Pendulum surface plastic deformation of cylindrical blanks

Abstract

The article discusses the features of kinematics of the working tool in form of circular sector during hardening by pendulum surface plastic deformation (SPD), which is carried out due to two successive processes – rolling and sliding in the contact zone of the deforming element with the blank. Forecasting of the possibility of its application for finishing and hardening processing of cylindrical parts such as shafts and axles is presented; the kinematic parameters of the pendulum SPD process in a rectangular coordinate system are described. Based on analysis of the components of motion types (rotational, translational, oscillatory) of the blank and tool, functions of the trajectory length, magnitude of the resulting velocity and acceleration were determined, which make it possible to control the technological parameters and modes of the pendulum SPD process. Reliability of the kinematic analysis is confirmed by the results of simulation with ANSYS  19.1 computer program. The results of dynamic modeling showed that under the same hardening conditions with a stationary position of the working tool and its opposite rotation with the blank, the intensity of temporary stresses increases by 10 % and 17 %, respectively, compared to the rolling scheme. With pendulum SPD, the intensity of temporary stresses increases sharply and reaches a maximum value (485 MPa), the distribution of which is uniform in comparison with other methods. In addition, regularity of the intensity distribution of temporary stresses over the cylinder depth is shown, where it is clear that in the case of SPD by sliding, the depth of plastic deformation h has a higher value compared to the SPD by rolling (by 1.5 – 2.3 times). Under the same hardening conditions, the highest value of the depth of the hardened zones is obtained with pendulum SPD (h = 2.8 mm), which leads to changes in the physical, mechanical and operational properties of the blank deeper surface layer.