Metal copper atomic number 29, density is 8.92g/cm3, melting point 1083.4 ℃, with good thermal and electrical conductivity, but in the humid air in the surface of the metal copper and oxygen chemical reaction occurs, generating Cu2 (OH) 2CO3, that is, the copper green, usually cable production plants in the copper oxidation of more than show the surface of the blackened, it is the existence of this cable copper conductor surface oxidation phenomenon that plagues the Many cable companies.

We observed in the daily production and a lot of information research found that through the selection of high-quality copper rod, effective control of the drawing process and emulsion concentration and temperature, passivation treatment of copper conductor stranded or bunch stranded copper wire surface, the follow-up process optimization and other means, will effectively control the quality of the cable copper conductor to prevent the oxidation of the conductor, it will greatly improve the efficiency of the work, reduce the frequency of rework to reduce the cost and improve the inner The beneficial effect of product quality. In this paper, we will take Guangdong Zhujiang wire and cable production as an example, from the arrival of copper rod production plant, storage, drawing, stranding, core storage to insulation extrusion, to analyze the effective control measures for each step.

Cable copper conductor

First, the wire and cable production process of copper conductor anti-oxidation control

Copper metal cable from the principle of the main physical methods to block copper and humid air contact, cathodic protection redox method to prevent the oxidation of copper conductors, chemical methods in the production of passivation film on the surface of the copper conductor to prevent oxidation, or in the conductor surface spraying of special liquids to be protected. Guangdong Pearl River wire and cable production, for example, the main methods of anti-oxidation control of each process.

1.1 Copper rod into the factory before transportation, testing and storage

Most of China's cable companies with copper basic outsourcing, and most companies tend to ignore the control of the transportation process before the copper rod into the factory, in the south of the Yangtze River and the coastal belt (Jiangsu, Zhejiang, Fujian and Guangdong) summer is long and rainy, the copper rod is basically transported to the company through the heavy trucks, through the author's understanding, many cable companies have not formulated the corresponding copper rod supplier transportation specifications, packaging specifications for the rainy days of the summer, etc. system, which makes it often appear that copper rod Supplier shipment of copper rod surface intact without oxidation black, and arrived in front of the cable business users appear copper rod surface black phenomenon, bringing unnecessary trouble.

Copper rod into the factory inspection in accordance with GB/T 3953-2009 or the cable enterprise standard, there are strict procedures. Copper rod storage of general cable companies are placed in the warehouse, the general business has a more stringent storage management approach, in the copper rod storage, especially in the summer rainy days, be sure to use plastic sheeting or plastic film to cover the copper rod, with the simplest physical barrier method to prevent the copper rod and humid air contact system, which is often ignored by the cable companies. Copper rod in the workshop when the collar must be one by one copper rod rolls for visual inspection of whether there is a black phenomenon, from the source of production to control.

1.2 Control of copper rod drawing process

This stage of the most commonly used in power cables, for example, 8mm copper rods, now drawing generally use continuous annealing of copper Dala, need to go through the release of the wire, drawing and annealing, cooling, drying, closing and other processes, preferred selection of the corresponding specifications of the mold, not too small, such as too small will be forced to make the lattice of the metal copper variations, exacerbated by the sharp rise in metal temperatures.

Check the concentration of emulsion before starting the machine, make sure the concentration is qualified, in the process of unwinding, should keep the unwinding tension stable, even, not excessive trembling (trembling is unavoidable), the operator should pay close attention to the change of annealing temperature in the process of wire drawing, the conductor hardening, elongation becomes smaller, the conductor DC resistivity rises, the copper conductor should not have residual emulsion on the surface of copper conductor when drawing waiting for the circle, this requires the operator to identify the operator visually. Recognition, after drawing under the disk with a transparent plastic film sealed, stored in a dry environment, to flow, but most cable companies because of the copper wire package film trouble and omit the package film process. Just pulled into a circle of the conductor surface temperature is higher than room temperature, such as rainy season will potentially oxidize the risk.

1.3 copper wire stranding (bunching) and chemical crosslinking extrusion process

Take copper wire stranding as an example, in the conductor stranding process, the monofilament to regular stranding or irregular stranding and other ways of stranding, after the role of the various compression molds, the copper conductor temperature after the mold than before the mold has a greater increase, especially tightly pressed conductors, fan-shaped conductors, etc., and the frame stranding machine is currently no on-line annealing or cooling device, so the outer layer of the copper conductor is easy to oxidize, in the stranding before the selection of appropriate stranding molds, tightly pressed wheels, rows of wire, and the selection of suitable stranding molds, tightly pressed wheels, rows of wire. Adjust the take-up and payoff tension, equipment adjustment is complete, the operator visual observation of the upper plate copper wire and payoff frame center copper wire surface finish, to ensure that there is no obvious black spots, and then start the machine.

General cable companies will be in the stranding process (frame stranding machine, cage stranding machine) in the application of antioxidant, antioxidant formula is about 0.3% benzotriazole alcohol solution, the operation method is to incorporate antioxidant into industrial alcohol, with the conveyor