| How can the hardness of a workpiece be adjusted?

The desired hardness of a workpiece is determined based on its intended functionality. If a workpiece requires a different level of hardness, heat treatment can be employed to modify its specifications. Various heat treatment methods are utilized to meet specific requirements, including:


To enhance the hardness of carbon steel or alloy steel workpieces, quenching is commonly employed. This process involves heating the workpiece above its critical temperature and holding it for a specified duration. Subsequently, the workpiece is rapidly cooled using water, oil, or air to complete the quenching process. While quenching increases hardness, it may also reduce the ductility of the workpiece.


Tempering is a process employed to enhance the toughness of carbon steel or alloy steel tooling or springs. In cases where parts exhibit excessive hardness or become overly brittle after quenching, tempering can be applied to reduce hardness and increase ductility. This involves heating the workpiece to a temperature below its critical point and gradually cooling it to a lower temperature. This controlled cooling process helps achieve the desired balance between hardness and ductility.


Annealing, similar to tempering, is a heat treatment process that can modify the properties of a workpiece to reduce hardness and increase ductility. By subjecting the metal workpiece to an appropriate heating temperature, the atoms within the metal attain a more balanced state. Following the heating stage, the workpiece is typically allowed to cool slowly in an oven, facilitating recrystallization and grain growth. For components made of carbon steel or alloy steel, particularly terminal or connector spare parts used in crimping, annealing heat treatment may be necessary.

4.case hardening

Numerous heat treatment methods exist for selectively increasing the hardness of a workpiece. One such method is case hardening, which involves enhancing the stiffness of the outer layer of a carbon steel or alloy steel workpiece while maintaining the softness of its core for improved ductility. This results in a hardened surface that offers enhanced durability and wear resistance. However, it is important to note that the hardened surface becomes unsuitable for further machining operations. Therefore, case hardening is typically performed after the completion of the CNC machining process on the workpiece.