complementary machining - simulation based analysis of a mechanical surface treatment integrated in a machining process for the intended formation of nanocrystalline surface layers

本研究项目的目的是将工艺策略互补加工应用于技术相关的生产工艺车削。旋转对称部件，如由调质钢AISI 4140(42CrMo4)制成的轴，通常代表高应力部件，其表面在加工后进行进一步处理，以确保所需的性能。部件特性，如用于优化部件的摩擦学行为或使用寿命的地形，是技术上相关的目标值。零件特性通常是通过昂贵的后期加工工艺实现的，如深轧或锤击。互补式加工是在不更换刀具的情况下，通过反转切割方向，用加工工具对零件进行表面处理，在加工后进行表面处理。由于极负的前角，导致构件表层产生塑性变形。通过这种方式，可以实现表面硬化以及显微组织的变化。应用工艺策略对技术相关的生产过程车削进行互补加工会导致更复杂的接触条件。因此，刀具几何形状和对坚固的过程控制的需求带来了新的挑战。由于刀具刃口的适当的微观和宏观设计以及适应性较强的刀架，接触条件需要优化，因为组件条件可以被具体调整，并且刀具磨损可以减少到经济上可接受的水平。为此，计划对不同晶粒度的刀具材料(WC-Co)进行研究。为了提高刀具寿命和精确控制表层零件状态，需要分析深冷互补加工对刀具寿命的影响。使用低温冷却，应变硬化的潜力被认为是显着提高的。基于这些发现，将制定AISI 4140(42CrMo4)调质钢制造轴的工艺指南。计划中的研究将有助于更好地理解刀具刃口的微观和宏观设计之间的相互作用，以及通过互补加工实现的组织和部件条件。基于这些发现，考虑具有理想低温冷却系统的工艺，互补加工的工业相关性将被证明。

The aim of the research project is the application of the process strategy Complementary Machining on the technically relevant production process turning. Rotationally symmetric components like shafts made of the quenched and tempered steel AISI 4140 (42CrMo4) often represent highly stressed components whose surfaces are treated in a further process step after machining in order to ensure the desired properties. Component characteristics like the topography to optimize the tribological behavior or the service life of the parts are technically relevant target values. The component characteristics are usually achieved by expensive post production processes like deep rolling or hammer peening. With Complementary Machining the surface treatment is proceeded after machining without changing tools, by reversing the cutting direction and treating the surface of the component with the machining tool. Due to an extremely negative rake angle plastic deformation in the surface layer of the component is induced. In this way surface hardening as well as changes in microstructure can be achieved.Applying the process strategy Complementary Machining on the technically relevant production process turning leads to significantly more complex contact conditions. Thereof new challenges in terms of tool geometry and the demand for a robust process control result.Due to a suitable micro- and macroscopic design of cutting edges and an adaptable tool holder contact conditions are to be optimized since component conditions can be specifically adjusted and tool wear can be reduced to an economically acceptable level. For this purpose investigations of the tool material (WC-Co) with different grain sizes are planned. In order to increase tool life and precisely control component conditions in the surface layer the influence of cryogenically cooled Complementary Machining is to be analyzed. Using cryogenic cooling the potential of strain hardening is supposed to be significantly improved. Based on these findings a process guideline for producing shafts made of the quenched and tempered steel AISI 4140 (42CrMo4) will be derived.The planned investigations are intended to make significant contributions to a better understanding of interactions between the micro- and macroscopic design of cutting edges, their microstructure and component conditions that are achieved with Complementary Machining. Based on these findings considering a process with an ideal cryogenic cooling system the industrial relevance of Complementary Machining is to be demonstrated.