Non-contact deformation with reversible surface plastic deformation

The article considers non-contact deformation during surface plastic deformation based on the reverse rotation of the deforming tool. Using software for 3D design (Solid work 2019) and computational modeling (Ansys workbench 19.2), calculations were made to determine the size of an elastic-plastic wave depending on the main parameters of reverse surface plastic deformation (SPD) and the physical and mechanical properties of the material. The stress state in elastoplastic waves generated in the direction of feed ( A 1) and in the direction of the main movement ( A 2) is also established. It has been established that the linear dimensions of elastoplastic waves reach a maximum at a preload value of t = 0.4 mm. The main parameters of the reversible PPD, which characterize the kinematics of the working tool (reverse speed of the working tool, the speed of the workpiece, the initial angle of the working tool and the amplitude of the angle of the reverse rotation of the working tool) have a significant impact on the change in the size of the elastoplastic wave in the direction of the longitudinal feed and slightly affect the change in the size of the elastic-plastic wave in the direction of the main movement. The change in the stress state of the surface layer is shown depending on the physical and mechanical properties of the material: large sizes of the elastic-plastic wave during elastic-plastic deformation are formed in the material with a reduced yield strength and elastic modulus. It was also found that the larger the size of the elastic-plastic wave, the higher the maximum tensile stresses at their vertices. The resulting stress state of the wave allows us to conclude that maximum tensile stresses are formed at their tops, the value of which reaches 202-271 MPa (2,4-3,2 times less than the ultimate strength of the material), which practically does not cause strength failure hardened surfaces.