Induction hardening is a surface hardening process used to improve the material properties of components by inducing surface stresses with inductive heating. It is a process of heat treatment when a metal part is heated by induction to a predetermined temperature and then cooled rapidly. Induction hardening is used to increase the wear resistances and mechanical properties of the part. The induction hardening process involves introducing an alternating current through a coil of wound wire. This causes eddy currents to form on the surface of the workpiece, heating the part to the desired temperature. Once the part has been heated, it is cooled quickly by immersing it in oil or by directing a stream of oil onto the part surface.
Induction hardening has been used for many years to provide wear-resistant surfaces and improved mechanical properties. It is used in many industries, including automotive, aerospace, and power generation. Induction hardening is often used to harden the surfaces of turbine blades and drive train components. The process has also been used to harden bearings, fasteners, and other components for a variety of industrial applications.
Induction hardening has advanced significantly in recent years, with the development of modern computerized systems and better control over the heating and cooling processes. This has allowed induction hardening to be used in a wider range of applications and faster processing times. It has also enabled higher induction hardening accuracy and repeatability, and the use of advanced techniques such as laser hardening.
Induction hardening can also be used to improve the fatigue resistance of components by creating shallow compressive residual stresses on the surface. This technique, known as shot peening, is often used in the aerospace industry to increase the size of turbine blades. The process involves bombarding the part with a jet of air and small glass beads. This action causes small stress areas on the surface, forcing the grain structure of the surface material to deform and create compressive residual stresses.
Induction hardening is being increasingly used in combination with other heat treatments, such as tempering and stress relieving, to provide superior material properties. The combined treatments produce deeper, more uniform microstructures. This improves the performance of components in aggressive conditions and high-temperature applications.
Due to its wide range of applications and the potential for improved performance, induction hardening has become an important part of the heat treatment process. While it is a complex process, with many variables to consider, modern computer-controlled systems and improved techniques have made it simpler and more cost effective. As a result, induction hardening is becoming increasingly popular as a surface hardening method.
