What does hardening refer to in machining?

Hardening in machining specifically refers to the process used to increase a material's hardness, typically through thermal or mechanical means. This process is primarily applied to metals, particularly steel, to enhance their strength and wear resistance.

When metals undergo hardening, techniques such as quenching or deformation are employed. For instance, the quenching process involves heating the steel to a high temperature and then rapidly cooling it, which alters the microstructure of the material, resulting in increased hardness. Further methods, like case hardening, involve creating a hardened layer on the surface of a material while maintaining a softer interior.

This increase in hardness allows machined parts to withstand greater stresses, prolong their service life, and maintain dimensional accuracy over extended use. Thus, the correct understanding of hardening is crucial for machinists in selecting appropriate processes for parts that require high wear resistance and strength.