Low oxygen copper rod
The electrolytic copper is melted while being added, and the molten copper water has no conditions for sufficient reduction. The entire melting process and the copper water discharge process cannot be isolated from oxygen, so the oxygen content is very high. Fuel for melting copper is generally gas. During the gas combustion process, it will directly affect the chemical composition of copper liquid, such as sulfur and hydrogen.
During the process of turning the copper liquid into a solid by the crystallization wheel of the casting machine, oxygen isolation cannot be performed, so a second large amount of oxygen is absorbed during the casting process.
Due to the constraints of various factors, the temperature is not easy to control. The temperature of the ingot casting in the rolling mill must be controlled at 850°C. The greater the upper and lower deviations, the greater the impact on the quality of the copper rod. If there are some problems in a certain link, it will cause serious problems. affect temperature control.
Oxygen-free copper rod
Oxygen-free copper rods are pure copper that does not contain oxygen or any deoxidizer residues. But in fact it still contains very trace amounts of oxygen and some impurities. According to the standard, the oxygen content is not more than 0.02%, the total impurity content is not more than 0.05%, and the copper purity is more than 99.95%. Generally produced with electrolytic copper, the resistivity is lower than that of low-oxygen copper rods. Therefore, in the production of products with strict resistance requirements, oxygen-free copper rods are more economical; the manufacture of oxygen-free copper rods requires higher quality raw materials.
According to the oxygen content and impurity content, oxygen-free copper rods are divided into TU1 and TU2 copper rods. The purity of TU1 oxygen-free copper rod reaches 99.99%, and the oxygen content is not more than 0.001%; the purity of TU2 oxygen-free copper reaches 99.95%, and the oxygen content is not more than 0.002%.
difference between the two:
1. About the inhalation and removal of oxygen and its state of existence
The oxygen content of the low-oxygen copper rod is generally 200 (175) - 400 (450) ppm, so the entry of oxygen is inhaled in the liquid state of copper, but the opposite is true for the oxygen-free copper rod of the up-drawing method. After keeping for a certain period of time, it is reduced and removed. Usually, the oxygen content of this rod is below 10-50ppm, and the lowest can reach 1-2ppm. Oxygen in oxygen-free copper is very low, so the structure of this copper is a uniform single-phase structure, which is beneficial to toughness.
2. Differences in inclusions, oxygen content fluctuations, surface oxides and possible hot rolling defects
The pullability of oxygen-free copper rods is superior to that of low-oxygen copper rods in all wire diameters. In addition to the above structural reasons, oxygen-free copper rods have less inclusions, stable oxygen content, and no possible defects caused by hot rolling. , The monitoring of oxygen is not strict, and the instability of oxygen content will directly affect the performance of the rod.
3. The toughness of low-oxygen copper rods and oxygen-free copper rods is different
Both can be pulled down to 0.015mm, but the low-temperature grade oxygen-free copper in the low-temperature superconducting wire has a pitch of only 0.001mm between filaments.
4. The wire-making process of low-oxygen copper rods is different from that of oxygen-free copper rods
The wire-making process of low-oxygen copper rods cannot be copied to the wire-making process of oxygen-free copper rods, at least the annealing processes of the two are different. Because the softness of the wire is deeply affected by the material composition and the rod making, wire making and annealing process, it cannot be simply said that the low-oxygen copper or the oxygen-free copper is soft and which is hard.
