steel wire, and when the steel wire deforms, the steel wire mold wall will also exert pressure. The greater the expansion ratio, the stronger the pressure generated by the hole wall on the metal wire, and the stronger the reaction force generated by the metal wire on the hole wall. If the force is greater than the tensile force of the mold itself, the rope shape will collapse.
(2) Effects of lubricants
During the drawing process, whether the quality and supply of lubricants have a sufficient impact on the life of the steel wire mold. Lubricants have the functions of lubrication, cooling, cleaning, and rust prevention during wire drawing.
(3) Influence of surface quality of metal materials
The presence of oxide layers, sand, or other impurities on the surface of metal materials can adversely affect the life of the drawing die. Because the oxide layer on the metal surface is hard and brittle, after the metal material passes through the mold hole, the mold hole of the wire, like abrasive, immediately wears away, and the surface is injured. When stacking fabrics that must be pickled before stretching, please pay attention to the cleanliness of the stacking area and avoid contact with sand and other impurities.