Abstract:The commercially pure titanium welded joints were treated with a selfdeveloped ultrasonic impactrolling treatment device.The effects of different process parameters on the surface roughness,hardness of the commercially pure titanium welded joints were studied.It is found that the surface grain size of the material is refined to nanometer level and the thickness of the deformation layer is about 320 μm,the surface roughness of the sample is increased,and the hardness of the sample is increased from HV1466 to HV3128,1134% higher than the untreated material.Dry friction and wear tests were conducted on the ultrasonic impactrolling treatment pure titanium welded joints by using a balldisk structure tester,the worn surface morphology was observed by scanning electron microscopy.The results show that that the friction coefficient and the wear loss of the ultrasonic impactrolling treatment specimens are reduced compared to the untreated specimens,and reach the minimum value at the impact current of 1 A and the impact time of 9 min.The ultrasonic impactrolling treatment specimens have a shallower wear scar and a smoother wear surface,indicating the ultrasonic impactrolling treatment can significantly improve the friction and wear properties of commercially pure titanium welded joints.