How to prevent the copper wire from turning black during the wire drawing process?
November 15, 2021
How to prevent the copper wire from turning black during the wire drawing process? 1. The area of the drawing oil pool is small, the return pipe is short and sealed, which causes slow heat dissipation and high temperature of the emulsion oil. 2. It is caused by copper wire annealing. a) The cooling water used for continuous retreat is generally tap water and groundwater. Because the water quality varies from place to place, the pH value of water quality in some areas is low, only 5.0 to 5.5, and the anti-oxidant oil film in the original drawing oil is cleaned. The annealed copper wire is easy to oxidize and turn black;
b) The finished copper wire drawn on an ordinary wire drawing machine is annealed on another annealing line. The cooling water does not use antioxidants, and the antioxidant time is short, and oxidation blackening will soon appear;
3. Some old factories still use annealing cylinders for annealing. The following reasons can also cause oxidation and blackening:
a) The annealing cylinder nut is not tightened, and the gas leaks after the carbon dioxide or high-purity nitrogen is flushed;
b) The temperature of the copper wire out of the cylinder is too high, exceeding 30°C;
c) The drawing oil is not well maintained and the PH value is too low; These conditions are more common in summer when the temperature is high. The drawing oil will be lost if used continuously, and the loss will be faster when the temperature is high. If new crude oil is not replenished in time, the fat content will be less at this time, and the temperature will be high. The temperature of the oil may also exceed 45°C, which can easily cause oxidation and blackening. 4. Due to the widespread use of high-speed wire drawing at present, its speed has been increased, and the relative heat dissipation time has been reduced, which brings a certain amount of space and time to oxidation. Therefore, it is recommended that the manufacturer pay more attention to the fat content of the drawing oil, the use temperature, and the pH value. The bacteria multiply faster in the yellow mold rain season in the spring, and the antiseptic and anti-mold agent can be used, and the antioxidant can be used in the summer to solve oxidation, Darkening is not a problem.
