Simulation And Technology Research On Ultrasonic Impact Peening Of Micro-Texture On Stainless Steel Surface

Ultrasonic impact peening(UIP)is a widely used cold surface treatment technology,which is generally used to improve the fatigue life of welded metal parts and reduce residual stress.The high-frequency impact of the high-energy impact head on the surface of the workpiece can eliminate the harmful residual tensile stress on the surface of the workpiece and introduce residual compressive stress,thereby improving the mechanical properties of the workpiece.In addition,by increasing the impact amplitude,permanent plastic deformation can be generated on the processed surface,and at the same time,the precision motion table is used to control the processing path,which is expected to achieve high-precision functional surface microstructure processing.However,it is unclear about the deformation and stress changes of materials during ultrasonic impact processing.Revealing the related mechanisms of material deformation and stress changes is of great significance for exploring the feasibility of ultrasonic impact peening of microstructures.This paper proposes a processing method that uses ultrasonic impact processing to prepare microtextures on the surface of stainless steel.Through the combination of theory,simulation and experiment,the material deformation and stress distribution mechanism of ultrasonic impact peening microstructures are obtained.First of all,the ultrasonic impact peening process is theoretically analyzed to obtain the expression formula describing the micro-textured surface morphology and contact stress.The ultrasonic impact finite element simulation model was established by ABAQUS software to numerically analyze the micro-texturing process on the surface of 316 L stainless steel.Then,an ultrasonic impact processing experimental device was built to perform the indentation experiment and the single groove micro-textured ultrasonic impact processing experiment.Using the ultrasonic impact finite element simulation model to study the effect of different pre-pressure,impact ball amplitude and feed speed on the groove shape,surface residual stress distribution,depth residual stress distribution and material hardness of the workpiece after ultrasonic impact processing law.Finally,the optimized process parameters of 316 L stainless steel surface micro-textured ultrasonic impact processing were obtained.Ultrasonic impact and elliptical vibration diamond cutting technology were used to process the micro-texture of the groove array of the same shape on the surface of stainless steel.Then,the friction properties of the stainless steel micro-textured surfaces obtained by the two processing methods were compared.Finally,two-dimensional finite element models of ultrasonic impact and elliptical vibration diamond cutting were established to study the reasons for the different friction properties of the samples obtained by the two processing methods.In summary,the method of ultrasonic impact processing of the micro-texture of the stainless steel surface grooves has low equipment cost,and the processed groove array micro-texture surface is smooth,consistent,smooth transition,and good friction reduction performance.Ultrasonic impact method is superior to stainless steel surface micro-texture processing.The work in this paper has certain guiding significance for the preparation of fine microtexture on stainless steel at low cost using mature ultrasonic impact processing technology.