There are a lot of different reasons why parts or components may need to go through the copper annealing process. This is a common process with all types of metals and it is used to address the natural hardening process that occurs when many different types of metals are worked.
In its initial state in sheets, tubing or wire, copper is relatively soft, pliable and easy to work with. Through the process of bending and shaping copper, strain will develop within the metal itself. With multiple bends and shaping a process known as strain hardening will occur and actually changes the formation of the grains within the copper.
When the hardening occurs and the structural component of the copper changes, it will be impossible to continue to work with the copper as it becomes rigid and less pliable or workable.
Copper Annealing Process
The copper annealing process is designed to allow that strain in the copper to be released, allowing the grains to realign and go back to their original orientation before the work hardening occurred.
With the high temperatures of copper annealing those distortions in the internal structure of the metal, which are known correctly as dislocations, are removed from the internal structure. It is important to use the right heat to release the strain but to apply too much heat to cause the copper to melt.
The copper annealing process is typically completed at about 700 degrees Fahrenheit, which is approximately half of the melting point of the alloy. This temperature is maintained for a specific amount of time and then the copper component or part is allowed to cool slowly, allowing the molecular structure to align within the metal and all the dislocations and any existing irregularities caused by working to be replaced by new grains that do not have any strain.
It is important to note that once a part has completed the copper annealing process it does not resume its shape, but it can be bent or worked back into the original shape. In this way, annealing allows more complex work on a part or component that wouldn’t be possible due to strain or work hardening after the copper had been bent or worked a few times.
The task of copper annealing, while straightforward in process, requires specific attention to time, temperature and the cooling process. It is essential for many components and allows ongoing work on the metal, component or part that would not be possible without the process.
