Contact Pressure Profiles in Axisymmetric Compression Considering Friction and Geometrical Factors

Contact pressures in open die forging of axisymmetric parts are mainly influenced by friction and billet geometry through the shape factor. In this work, a FE model has been developed for analyzing the compression of axisymmetric billets, assuming different friction conditions and shape factors of the workpiece in order to evaluate the contact pressures behaviour under compression and to determine general trends. A constant friction factor law is assumed, m, and the shape factor is determined as the ratio between the height of the workpiece and its diameter, H/D. Additionally, results are compared with those obtained by the SM method to validate the numerical model. The results presented in this paper demonstrate that the area of highest wear is located in different positions depending on the original geometry of the workpiece, so this information could be considered as a useful guidance when designing dies in more complex compression processes as well as in other recent related processes such as multi-material forming.