The comparison of low-oxygen copper rod and oxygen-free copper rod

Copper is the main raw material of the cable industry. Due to the different production methods and manufacturing processes of various enterprises, there are two main production methods-continuous casting and rolling method and upward continuous casting method. There are many production methods for continuous casting and rolling of low-oxygen copper rods. The characteristic is that after the metal is melted in the shaft furnace, the copper liquid passes through the holding furnace, chute, and tundish, and enters the closed mold cavity from the pouring pipe. The cooling intensity is cooled to form a cast billet, and then rolled in multiple passes. The low-oxygen copper rod produced is a hot-worked structure. The original casting structure has been broken, and the oxygen content is generally between 200 and 400 ppm.

Oxygen-free copper rods are basically all produced in China by the upward continuous casting method. After the metal is melted in an induction furnace, the graphite mold is used for upward continuous casting, and then cold-rolled or cold-worked. The oxygen-free copper rods produced are cast structure and contain oxygen. The amount is generally below 20ppm. Whether it is a low-oxygen copper rod or an oxygen-free copper rod, there is a big difference in many aspects such as the structure, the distribution of oxygen content, and the form and distribution of impurities. So what kind of copper is good copper?

         The production of copper rods by continuous casting and rolling is mainly through the combustion of gas to melt the copper rods. During the combustion process, through oxidation and volatilization, some impurities can be reduced to a certain extent into the copper liquid. Therefore, the continuous casting and rolling method has relatively high requirements for raw materials. Lower. Upward continuous casting produces oxygen-free copper rods. Because they are melted by an induction electric furnace, the "patner green" and "copper beans" on the surface of the electrolytic copper are basically melted into the copper liquid.

         In the production process, the continuous casting and rolling process needs to transfer the copper liquid through the holding furnace, the chute, and the tundish, which is relatively easy to cause the refractory material to peel off. During the rolling process, it needs to pass through the rollers, which will cause the iron to fall off, which will damage the copper rods. Cause external inclusions. In hot rolling, the rolling of oxides on the skin and under the skin will adversely affect the drawing of the hypoxic rod. The production process of the upward continuous casting method is short. The copper liquid is completed by the submerged flow in the conjoined furnace, which has little impact on the refractory materials. The crystallization is carried out in the graphite mold, so there may be fewer pollution sources and impurities in the process. There are fewer opportunities to enter.

         Oxygen content has a significant effect on the drawability of low-oxygen copper rods. When the oxygen content increases to the optimal value, the wire breakage rate of the copper rod is the lowest. This is because oxygen acts as a scavenger in the process of reacting with most impurities. Appropriate oxygen is also conducive to removing hydrogen in the copper liquid, generating water vapor to overflow, and reducing the formation of pores. The best oxygen content provides the best conditions for the wire drawing process.

        The oxygen content of the oxygen-free copper exceeds the standard, the copper rod becomes brittle, the elongation decreases, the port of the stretched pattern is dark red, and the crystal structure is loose, which can also cause the conductivity of the oxygen-free copper rod to decrease. Therefore, the upward continuous casting process and product quality must be strictly controlled.

In the process of producing magnet wire and other products, the surface quality of the copper rod also needs to be required. The surface of the copper wire needs to be drawn without burrs, less copper powder, and no oil stains. And through the torsion test to measure the quality of the surface copper powder and observe the recovery of the copper rod after twisting to determine its quality.

There is a difference from the raw materials of rod-making to the economy of wire-making. The manufacture of oxygen-free copper rods requires high-quality raw materials. Generally, when drawing a copper wire with a diameter of >1mm, the advantages of a low-oxygen copper rod are more obvious, and an oxygen-free copper rod is more superior to drawing a copper wire with a diameter of <0.5mm.

The wire-making process of low-oxygen copper rods is different from that of oxygen-free copper rods. The wire-making process of the low-oxygen copper rod cannot be copied to the wire-making process of the oxygen-free copper rod, at least the annealing process of the two is different. Because the flexibility of the wire is deeply affected by the material composition and rod-making, wire-making and annealing process, it cannot be simply said that low-oxygen copper or oxygen-free copper is soft and hard.

All in all, the advantages of the oxygen-free copper rod produced by the copper casting machine are:

1. When the copper wire needs to be drawn below 0.5mm, the advantage of the copper casting machine is more obvious. (Especially when the ultra fine wire below 0.06mm is produced, the low-oxygen copper rod will be broken.)

2. The copper casting machine can produce cable-level copper rods even if scrap copper is used.

3. The copper casting machine can also directly produce conductors for large-size cables or enameled wires.