Why does the copper wire of the cable and wire become black?

(1) The area of the drawing emulsification oil pool is small, the return pipeline is short and sealed, resulting in slow heat dissipation and high temperature of the emulsified oil.

(2) It is caused by the annealing of the copper wire. First, the cooling water used in the continuous retreat is generally tap water and groundwater. Since the water quality varies from place to place, the PH value of the water quality in some areas is low, only 5.5~5.0 (normally 7.0~7.5). The anti-oxidation oil film has been cleaned off, and the annealed copper wire is easy to oxidize and turn black; the second is to anneal the finished copper wire drawn by the ordinary wire drawing machine on another annealing line, and the cooling water does not use antioxidants, and the anti-oxidation time Short, the phenomenon of oxidation blackening will appear soon;

(3) Some old factories still use annealing cylinders for annealing. The following reasons can also cause oxidation and blackening: First, the annealing cylinder nut is not tightened, and air leaks after carbon dioxide or high-purity nitrogen is flushed; second, the cylinder is discharged When the temperature of the copper wire is too high, exceeding 30 °C; the third is that the maintenance of the drawing emulsion is not enough, and the PH value is too low; these situations are more common when the temperature is high in summer, and the emulsion will be lost if it is used continuously, and when the temperature is high, it will be lost. Faster, if new crude oil is not replenished in time, the fat content is very small at this time, coupled with high temperature, the temperature of the emulsion may also exceed 45 °C, which will easily cause oxidation and blackening.

(4) Another situation is that due to the common use of high-speed wire drawing at present, its speed is increased, and the relative heat dissipation time is reduced, which brings a certain space and time to oxidation. Therefore, it is recommended that manufacturers pay more attention to the fat content of the emulsion. Whether the temperature and pH of use are appropriate, the bacteria multiply rapidly in the spring yellow mold and rainy season, you can use bactericidal and mildew proofing agents, and in summer, antioxidants can be used to solve the problems of oxidation and blackening.

Reasons:

1. The deformation of the finished mold is too small;
2. The periphery and front of the mold sleeve are not well sealed.

Solution:

Add a rubber pad to the exit direction of the finished mold, and then press the finished mold with threads to solve the problem of oil leakage.

The deformation of the finished mold is too small, which is a common mistake. The single-mode deformation requires a minimum amount of deformation, so that the pressure generated may be greater than the yield limit of the metal, plastic deformation can be realized, and the size can be stable. Only single-line surfaces will have the light generated by cold drawing.