Introduction: Some people often confuse oxygen-free copper rod and low Oxygen Copper Rod. In order to reduce the occurrence of this situation, this article, based on years of practical experience in the use of practitioners, to help you judge correctly. There's a huge difference in performance, and if you look closely, you can see some of the things that distinguish them.

Oxygen-free Copper Rod and low oxygen copper rod production process is different, according to the name can be heard, the two main difference is the oxygen content. That's when someone said, "I know one with oxygen and one without. ". That sounds right, but it's not. Although called oxygen-free copper, this material also contains oxygen, but in negligible amounts. In addition, due to the different manufacturing process, there are some differences in performance, oxygen-free Copper Rod appearance is more bright, so when encountered two products at the same time, the general brightness is better is the oxygen-free Copper Rod.

1.Definition

Copper Rod with oxygen content between 200(175) and 400(450) PPM is produced by continuous casting and rolling with copper as raw material.

2.Production Technology

Copper Rod is the main raw material of cable industry. There are two kinds of mode of production: continuous casting and continuous rolling method and up drawing and continuous casting method.

There are many methods to produce low oxygen copper rod by continuous casting and rolling. The oxygen content is 200-400ppm. The invention is characterized in that after the metal melts in the shaft furnace, the copper liquid enters the closed mould cavity from the pouring pipe through the holding furnace, the clay groove and the Tundish, and is cooled with a greater cooling intensity to form a cast billet, and then is rolled several times, the original cast structure has been broken, the production of low oxygen copper rod for hot-working structure.

The oxygen-free Copper Rod is produced by up-drawing continuous casting in China. The oxygen content is below 20 PPM. After melting in induction furnace, the metal is continuously cast through graphite mould, then cold-rolled or cold-processed, the oxygen-free copper rod is cast structure.

The low oxygen copper rod is a hot-working structure, and the recrystallization form appears when the rod is 8mm. The oxygen-free Copper Rod is cast structure with coarse grain, which is why the oxygen-free Copper Rod has higher recrystallization temperature and needs higher annealing temperature. Because recrystallization takes place near the grain boundary, the microstructure of the oxygen-free copper rod is coarse and the grain size is very large. The grain boundary can reach several millimeters. Therefore, the grain boundary is less than that of the oxygen-free Copper Rod, therefore, high annealing power is required.

The successful annealing of oxygen-free copper requires that the annealing power should be 10-15% higher than that of oxygen-free copper when the rod is drawn but the wire has not been cast. After further drawing, there should be enough allowance for annealing power at later stage and different annealing processes should be carried out to ensure the softness of in-process and finished wire.

3.Oxygen content

Oxygen-free and low oxygen rod from oxygen content is easy to distinguish, oxygen content of oxygen in oxygen-free Copper Rod below 10-20 PPM, but some manufacturers can only do 50 PPM below. Low Oxygen Copper Rod in 200-400 PPM, good copper rod oxygen content control in general about 250 PPM.

The oxygen content of cathode copper used to produce copper rod is 10-50 PPM, and the solid solubility of oxygen in copper at room temperature is about 2 ppm. The oxygen content of a low-oxygen copper rod is typically between 200(175) and 400(450) PPM, so oxygen is inhaled in the copper liquid state. The oxygen content of the oxygen-free Copper Rod is usually below 10-50 PPM, and the oxygen content of the Rod can be as low as 1-2 PPM.

The oxygen in the low oxygen copper rod exists near the grain boundary in the form of copper oxide, which is common for the low oxygen copper rod but rare for the oxygen-free Copper Rod. The appearance of copper oxide in the grain boundary as inclusion has a negative effect on the toughness of the material. Oxygen in oxygen-free copper is very low, so the structure of this copper is uniform single-phase structure, which is good for toughness. POROSITY is uncommon in oxygen-free copper bars, but it is a common defect in low oxygen copper bars.

4.Drawing performance

The drawing performance of copper rod is related to many factors, such as impurity content, oxygen content and distribution, process control and so on.

