Influence of multiple ultrasonic impact treatments on surface roughness and wear performance of SUS301 steel

- An easy mechanical surface enhancement technique based on ultrasonic vibration was described.
- The roughness and hardness of SUS301 steel were respectively reduced and increased by this technique.
- The evolution of surface morphology was analyzed over multiple passes.
- This technique increased the wear resistance of SUS301 steel.

This paper described an easy mechanical surface enhancement technique based on ultrasonic vibration, namely ultrasonic impact treatment (UIT). The effects of multiple ultrasonic impact treatments (UITs) on the surface properties of SUS301 steel were investigated using an optical microscope, a step profiler, a non-contact optical profiler, a micro hardness testing machine, X-ray diffraction (XRD), and a pin-on-disk tribotester. The results showed the effects of surface smoothing and hardening on the wear performance. An increase in the number of UITs resulted in a lower roughness and higher hardness. After three UITs, the surface roughness decreased from 0.694 to 0.112 μm, and the hardness increased from 257.32 to 428.38 HV. The evolution of surface morphology was also analyzed in detail over multiple UITs. Moreover, the volume fraction of plastic deformation-induced martensite increased with the number of UITs of the surface. The samples treated three passes showed better wear resistance than untreated samples under dry sliding conditions.