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

(1) The drawing emulsion oil pool area is small, the return pipe is short and sealed, resulting in slow heat dissipation, leading to high emulsion oil temperature.

(2) Copper wire annealing causes blackening of color. First, even pulling back the cooling water is generally used tap water, groundwater, due to the water quality is not the same everywhere, some areas of water quality PH value is low, only 5.5 ~ 5.0 (normal is 7.0 ~ 7.5), the original emulsion in the antioxidant film are cleaned off, the annealing of the copper wire is easy to oxidize, blackened; Second, in the ordinary wire drawing machine pulled a finished product of the copper wire in the annealing line in another annealing line, the cooling water also No use of antioxidants, antioxidant time is short, there will soon be oxidized black phenomenon;

(3) Some old factories still use annealing cylinders to anneal. The following reasons will also cause oxidation, blackening: First, the annealing cylinder nut is not tightened, flushing carbon dioxide or high-purity nitrogen leakage; Second, out of the cylinder of the copper wire is too high a temperature, exceeding the 30 ° C; Third, the wire drawing emulsion maintenance is not enough, the PH value is too low; these cases are more common in summer when the temperature is high, the emulsion will be used without stopping the loss of high temperatures, then loss of faster. When the temperature is high, the loss is faster, if you do not replenish the new crude oil in a timely manner, the fat content is very small at this time, coupled with high temperatures, the temperature of the emulsion may be more than 45 ℃, it is easy to cause oxidation and blackening.

(4) Another situation is that, due to the current widespread use of high-speed drawing, its speed increased, the relative heat dissipation time is reduced, to the oxidation of a certain amount of space and time, therefore, it is recommended that manufacturers pay more attention to the fat content of the emulsion situation, the use of temperature, PH value, etc. Whether it is appropriate to use the yellow moldy rainy season in the spring, the bacterial reproduction of the fast, you can use fungicidal antifungal agent, available in the summer antioxidant to solve the problem of oxidation, Blackening problem will not be a problem.