Control of forming behavior by inhomogeneous heating of semi-finished products during cross-wedge rolling

本研究建议处理的成形行为的控制与局部可变的流动应力的帮助下，通过不均匀加热的半成品在楔横轧。通过不均匀地加热半成品，例如在半温区和温区，材料的流动特性可以适应楔横轧模具。这将增加工艺稳定性并防止轧制缺陷。在楔横轧过程中，可能会出现不同的轧制缺陷，这些缺陷会影响沿着工艺链的部件质量。例如，在楔横轧过程中可能出现空隙、沿半成品的纵向轴线的沿着内部裂纹、内部褶皱、表面缺陷、压痕不足、鱼嘴效应或过轧。轧制缺陷的一个原因是由于例如在楔横轧工艺期间半成品的滑移或不均匀扭转而导致的工艺稳定性不足。在楔横轧过程中，滑移或扭转是由局部不同的流动路径引起的。楔形区域中的材料流动明显多于楔形外部区域中的材料流动。例如，这导致不同的扭转。目前，锯齿被引入到楔横轧工具中，例如以减少滑移。然而，大量的锯齿在楔横轧过程中留下表面缺陷，并且只能用于没有功能表面的区域。不均匀加热可以通过减少模具中的锯齿数量来减少表面缺陷，并且还可以降低模具成本。此外，不均匀加热还导致半成品的局部结垢减少并改善表面质量。楔横轧半成品不均匀加热的加热策略目前还没有研究。根据初步调查结果，本研究项目的工作假设是，半成品的不均匀加热会使楔横轧工艺更加稳定，质量更有保证。本研究的目的是确定不均匀的半成品加热对楔横轧过程的影响，以提高轧制质量和工艺稳定性。在特别不均匀加热的半成品中，不同的流动应力将被用于特别影响成形行为，从而提高轧制质量。轧制质量的评估方面的鱼嘴深度，表面缺陷，内部缺陷的概率和扭转。通过观察半成品的滑移来评估工艺稳定性。

The present research proposal deals with the control of the forming behavior with the aid of locally variable flow stresses through inhomogeneous heating of the semi-finished product during cross wedge rolling. By heating the semi-finished product inhomogeneously, e.g. in half-warm and warm areas, the flow properties of the material can be adapted to the cross wedge rolling die. This should increase process stability and prevent rolling defects. During the cross-wedge rolling process, different rolling defects can occur that influence the component quality along the process chain. For example, voids, internal cracks along the longitudinal axis of the semi-finished product, internal wrinkles, surface defects, insufficient impressions, fishmouth effects or overrolling can occur during cross wedge rolling. One cause of rolling defects is insufficient process stability due to, for example, slippage or uneven torsion of the semi-finished product during the cross-wedge rolling process. Slippage or torsion results from the locally different flow paths during the cross wedge rolling process. The material in the area of the wedge flows significantly more than in the area outside the wedge. This results in different torsions, for example. Currently, serrations are introduced into the cross wedge rolling tool, for example to reduce slippage. However, the large number of serrations leave surface defects during the cross wedge rolling process and can only be used in areas without functional surfaces. Inhomogeneous heating can reduce the surface defects, by reducing the number of serrations in the die and additionally reduce die costs. In addition, inhomogeneous heating also leads to a local reduction in scaling of the semi-finished product and improves surface quality. The heating strategy of inhomogeneous heating of semi-finished products for cross wedge rolling has not yet been the subject of research. From the preliminary investigations carried out, the working hypothesis of this research project is that inhomogeneous heating of semi-finished products leads to a more process-stable and quality-assured cross wedge rolling process. The aim of this research project is to determine the influence of inhomogeneous semi-finished product heating on the cross wedge rolling process in order to increase rolling quality and process stability. Different flow stresses in specifically inhomogeneously heated semi-finished products are to be used to specifically influence the forming behavior and thus increase the rolling quality. The rolling quality is assessed in terms of fishmouth depth, surface defects, internal defect probabilities and torsion. Process stability is assessed by looking at the slippage of the semi-finished product.