A new approach to numerical modeling of material fracture in cross wedge rolled parts

This study deals with the problem of modeling material fracture in the axial zone of a workpiece in cross wedge rolling (CWR) processes. A new approach to this problem is proposed, according to which improved accuracy of modeling can be ensured by precise determination of the critical value of material damage. It is shown that in CWR processes the critical damage value strongly depends on the forming temperature T and the applied reduction ratio δ. Experimental results are used to develop formulas for calculating the critical damage value of C45 steel, for different values of T (ranging from 900 °C to 1200 °C) and δ (ranging from 1.1 to 2.0). The study is conducted using three different criteria of ductile fracture (normalized Cockcroft-Latham, Pater et al., and Oyane et al.) and the Simufact.Forming software. The validation results show that the proposed material fracture prediction method determines accurately the location and size of axial cracks that can occur in CWR-produced parts.