Ferritic Nitrocarburizing (FNC): Demystifying the Process

The case hardening process known as ferritic nitrocarburizing (FNC) has seen increased interest recently in the transportation and mobility industries due its ability to impart strength and wear resistance to steels and cast irons with the added inherent benefit of less part distortion as compared to austenitic processes like carburizing and carbonitriding. There are numerous trademarked, standardized or proprietary nitriding and ferritic nitrocarburizing recipes and control methods used in various types of industrial furnaces. With the myriad process options available, it can be confusing for designers to understand which of these processes are best for their parts. To help, Surface Combustion has developed a new tool to predict the in-process composition of nitriding and ferritic nitrocarburizing atmospheres. The activities and potentials of carbon, nitrogen and oxygen can be found, leading to prediction of the associated equilibrium phase on the part surface. The theory behind the tool and the application of the tool to control nitriding and ferritic nitrocarburizing atmospheres will be discussed. An overview of different furnace designs and case studies of commercial installations will also be presented.