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

高负荷的钢制复杂长件通常分几个阶段进行闪光锻造。以曲轴为例，在最近完成的研究项目中，证明了这些零件的闭式锻造在生产中提高资源效率的潜力。开发了一种无缺陷的四级曲轴二次成形销和凸缘两缸曲轴。分楔横轧、侧向挤压、多向锻造和精密锻造四个阶段。多向锻造已被认为是实现销轴轴承与主轴承在闭式锻造过程中偏置的关键步骤。在没有侧向挤压的情况下，将工艺步骤缩短为三个步骤，部分地造成了褶皱和飞边的形成。这些缺陷的原因还没有确定。缺乏对原因的了解，妨碍了适当工艺的可靠设计。因此，确定楔横轧和多向锻造的几何形状与褶皱和飞边发展的关系，对于无飞边锻造复杂的锻件是至关重要的。这对于缩短锻造顺序是必要的。为了在缩短的工艺链中无闪烁地锻造复杂的锻件，本项目的目的是研究楔横轧和多向锻造之间的关系。主要关注点在于几何方面。通用的数学模型应便于设计楔横轧预制件的几何形状和多向锻造工具的成形元件。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。没有主轴承偏移量的轴和曲轴(有偏移量)都被考虑在内，以便能够将应用转移到更广泛种类的复杂长零件上。

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.