Ultrasonic Workpiece Surface Finishing Strengthen Organizational Structure And Performance Improvements

In order to improve the surface properties of the material, it proposed a series of surface treatments, such as shot peening, rolling and the like. Compared with these conventional surface treatment, ultrasonic finishing technology is a low-cost, easy handling, high efficiency approach. Currently the technology is still in the development stage of promotion, lack of basic theory and practical application in strengthening engineering research, has great potential in terms of improving the performance of the surface.Pure iron has good permeability, thermal conductivity, but the hardness, wear resistance and corrosion resistance is poor, limiting the application of iron, in order to improve the surface properties of pure iron, iron in the project to expand the scope of application to iron for the study, with an ultra deep microscopic observation of surface microstructure and the topography around the workpiece, it proved ultrasonic finishing "load shifting" effect, the workpiece surface to form a layer of plastic flow, the grain surface is stretched, surface coarse grain has been refined, finishing treatment improves the wear resistance under the workpiece in oil lubrication wear resistance and dry friction conditions.After finishing the number of ultrasonic machining the workpiece surface to form a layer of nano-grain refinement, grain boundary surface of the workpiece, and other non-equilibrium vacancy defects surge, high density of grain boundary diffusion of atoms can be used as a channel suitable for low-temperature diffusion studies, in order to further improve the wear resistance of the surface properties of pure iron, so that more permeable element proposed using nanoparticles Cr powder penetration element research, design a disc workpiece is immersed in the liquid inside the finishing element ultrasound penetration process, the workpiece is fixed sample holder, Cr powder was poured into ethanol suspension finishing, are easy to spread, without heating, easy handling, energy-saving features, with added Cr super depth of field microscope suspension before and after processing of the workpiece and the topography microstructure was observed, adding Cr powder suspension workpiece surface fluctuations small three-dimensional morphology, rheological surface layer of small thickness, more uniform grain refinement to improve the maximum residual compressive stress of the workpiece surface.To further iron ultrasonic finishing element diffusion studies, combined with the proliferation of atomic theory, ultrasonic finishing process does not add coolant to the machining head ultrasound frequency impact surface, the gradual accumulation of energy, much of the energy as heat transfer, increased surface temperature, suitable for diffusion studies, the choice of nano Ni, Cr powder is mixed element diffusion source, Cr, Ni powder contrast, XRD diffraction peak pattern found Ni, iron proof ultrasonic finishing element diffusion processing can be realized by means of friction and wear tester analysis add Cr, Ni on the wear resistance of the workpiece, adding Cr, Ni powder after the workpiece wear resistance increased at the high load, the friction coefficient of not less than adding Cr, Ni powder workpiece friction coefficient, wear resistance improved significantly.