In this paper, a new forging system was developed and a new complex methodology was tested for the analysis of the closure of voids. The effective geometric shapes of anvils and optimal the forging parameters has been determined. A new cogging process provided a complete closure of voids, which was confirmed by experimental tests. The effect of the reduction ratio, original anvil shape, forging ratio and the location and size of introduced voids on the efficiency of void closure during the multi-transition cogging process was assessed. Moreover, the following were used for the evaluation of void closure: the hydrostatic stress around voids, stress triaxiality, effective strain around voids, and the critical reduction ratio. Numerical examinations were performed using the finite element method (FEM) for the three-dimensional forging process at elevated temperature. Computer simulations of the cogging process under investigation were carried out using a program DEFORM-3D, and selected simulation results were compared with experimental test results. Void reduction predictions obtained from the FEM analysis were in good agreement with the experimental findings. The test results are supplemented with the prediction of crack formation in the zone of existing voids and within the forging volume during the multi-transition cogging process.

本文开发了一种新的锻造系统，并测试了一种新的复杂方法来分析空隙闭合。砧座的有效几何形状和最佳锻造参数已经确定。新的开槽工艺完全封闭了空隙，这一点已通过实验测试得到证实。评估了多过渡开槽过程中的压下比、原始砧形状、锻造比以及引入空隙的位置和尺寸对空隙闭合效率的影响。此外，以下用于评估孔隙闭合：孔隙周围的静水应力、应力三轴性、孔隙周围的有效应变以及临界收缩率。使用有限元法（FEM）对高温下的三维锻造过程进行了数值检查。使用DEFORM-3D程序对所研究的开槽过程进行计算机模拟，并将选定的模拟结果与实验测试结果进行比较。从有限元分析获得的空洞减少预测与实验结果非常吻合。测试结果补充了多过渡开槽过程中现有空隙区域和锻件体积内裂纹形成的预测。