Formability analysis of bearing ring produced by short-flow warm extrusion processing

Abstract

Bearing rings are the most common used machine parts. It is of great significance to reduce the processing flow of bearing rings for saving energy and material, increasing productivity. In this work, one step warm extrusion processing using ring blank as preform was proposed to form bearing ring which possesses upper and lower rings. The upper and lower rings are formed by materials reverse and forward flow during warm extrusion, respectively, and the ratio of materials reverse flow amount to forward flow amount (RRFA) determines the formability of bearing rings. In order to process bearing rings at optimum RRFA at which the upper and lower rings can be simultaneously formed, finite element models for the warm extrusion processing were established based on DEFORM-3D software. The effect of extrusion ratio, round corner radius of extrusion die, extrusion temperature, friction coefficient on the flow rules of materials was analyzed by the developed finite element models. The results show that small extrusion ratio (i.e. small outer diameter of ring blank) and large round corner radius of extrusion die enhance the material flowing into lower ring and facilitate the forming of lower ring. Extrusion temperature and friction coefficient have little effect on RRFA. Comprehensively considering the flow rules of materials, the well-formed bearing rings can be obtained when extrusion ratio is 2.33, round corner radius of extrusion die is 1.5, extrusion temperature is 700-800 °C.