Damage Investigation of the Preform Operations for the Production of Rings for Ring Rolling

Ring rolling is a bulk metal forming process that enables the production of seamless rings from a wide range of metallic materials and across a broad spectrum of dimensions. One prominent application of such rolled rings is the roller bearing ring, as employed by Schaeffler in its large‐scale bearing assemblies. During forming, microvoids originating from the cast billet are subject to the influence of successive forming operations, resulting in a characteristic void distribution within the final component. A thorough understanding of the relationship between the initial void state, process design, and void evolution is therefore essential for targeted process optimization. This study aims to quantify void evolution during the preforming operations (upsetting, pre‐piercing, and piercing) for two industrial process routes starting from different billet geometries. Metallographic characterization is combined with a two‐scale finite element simulation approach, coupling a macroscopic process simulation with representative volume element (RVE) analyses. The results show that a higher height‐to‐diameter ratio of the initial billet promotes more favorable void closure during upsetting, highlighting the potential of billet geometry selection to minimize residual void content in industrial pre‐ring production.