Effect of textures fabricated by ultrasonic surface rolling on dry friction and wear properties of GCr15 steel

Linear textures and cross textures with different processing stepovers were fabricated on the surface of GCr15 steel by ultrasonic surface rolling processing (USRP). The effects of texture shape and processing stepover on the dry friction and wear performance of the samples were investigated using a ball-and-disk friction tribometer. The results showed that all the USRP texturing samples had lower friction coefficients and wear rates than those of the substrate sample under dry friction conditions. The best tribological performance was achieved at the stepover of 150 μm for linear textures and 250 μm for cross textures. For two shapes of textures with the same stepover, the linear texture had better wear resistance and the cross texture had better friction reduction. The texture shape and processing stepover influenced the texture height and the strengthening effect, which in turn affected the tribological properties of the samples. The improvement in friction and wear performance by ultrasonic rolling texturing was attributed to the synergistic effect of the strengthened substrate, reduced actual contact area, and entrapment of wear debris.