The use of heat treated parts and components is required in many different industries and applications. Heat treating is used to change the physical properties of a metal part or component, which can include making metals softer and more malleable or making then harder and more durable.
In general, heat treatments are only designed to change the surface of the metal part or component. For changes to the deeper structure of the material, such as required in stress relief, different types of heating and cooling methods are used.
A quenching heat treatment involves the same technologies as the methods described above, but instead of the slow cooling that allows a more significant molecular change throughout the entire part or component, quenching is used to offer a rapid cooling process.
The Basics
There are many different choices in quenching heat treatment options, and the specific type of metal or alloy in the component determines the option that is best. The most traditional method of quenching is to plunge the heated part into the water, which can be fresh water or salt water. Both types of water produce different results, but they are both good options based on the amount of heat the liquid can absorb, typically resulting in a hard surface layer.
For a slightly slower cooling process in a quenching heat treatment, various oils can be used. This allows a greater change in the microstructure of the metal, resulting in lower level hardness to the surface, which may be significant based on the specific requirements for the part.
There is also the option to use specialized polymers, gases, and even salts. Each of these options provides a different quenching rate, or cooling rate, that directly impacts the surface properties of the metal or alloy on the component.
