Copper bar is the main raw material of AAC Cable industry. There are two main production methods: continuous casting, continuous rolling and continuous casting. Due to different processes, the oxygen content and appearance of copper rods are also different. When the oxygen content is lower than 10ppm, it is called oxygen free copper rod; When the oxygen content is less than 10ppm, it is called oxygen free copper rod.
Low oxygen copper rod
Disadvantages of process D:
The electrolytic copper melts when it is added. There is no complete reduction condition for copper water. The whole smelting process and copper water process are inseparable from oxygen, so the oxygen content is very high. The fuel for molten copper is usually gas. In the process of gas combustion, it will directly affect the chemical composition of liquid copper. Sulfur and hydrogen are the most important factors.
Process advantages:
(1) High yield. Generally, the output of small units can reach 10-14 tons per hour.
(2) The layout of copper bar adopts plum blossom type, which is convenient for wire drawing machine.
(3) Bearing capacity, generally not more than 4 tons per plate.
Grade and characteristics of low oxygen copper rod: low oxygen copper rod
It is divided into three levels: T1, T2 and T3. The low oxygen copper bar is hot rolled, so it is a soft bar, code R.
(1) T1: production of low oxygen copper rod with high purity electrolytic copper as raw material (copper content greater than 99.9975%).
(2)T2：1 × The low oxygen copper rod (copper content above 99.95%) is made of electrolytic copper.
(3)T3：2 × The low oxygen copper rod (copper content above 99.90%) is made of electrolytic copper. Due to high purity electrolytic copper and 2 × Electrolytic copper is very few, generally 1 × Electrolytic copper is used as raw material, so the grade of low oxygen copper rod is T2R.
Oxygen free copper rod
Oxygen free copper rod is pure copper without oxygen or any deoxidizer residue. But in fact, it still contains a very small amount 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%.
It is generally produced by electrolytic copper, and its resistivity is lower than that of low oxygen copper rod. Therefore, oxygen free copper rod is more economical in the production of products with strict resistance requirements; High quality raw materials are needed to make oxygen free copper rods;
According to the oxygen content and impurity content, the oxygen free copper rod can be divided into TU1 and TU2 copper rods. The purity of TU1 oxygen free copper rod is 99.99%, and the oxygen content is not more than 0.001%; The purity of TU2 oxygen free copper is 99.95%, and the oxygen content is not more than 0.002%.
The difference between the two
Due to different manufacturing methods, low oxygen copper rod and oxygen free copper rod have their own characteristics.
1、 On the removal of oxygen and its existing state
Oxygen content of low oxygen copper rod is generally 200 (175) – 400 (450) ppm, so oxygen is inhaled into liquid copper. On the contrary, the oxygen in the oxygen free copper rod is reduced and removed after a certain period of time. Generally, the oxygen content of bar is below 10-50ppm, and the lowest is 1-2ppm. Oxygen content in oxygen free copper is very low, so the structure of copper is uniform and single-phase, which is conducive to toughness.
2. Difference between impurity content and existing hot rolling defects
The tensile properties of oxygen free copper bar are better than that of oxygen free copper bar in all wire diameters. In addition to the above microstructure reasons, the oxygen content of oxygen free copper bar is less and stable, there is no possible defect in hot rolling, the oxygen monitoring is not strict, and the oxygen content is unstable, which will directly affect the performance of copper bar. If the oxide on the surface of the bar can be made up in the continuous cleaning of the subsequent process, the problem is that there are quite a lot of oxide under the skin, which has a more direct impact on the broken wire.
3. The toughness of low oxygen copper rod is different from that of oxygen free copper rod
Both can be pulled to 0.015 mm, but the distance between low temperature grade oxygen free copper wires is only 0.001 mm.
4. Low oxygen copper rod
The wire making process of copper rod is different from that of oxygen free copper rod. The wire making process of low oxygen copper bar should be the same as that of oxygen free copper bar, at least the annealing process of the two should be different. Because the softness of wire rod is greatly affected by material composition, bar manufacturing, wire manufacturing and annealing process, it can not be simply said that low oxygen copper or oxygen free copper is soft or hard.
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