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Annealing in copper casting

Update:13 Jul 2019
Summary:

Annealing is an important step in the casting of copper […]

Annealing is an important step in the casting of copper sleeves. The accuracy of the annealing process can determine the strength and wear resistance of our copper sleeves after cooling. Therefore, annealing is a technically demanding work. Be proficient in this annealing process.

An important parameter for annealing in copper casting is heating temperature. The choice of annealing temperature is controlled according to the phase diagram of copper alloy. The phase diagrams of different copper alloys will have different appearances. The correctness can guarantee the qualification of annealing.

The following two methods of annealing are described: 1. Diffusion annealing, which is mainly applied to some casting annealing methods of tin bronze copper sleeve, silicon bronze copper sleeve, and aluminum bronze copper sleeve. In a specific method, each element of the copper sleeve alloy is heated to a high temperature of the phase line, and after being completely melted, the temperature is slowly lowered to cause solid diffusion of each element in the alloy, thereby reducing segregation. This also causes the temperature of the diffusion annealing to be too high, and the heat retention time is shortened in order to spread the temperature of each element as quickly as possible.

2. Gravity annealing, which is mainly used for annealing during equilibrium heating and cooling. Look at the literal meaning we should know to let the pre-existing annealing with large gravity, and other elements to anneal. The important thing to note is that it should be heated or cooled slowly. If the speed is too fast, the annealing of gravity elements will be uncontrollable.

This is the two methods of annealing. After the copper sleeve casting is cooled and annealed, a transparent film will be formed. This film will have good oxidation resistance to the copper sleeve.