ProKomb - Process combination of cross wedge rolling with multi-directional forming

高强度、复杂的长型钢件通常分几个阶段锻造。在最近完成的以曲轴为例的研究项目中，证明了这些零件的无闪锻在提高生产资源效率方面的潜力。一种无缺陷的，四级序列已开发的双缸曲轴与二次形式元件销和法兰。加工阶段有楔横轧、侧向挤压、多向锻造和精密锻造。为了实现销轴承与主轴承在无闪锻过程中的偏移，多向锻造已被确定为必不可少的步骤。将工艺步骤缩短为三个步骤，没有侧挤压，部分造成了褶皱和闪光的形成。这些缺陷的原因还没有被确定。缺乏对原因的了解妨碍了对适当过程的可靠设计。因此，为了实现复杂锻件的无闪边锻造，确定楔横轧几何形状与多向锻件在褶皱和闪边发展方面的相关性是必要的。这对于缩短锻造顺序是必要的。为了在短工艺链中无火花锻造复杂锻件，本项目的目的是研究楔横轧与多向锻造之间的关系。主要的焦点在于几何方面。一个通用的数学模型将有助于设计楔横轧预制件的几何形状和多向锻件的成形元件。该模型的边界条件应使用成形过程的有限元模拟来确定，并应在锻造试验中进行验证。轴没有偏移的主轴承和曲轴（与偏移）被考虑在内，能够转移应用到更广泛的各种复杂的长零件。

High-duty complicated long parts made of steel are usually forged with flash in several stages. The potential of flashless forging of these parts to increase the resource efficiency in production has been demonstrated in recently completed research projects using crankshafts as example. A defect-free, four-stage sequence has been developed for a two-cylinder crankshaft with secondary form elements pin and flange. The stages are cross-wedge rolling, lateral extrusion, multi-directional forging and precision forging. The multi-directional forging has been identified as an essential step in order to realize an offset between pin bearings and main bearings in a flashless forging operation. The shortening of the process steps to three steps without the lateral extrusion partially caused a formation of folds and flash. The causes of these defects have not been identified, yet. The absence of knowledge about the causes prevents a reliable design of the appropriate processes. To identify the dependency between the geometry of the cross wedge rolling and the multi-directional forging concerning the development of folds and flash is therefore essential in order to forge complicated forgings flashlessly. This is necessary for a shortened forging sequence.In order to forge complicated forgings flashlessly in a shortened process chain, the aim of the project is to investigate the relationship between cross-wedge rolling and multi-directional forging. The main focus lies on the geometrical aspects. A universal mathematical model shall facilitate the design of the geometry of cross-wedge rolling preforms and the forming elements of the multi-directional forging tool. The boundary conditions of the model shall be determined using finite element simulations of the forming processes and shall be verified in forging trials. Shafts without an offset of the main bearing and crankshafts (with the offset) are taken into account to be able to transfer the application to a wider variety of complicated long parts.