Process Simplification of Multi-Stage Forging for the Outer Race of a CV Joint

Abstract

Constant velocity (CV) joint with six inner ball grooves has been conventionally produced by a multi-stage warm forging process that includes forward extrusion, upsetting, backward extrusions, necking, ironing, and sizing. In this study, multi-stage cold forging is presented with four simplified stages of forward extrusion, modified upsetting, backward extrusion, and combined necking–ironing–sizing. A three-dimensional numerical simulation is performed to ensure the appropriateness of the proposed process, and experimental investigations are carried out using spheroidized and phosphophyllite-coated SCr420H billet material. It is shown that the proposed multi-stage cold forging process could be successfully applied to the production of the outer race.