Influencing the Evolution of Damage in Cold Extrusion

During metal forming, voids inside the material develop and grow on a microscopic level. These voids are referred to as ductile damage and influence the performance of manufactured components during service life. In the first funding period of the project, it was demonstrated that damage-controlled cold forging processes can produce components with increased product performance. For this purpose, the hydrostatic stress state was specifically varied during the forming process. The aim of the second funding period is to extend this proof to the influence of a change in the deviatoric stress state and the influence of heat treatments between forming steps or after forming. These influences will first be investigated in basic experiments before application-oriented cold-forged parts are examined, which are produced in several stages using the forming processes backward can extrusion, forward hollow extrusion, ironing, upsetting and, if necessary, with additional heat treatment (see figure).