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Annealing of aluminum products

Four heat treatment processes for aluminum products:
There are four such processes in the heat treatment process of aluminum products: annealing, normalizing, quenching(or hardening) and tempering.
Heat treatment of aluminum products is one of the most important processes in the production of aluminum materials. The focus of heat treatment is not to change the overall chemical composition of the workpiece, but to change the internal microstructure of the workpiece or the chemical composition of the surface of the workpiece, thereby improve the performance of the workpiece. Unlike other treatment processes, other processes mostly change the appearance and structure of aluminum products, while heat treatment generally improves the physical properties of aluminum products through heating processes.

What is annealing?
Annealing refers to heating the workpiece to an appropriate temperature, using different holding times according to the type of material and the size of the workpiece, and then slowly cooling the workpiece. The main purpose is to reduce the hardness of the material, improve the plasticity, reduce the residual stress, and improve the uniformity of the crystal structure and composition of the metal to facilitate subsequent processing. Annealing is divided into recrystallization annealing, stress relief annealing, spheroidizing annealing, and complete annealing according to different purposes.

What is normalizing?
Normalizing is to heat the workpiece to a suitable temperature and then cool it in the air. The effect of normalizing is similar to annealing, but the crystal structure obtained by normalizing is finer. Normalizing is often used to improve the cutting performance of the material, and sometimes also used for the final heat treatment of parts that do not require high physical properties.

What is quenching?
Quenching,also known as hardening, is a heat treatment process that rapidly cools the workpiece in a quenching medium such as water, oil or other inorganic salts, organic aqueous solutions after heating and holding the workpiece.

What is tempering?
After quenching, the material has an unbalanced structure, which is usually very hard and brittle. It needs to be held at a temperature higher than room temperature for a long time and then cooled. This process is called tempering.
The above four heat treatment processes belong to the process of heating, holding and cooling the workpiece. These four processes are an essential part of the heat treatment process of aluminum products, which largely determine the final aluminum product quality.