Annealing of a metal alloy is a heat treatment which consists in heating to a usually lower than the melting temperature, followed by the appropriate duration of stay and usually by a slow cooling in the furnace.
The final aim of the treatment is to develop the following stages of balance:
• Chemical balance: reduction of the minor segregation;
• Structural balance: transformation of the metastable phases;
• Mechanical balance: reduction of the residual internal stresses, hardening included.
This process is used mainly on steels, copper but also aluminum and its alloys to prepare them for subsequent processing steps, making the sweeter and more homogeneous material.
But there are also applications of electronic microcircuits, when you have to reduce tensions within the crystal lattice of the silicon.
The Annealing alters the microstructure of the material, changing its properties such as flexibility and hardness. Typical result is the removal of the defects of the crystalline structure.
Annealing is used in cases where you want to increase the ductility of metals and to decrease their hardness; the alterations of the mechanical properties, trough annealing, are really significant for several reasons.
• It improves the formability of a material. The hard and the fragile ones may be difficult to bend or to press without creating a fracture of the material. The annealing helps to eliminate this risk.
• It can also improve the workability; an extremely fragile material can cause an excessive wear of the tool: reduce the hardness of a material trough the annealing can reduce the wear of the used tool.
• It removes the residual stresses; they may create cracks and other mechanical complications, and it is better to eliminate them as soon as possible.
The Galli models, from low furnace at higher temperatures + 260 ° C, + 300 ° C, + 500 ° C, + 800 ° C, + 1100 ° C + 1200 ° C + 1400 ° C and 1800 ° C they offer solutions to the annealing or annealing processes.
Annealing is also used for applications on electronic microstructures, for example when you want to decrease the tensions in the crystalline grid of silicon; in fact, the typical result in these cases is the removal of defects in the crystalline structure.