Erosion and wear behavior of nitrocarburized DC53 tool steel

The influence of nitrocarburizing holding time on the slurry erosion and wear behavior of DC53 tool steel has been studied. DC53 tool steel was nitrocarburized at 570°C for 2, 4, and 6h. The microstructures and hardnesses of the nitrocarburized coatings were analyzed. The erosion-behavior test was conducted using a slurry jet at different impinging angles. Wear behavior was examined on a block-on-roller wear tester under unlubricated conditions. The surface roughness was also measured. The results show that white compound layers are composed mainly of ɛ-nitride (Fe3N) and a small amount of γ′-nitride (Fe4N). The nitrocarburizing treatment not only increases the hardness but also decreases the friction coefficient of the specimen. Furthermore, the erosion rate and the wear loss of the nitrocarburized specimen decrease. The anti-wear property of the nitrocarburized specimen is found to relate to the increase in the depth of the diffusion zone. The maximum erosion rate appears at an impinging angle of 30° for all specimens. In this condition, plough grooves and cutting lips appear in the eroded surface; however, the traces of erosion on the untreated specimen are wider and deeper. After nitrocarburizing, the severe adhesive wear is replaced by a much milder abrasive wear. As the nitrocarburizing holding time increases the erosion rate decrease, but the wear properties including the wear loss, friction coefficient, wear mechanism and the width of the abrasion grooves do not change significantly.