This specification covers the engineering requirements for producing a continuous thin epsilon iron carbonitride compound layer on parts by means of a gaseous, low-temperature process, and properties of the case.This process has been used typically to increase wear resistance and fatigue and to improve corrosion resistance on ferrous metals, such as carbon, low-alloy, and tool steels, and cast irons, but usage is not limited to such applications. This process can be selectively applied to wear areas of the component.