Simulation methods for skew rolling

Abstract

Abstract A number of different rolling processes are summarized under the term skew rolling. The process variant investigated in this paper is an incremental flexible rolling process with kinematic forming of the geometry. Two sets of actively driven work rolls are used in a transverse rolling process to selectively reduce the diameter of a cylindrical workpiece to form circumferential grooves. Simultaneously, the excess material is pushed in axial direction, thereby forming a bulge that can be used to join e.g. a gear wheel onto an axle. Since this is done in a cold rolling process the positive influence of the induced residual compressive stress as well as strain hardening can be used to improve fatigue strength of the workpiece under cyclical loads. The authors discuss the advantages of this hybrid skew and cross rolling process and propose a simplified numerical model to quickly analyze process parameters like axial and radial work roll feed and the influence of initial stress profiles in the workpiece. The model uses a 2 ½ D axis-symmetric approach in LS-Dyna R10.1.0 with implicit solver. Additionally, preliminary results of first tests on rolled specimen from 42CrMo4 are briefly discussed.