The oxygen-free rod is usually drawn up, and the oxygen-low rod is continuous casting and rolling. Comparatively, the low-oxygen rod is more suitable for enameled wire performance, such as softness, springback angle and wire winding performance, but the low-oxygen rod is more severe for wire drawing condition. The same stretch of 0.2 filament, if the extension line conditions are not good, ordinary oxygen-free rod can pull, and the good oxygen rod will break; but if the good extension line conditions, the same Rod, oxygen rod may be able to pull double zero five, the average oxygen free rod can only stretch to 0.1. Of course, they are as thin as double zero, but they have to rely on imported oxygen-free copper rods. Both can be stretched to 0.015 mm, but the spacing between the wires is only 0.001 mm for low temperature grade oxygen free copper in cryogenic superconductors.

 (1)Effect of melting mode on s and other impurities

 (2)Entry of impurities into the casting process

 (3) Distribution of oxygen and its effects

 (4)Hydrogen Effect

5.Surface Quality

In the production of electromagnetic wire and other products, the surface quality of copper rod also needs to be put forward. It is necessary to draw the surface of copper wire with less copper powder and no oil. The quality of copper powder is measured by torsion test and the recovery of copper rod is observed after torsion to judge the quality of copper wire.

In the process of continuous casting and rolling, the oxide particles are rolled into the surface of copper wire with the rotation of the roll during the rolling process. Because the Cuprous oxide is a brittle compound with a high melting point, when rolled into a deeper Cuprous oxide, when stretched as a strip of polymer in a mold, it causes burrs on the outer surface of the copper rod, causing trouble for subsequent painting.

However, the oxygen-free Copper Rod produced by the up-drawing continuous casting process is completely isolated from oxygen by casting and cooling, and there is no subsequent hot rolling process, and the surface of the copper rod has no oxide rolled into the surface.

The oxygen-free Copper Rod is also divided into imported equipment production and domestic equipment production, but at present the imported products have no obvious advantages, and the produced copper rod products have little difference, as long as the copper plate is well selected and the production control is stable, home-made equipment can also produce 0.05 tensile copper rods. Imported equipment is generally Otokumpu Finland equipment, home-made equipment * * * Good should be the Shanghai Navy factory, production time * * * Long, reliable quality.

6. Applications

Low Oxygen Copper Rod and oxygen-free Copper Rod are electrical, is nothing more than wire and cable, enameled wire, flat wire, Copper Bar, applications are not too different. Oxygen-free copper rods are generally produced with electrolytic copper, and their electrical resistivity and workability are better than those of oxygen-free copper rods. Therefore, oxygen-free rods, such as enamelled wires, are generally used in the production of high-demand electrical materials, when applied to the motor, the heating condition is definitely better than the Hypoxia Rod. WHEN DRAWING COPPER WIRE WITH DIAMETER & GT. 1 mm, the advantage of low oxygen copper wire is obvious, and the drawing diameter & Lt. 0.5 mm copper wire is more superior. 6mm oxygen-free Copper Rod is used to produce flat copper wire, 3mm oxygen-free copper rod is used for drawing wire, producing wire copper core, enamelled wire, mainly used in wire, cable and motor. However, it is difficult to draw the filament below 0.5 mm when the rod is drawn under low oxygen. Therefore, now is basically a large size, low resistance requirements for electrical products with Low Oxygen Rod; small size, high resistance with oxygen-free Rod. But the sound line generally likes to use the oxygen-free Rod, this and the oxygen-free rod is the single crystal copper, the low oxygen rod is the polycrystal copper related.

7. Price advantage

On the one hand, the current domestic production of oxygen-free copper rods mainly uses the up-drawing method, which itself has the advantages of short process flow, high yield, low cost, low investment and so on, therefore, the price of oxygen-free copper rod is not much higher than that of ordinary copper Rod. On the other hand, the production process of oxygen-free copper has been developed in the past 20 years, and there are many improvements in the operation method and technology, for example, adding refining process in the process of up-drawing, the waste copper wire produced in the process of up-drawing power frequency furnace melting can be used without additional processing and transportation costs. With the perfect technology and production process, a mature oxygen-free copper rod manufacturing can make oxygen-free copper rod and ordinary copper rod cost almost the same.

Source: Tongxinbao

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