The Basics Of Induction Hardening Metal Parts And Components
While often used on steel, induction hardening can also be used on a wide range of different alloys. It is used across all industries and is an ideal option when specific areas or features on a part or component need to be hardened without the same process used across all surfaces.
During the process, only the parts that are subjected to the induction process have the surface change. As this is online done on the surface layers, there is no internal stress built up in the part or component as is more common with other types of heat treatment using direct heating methods.
There are two parts of the process that include induction heating and then quenching. The induction heating prepares the metal to go through a martensitic transformation during the quenching stage, which makes the surface area of the part harder but also slightly more brittle.
There is no direct contact of heat with the surface of the part in induction hardening. Instead, an electromagnetic process is used to excite the molecules in a conductive workpiece that are exposed to the magnetic field in the area to be treated.
The level of the change in the surface metal can be controlled by the frequency of the alternating field as well as the power density, the time of the process, the current generated and the material thickness. The induction hardening is specifically designed for the given part based on these factors.
Once the induction stage is completed for the desired results, it then quenched in a specific type of material. This may be water, a polymer-based material or oil. This non-contact heating and then quenching creates a surface layer that is harder than the original layer of metal or alloy.
It is a fast process that does not have a time where the workpiece has to be held at a specific temperature. With the use of experienced operators and carefully designed processes, this can provide surface hardening to extremely tight tolerances that offer high levels of fatigue resistance as well as wear resistance even in the most challenging types of environments and applications.