The Scuffing Resistance of the Nitrocarburized and Carburized Steel

A ring on block lubricated sliding wear test was used to study severe adhesive wear or scuffing between cam and cam-follower materials. The scuffing resistance was measured at constant 4,85 m/s disk velocity. DIN 100Cr6 quenched and tempered rings were tested against DIN 16MnCr5 blocks treated to obtain two different surface conditions: a) carburized;, b) carburized and nitrocarburized with predominantly carbonitride layer. The worn surfaces were characterized using scanning electronic microscopy (SEM). The phases present at the nitrocarburized layer were characterized using GDS. The role of the layer on the scuffing resistance was evaluated. The nitrocarburized specimens had better scuffing resistance than carburized one. The friction power intensity criterion was used to define the capacity of the material to resist to scuffing. A low FPI (friction power intensity) has a high scuffing resistance.