Heat Treating Methods
Metal making is a versatile process, which produces everything from marine parts to aerospace and electronic tools. While foundries use an aluminum casting as a raw material to produce final casting, there are applications that necessitate better mechanical properties that cannot be provided by the raw material used in as cast condition. Such mechanical properties can comprise of those related to the metal’s composition like hardness, resistance to abrasion, and ductility.
Die casters heat treat the casting with extreme and fluctuating heat in order to improve the material’s properties and create a final casting with a desired shape. Below are some of the metallurgical methods used by foundries to produce a final casting irrespective of the application they serve.
Quenching
Quench hardening red-hot metal into water or oil is a method used to cool off the component and change its structure. This is one of the methods to heating metals and one that takes cues from metalworking. It makes most of the metals, helps to make it more resistive to abrasive materials, and hardens its surface. Quenching can make castings more brittle too.
Annealing
This is another heat-treating method used in metal casting, and one that is also inspired from metalwork. It is an act of heating the material in a way that the heat reaches near to the melting point, and then allows the material to cool off gradually. This helps to relax the metal’s structure, all the while making it less brittle. Foundries do annealing following quenching in order to retain the metal’s hardness, release its internal stresses, as well as stop the metal from becoming brittle.
Age Hardening
This is another technique in metal casting, wherein heat is exerted to the casting for close to twenty hours. It is a time-consuming heat treat treating process, which blocks the ability of the molecule to freely dislocate and results in a material that is less ductile with high yield strength.
Heat-treating metals comprising aluminum involves some amount of balancing from the part of the die caster. For instance where the material’s one mechanical property enhances, another one gets reduced. Those who are into metal casting say that the harder a material may become in heat treating, the less malleable and ductile it is, and the less malleable and softer it is, the less hard it turns out.