Oxygen free copper is copper that does not contain oxygen or any deoxidizer residue. Oxygen free copper has high conductivity, good processability, weldability, corrosion resistance and low temperature performance, and no hydrogen embrittlement. Oxygen free copper has strict requirements for magazines. According to the content of copper and the quality of magazines, oxygen free copper is divided into TU1 and TU2 in China.

Process performance of oxygen free copper

1. Melting and casting process. Oxygen free copper is mainly melted by power frequency cored induction furnace. In order to ensure the quality of oxygen free copper, it is necessary to achieve "fine material sealing", that is, the raw material is electrolytic copper containing w (Cu) ＞ 99.97% and w (Zn) ＜ 0.003%. During smelting, attention must be paid to reducing the source of gas, covering it with calcined charcoal, and adding trace phosphorus as deoxidizer. The ingot is poured by semi continuous casting process under nitrogen protection or banquet cover. The casting temperature is 1150-1180 ℃.

2. Molding performance. The cold and hot working properties of oxygen free copper are excellent. It can stretch, calender, extrude, bend, punch, shear, spinning, upsetting, rotary forging, forging, thread pressing, knurling and winding. The malleability is excellent, which is 65% of that of forged brass. The hot working temperature is 800-900 ℃.

3. Welding performance. It is easy to carry out fusion welding, soft soldering, brazing, gas shielded tungsten arc welding and gas shielded metal arc welding. Its oxygen fuel gas welding performance is good. Shielded metal arc welding and most resistance welding methods are not recommended.

4. Cutting and grinding performance. The machinability of oxygen free copper is 20% of that of free cutting brass hpb63-3.

Main uses of oxygen free copper

Oxygen free copper has high purity, excellent conductivity, thermal conductivity, hot working performance and good welding performance, without "hydrogen disease" or very little "hydrogen disease".

It is mainly used for parts of electric vacuum instruments and meters. It is widely used in busbars, conductive bars, waveguides, coaxial cables, vacuum seals, vacuum tubes, transistor components, etc.