The resulting tensile residual stresses on the surface of cold full-forward extruded parts are unfavorable for the fatigue life of these parts. The final stress state is determined by the combination of two process stages: forming and ejection. This is due to the fact that the workpiece undergoes a second plastic deformation after forming during the ejection from the die. So far, literature is focusing mainly on the identification of the parameters affecting the residual stresses during the first stage. In the present paper, the attention is drawn to the ejection phase during cold extrusion of workpieces made out of the austenitic stainless steel AISI 316 L. First of all, a system consisting of an active die is presented. This technology allows the control of the applied pre-stress on the die during the process. It is experimentally and numerically demonstrated that a significant shift of the residual stress state in the near-surface region can be achieved. Even compressive axial and tangential residual stresses can be induced in this area. Also the limits of this system are numerically investigated. It is observed that a different deformation mechanism occurs above a certain pre-stress level. Finally, an analytical model is created and observations are presented relatively to the mechanisms that influence the plastic deformation during ejection.

冷的正向挤压零件表面上产生的拉伸残余应力不利于这些零件的疲劳寿命。最终应力状态由两个过程阶段的组合确定：成形和弹出。这是由于这样的事实，即工件在从模头顶出期间在成形之后经历第二塑性变形。到目前为止，文献主要集中在确定影响第一阶段残余应力的参数上。在本文中，注意力集中在由奥氏体不锈钢AISI 316 L制成的工件冷挤压过程中的顶出阶段。首先，提出了一个由活动模具组成的系统。这项技术可以控制过程中在模具上施加的预应力。实验和数值证明，可以在表面附近区域实现残余应力状态的显着变化。在此区域甚至可能会产生轴向和切向残余压缩应力。还对该系统的极限进行了数值研究。可以观察到，在一定的预应力水平以上会发生不同的变形机制。最后，创建了一个分析模型，并提出了与影响弹射过程中塑性变形的机制相关的观察结果。可以观察到，在一定的预应力水平以上会发生不同的变形机制。最后，创建了一个分析模型，并提出了与影响弹射过程中塑性变形的机制相关的观察结果。可以观察到，在一定的预应力水平以上会发生不同的变形机制。最后，创建了一个分析模型，并提出了与影响弹射过程中塑性变形的机制相关的观察结果。