Application of Smoothing Rollers in Processes Finishing–Strengthening Treatment of Shafts’ SPD

Abstract

The paper proposes a method for improving the quality of the surface of shafts in traditional strengthening treatment by surface plastic deformation (SPD) by using additional smoothing rollers having a small curvature of the working profile in axial section. On the basis of the solution of the elastoplastic contact problem, an analytical dependence is obtained for determining the radius of curvature of the profile of smoothing rollers. The dependences of changes in hardness and yield strength over the depth of the hardened surface layer of steel shafts are experimentally established, and regression equations describing the nature of these changes are given. As an example, the curves of hardness distribution in depth of the plastically deformed shaft layer with a diameter of 50 mm from normalized steel 45 subjected to rolling treatment with toroidal rollers by various forces are presented. Also, this paper presents the results of testing the effectiveness of the use of smoothing rollers in strengthening the roll running toroidal rollers with a roller of a diameter of 40 mm for shafts with materials steel 45, 50, and steel 40X. The authors experimentally confirmed the high efficiency of the proposed methodology in the organization of the technological process of finishing and hardening treatment of shafts, which allows one to significantly improve the quality of their surface.