Smelting of copper wire

Copper has become the first choice and main material in the field of electronics and power industry because of its good electrical and thermal conductivity. In order to achieve the required performance standards, almost all copper is of high purity. This article mainly discusses the reasons for doing this, with special attention to some fundamental principles of copper wire smelting

1. Conductor requirements: Great progress has been made in recent years in interpreting the electronic properties of precious metals, namely copper, silver and gold. These elements exhibit high electrical conductivity because their conducting electrons have little resistance to the movement of electric fields. Copper is an especially good conductor because the outermost electrons have too much free space between them to collide. And its resistivity is inversely proportional to the vastness of the space.

There are several conductive metals that are lighter than copper but require larger cross sections to carry the same amount of current, so they are not desirable if space saving is required. (For example, in some small electric motors). So when being overweight became a problem, people started using aluminum. Copper has the best performance characteristics required for commercial applications, so silver is not used because of its high price.

2. Applications: Copper is one of the most widely used rare metals in its pure form rather than in alloy form. There are about fifty different forging alloys with a minimum copper content of 99.3%, although only a small fraction is used industrially as an electrical conductor. The most common of these alloys is electrolytically toughened copper, which consists of a metal of this purity that can be alloyed with oxygen in the 100-650 PPM range. However, it is recommended not to use ETP copper in hydrogen because it will be affected by hydrogen embrittlement when exposed to these temperatures. In such an environment, either oxygen - free copper or electron - free copper is used. Applications in power voltages in silver-containing copper are rather limited because of its high strength and weak resistance to temperature increases.

3. Production of copper rods and wires: Until the 1970s, almost all copper was produced by the batch process, which is as follows: Molten copper is poured and solidified into special castings called "wire ingots", the rods are then reheated in a slightly restricted protective atmosphere, and the cast tree is then broken down into rod forms by hot-pressing in the air. It is then dropped in 10% sulfuric acid to remove the oxide from the top, creating a longer coil by connecting one end to the other. Today virtually all copper rods are made by a continuous casting and rolling process. The benefits of continuous casting are: smaller microseparation of impurities, reduced surface copper oxide particles, reduced steel content in contact with the roll, almost all welds avoided, and reduced overall processing costs.

Oxygen and copper are deliberately made into alloys to act as purifiers for dissolving hydrogen and sulfur, thus forming the gases H2O and SO2 in melting. If oxygen composition is kept in check, small bubbles form that, under the right conditions, cancel out about 4% of the shrinkage during the transition from liquid to solid. If the pores formed are not very large, they can be eliminated during hot pressing.