Research On The Effect Of Ultrasonic Surface Rolling Extrusion Parameters On Friction And Wear Properties Of 45 Steel

Ultrasonic Surface Rolling Extrusion(USRE)is a new type of surface strengthening method based on elasto-plastic deformation,which utilizes the coupling of ultrasonic mechanical vibration and static rolling to process the surface,to achieve the surface quality improvement of metal materials and improve its overall performance.USRE has a number of process parameters such as spindle speed,infeed,static pressure,output amplitude,processing times and vibration frequency.Processing of materials under different process parameters will inevitably lead to different surface quality,which will affect Material properties.In this paper,the quenched and tempered 45 steels were processed by milligram energy HK30 C series ultrasonic rolling equipment and ordinary horizontal lathes.The surface characteristics of the USRE specimens were analysed by metallographic sample preparation equipment,metallographic microscope,Surface roughness measuring instrument,microhardness tester,and an X-ray powder diffractometer.The USRE specimens with different static pressures,output amplitudes,and processing times were subjected to a wear test by MMG-10 type high-temperature friction and wear tester.The wear and abrasion weight,friction factor and surface micro-topography of the USRE specimens were compared and analyzed by optical reading analysis balance,related software and scanning electron microscope.The wear resistance of the material was evaluated.The effect of the USRE process parameters on the wear resistance of the quenched and tempered 45 steel was studied.The main results of this paper are as follows:(1)When other process parameters are constant,the smaller the spindle rotation speed or infeed,the greater the surface roughness and surface hardness of the material,and the surface residual compressive stress has increased in various degrees.Therefore,in the actual processing to ensure the accuracy of the machine tool and processing efficiency under the premise of the lowest possible choice of spindle speed and infeed.(2)When other process parameters are constant,the static pressure is 300 N,the material wear amount and friction factor are the lowest,the grain refinement is the highest,and the material wear resistance performance is the best.Static pressure is too small to increase the material's wear resistance.Excessive static pressure will deteriorate the surface properties and increase the grain size of the material,which will reduce the wear resistance of the material.Therefore,in the actual processing,the static pressure should be maintained at about 300 N as much as possible.(3)When other process parameters are constant,the output amplitude is 8?m,the material wear amount and friction factor are the lowest,the grain refinement degree is the highest,and the material wear resistance performance is the best.The output amplitude has a linear relationship with the surface roughness and hardness of the material,but the impact on the residual stress is not much different.When the output amplitude is less than or greater than 8?m,the wear resistance of the material will be reduced,but the degree of influence of the latter is much higher than the former.Therefore,the output amplitude should be 8?m as much as possible in actual machining,otherwise the output amplitude of the smaller parameter is preferred.(4)The processing times and output amplitude have similar effects on the wear resistance of the material.The materials processed six times have the highest wear and friction factors,and the highest degree of grain refinement.The wear resistance is the best.Therefore,in the actual processing as much as possible 6 times,in the increase of work efficiency,can reduce the number of processing properly,but it is best not less than 3 times.