Heat treatment can be applied to many metal alloys to significantly improve key physical properties (e.g. hardness, strength or machinability). These changes are due to alterations in the microstructure and sometimes in the chemical composition of the material.

These treatments involve heating the metal alloy to (usually) extreme temperatures and then cooling it under controlled conditions. The certain temperature to which the material is heated, the time for which it is held at that temperature, and the rate of cooling can greatly affect the final physical properties of the metal alloy.

In this article, we review the heat treatments associated with the most commonly used metal alloys in CNC machining. By describing how these processes affect the final part properties, this article will help you select the right material for your application.

After CNC Machining: Some heat treatments significantly increase the hardness of the material or are used as a finishing step after forming. In these cases, the heat treatment is performed after CNC machining because the high hardness reduces the machinability of the material. For example, this is standard practice when CNC machining tool steel parts.