Hardenings: Selective hardenings can be done by flame, induction, laser or electron beam.
High Energy Treatments: Common high energy treatments include ion implantation, laser glazing/fusion, and electron beam treatment.
Thin Diffusion Treatments: Thin diffusion processes include Ferritic-nitrocarb, boronizing, and other high temperature reaction processes, e.g., TiC, VC.
Heavy Diffusion Treatments: Heavy diffusion processes include carburizing, nitriding, and carbonitriding.
Special Treatments: Some special treatments, such as cryo, magnetic, and sonic treatments, affect not only the surfaces but also the bulk materials.