There are many different heat treatments that can be used with different types of metals and alloys to create the desired hardening effects. Many of these are only used for complete parts and components, which some, like induction hardening, can be used for just specific areas on a part or component.
The basics of induction hardening have been used since the early part of the 1800s. It involves heating metal through the use of induction heating. This is a non contact type of heating that uses electromagnetic fields to generate a current and create the energy needed to create the temperature increase.
As the steel alloy, which has to be electrically conductive and magnetic, is heated to the specific temperate just under the surface layer, it is quickly quenched. This quenching can be done by a variety of liquids including polymer-based liquids, water or oil. This quenching changes the surface to create a martensitic structure just at the surface. The rest of the workpiece is not altered in any way, which makes this important for many types of applications.
With new technology, induction hardening can be completed through automated systems. This includes the induction heating and subsequent quenching of multiple small parts at a time or even with extremely large parts such as axles, drive shafts, and other types of cylindrical as well as flat surfaced parts and components.
The application of the electromagnetic field to specific areas of the part and subsequent quenching of that area allows for very specific surface treatments that can be designed to meet industry or customer specifications and requirements.
The advantages to this process include creating a surface that is very resistant to wear and fatigue. The process itself is also fast, so large volume orders can be quickly processed, lowering the overall cost.