Influencing damage in cold forging

Forming processes do not only bring materials into a desired shape, but also significantly determine their properties. One reason for this is the evolution of microscopic voids during the forming process. These are known as damage and influence the product performance of formed components.

The first and second funding periods (FP) addressed the fundamental mechanisms of damage as well as the influence of hydrostatic and deviatoric stress states.

In the third FP, the relationship between damage and component performance will be investigated. The focus lies on the effect of void closure and the quantification of uncertainties in product performance in order to predict the reliability of cold-forged parts. As a demonstrator, a pressure vessel will be manufactured under damage-controlled conditions. Furthermore, the transferability of the approach to additional materials will be examined, specifically the influence of damage on the aluminum alloy AA6082 and the austenitic stainless steel 1.4301 under warm forming conditions.

Gitschel, R., Gebhard, J., Korkolis, Y.P., Tekkaya, A.E., 2025. Isolating the effects of deviatoric and hydrostatic stress on damage evolution using cold extrusion experiments. International Journal of Solids and Structures. https://doi.org/10.1016/j.ijsolstr.2024.113205

Gitschel, R., Schulze, A., Tekkaya, A.E., 2023. Void nucleation, growth and closure in cold forging: An uncoupled modelling approach. Advances in Industrial and Manufacturing Engineering. https://doi.org/10.1016/j.aime.2023.100124

Gitschel, R., Hering, O., Schulze, A., Tekkaya, A.E., 2023. Controlling Damage Evolution in Geometrically Identical Cold Forged Parts by Counterpressure. Journal of Manufacturing Science and Engineering. https://doi.org/10.1115/1.4056266

Clausmeyer, T., Schowtjak, A., Gitschel, R., Hering, O., Ostwald, R., Tekkaya, A. E., Wang, S., Pavliuchenko, P., Lohmar, J., Hirt, G., 2020. Prediction of ductile damage in the process chain of caliber rolling and forward rod extrusion. 23rd International Conference on Material Forming. https://doi.org/10.1016/j.promfg.2020.04.201

Youtube-Link if process video is available: https://youtu.be/eb-LTMGTJmA