May 29, 2021. New energy cable The blackening of copper wire is caused by many factors, not only the formula, but also the state of the copper wire itself, rubber processing technology, rubber vulcanization technology, cable structure, sheath rubber formula, production environment and many other factors.
1. The area of the drawing emulsified oil pool is small, the return pipe is short and sealed, resulting in slow heat dissipation and high emulsion oil temperature.
2. It is caused by copper wire annealing.
① The cooling water for continuous withdrawal is generally tap water and underground water. Because the water quality varies from place to place, the PH value of water quality in some areas is low, only 5.5~5.0 (7.0~7.5 normally). The antioxidant oil film in the original emulsion is cleaned away, and the annealed copper wire is easy to oxidize and blacken;
② The finished copper wire drawn by an ordinary wire drawing machine is annealed on another annealing line, and the cooling water does not use antioxidants. The oxygen resistance time is short, and oxidation and blackening will soon occur.
3. Some old factories use annealing cylinders for annealing, so the following reasons can also cause oxidation and blackening:
① The nuts of the annealing cylinder are not tightened, and air leaks after flushing carbon dioxide or high-purity nitrogen;
② The copper wire temperature out of the cylinder is too high, exceeding 30 ℃;
③ The maintenance of wire drawing emulsion is not enough, and the PH value is too low.
These situations are common when the temperature is high in summer, and the emulsion will be lost if it is used continuously. If the temperature is high, the loss is fast. If new crude oil is not replenished in time, the fat content is low at this time. In addition, the temperature of the emulsion may also exceed 45 ℃, which is easy to cause oxidation and blackening.
4. On the other hand, because high-speed wire drawing is widely used at present, its speed is increased and the relative heat dissipation time is reduced, which brings a certain space and time for oxidation. Therefore, it is suggested that the manufacturer should pay more attention to whether the fat content, service temperature, PH value, etc. of the emulsion are appropriate. In the yellow and rainy season of spring, bacteria multiply rapidly, so bactericidal and anti mildew agents can be used. In summer, antioxidant can be used to solve the problems of oxidation and blackening.
① The deformation of the finished mold is too small
② The periphery and front of the mold insert are not sealed well
resolvent
Add a rubber pad in the outlet direction of the finished mold, and then screw down the finished mold to solve the problem of oil leakage.
It is a common mistake that the deformation of the finished mold is too small. The single mold deformation needs a minimum deformation, so the pressure generated can be greater than the yield limit of the metal, so that plastic deformation can be achieved, the size can be stable, and the single wire surface can have the light generated by cold drawing.
