Bend-Straightening of Case-hardened Shafts - Scientific Basis and Modeling

淬火轴弯曲矫直的科学依据和建模淬火轴弯曲矫直是传动技术零件制造过程中的重要工艺步骤。从材料工程的观点来看，这是一种弹塑性弯曲操作。因此，发生不均匀的塑性变形，导致复杂的多轴残余应力状态。在这种情况下，不均匀的显微组织和强度的横截面中，残余奥氏体的可能的转变和潜在的发生强度差异效应是重要的。在这方面，现有的调查旨在缩短处理时间和避免损坏。缺乏关于弯曲矫直操作后材料状态及其后果的基本信息。在项目的第一部分，基本过程的理解，e。G.局部塑性变形和残余奥氏体转变的关系，以了解残余应力分布的形成。然后将研究这些材料状态对在矫直方向上以及与矫直方向相反的方向上进一步加载下的机械行为的影响。通过这种方式，将分析矫直操作对轴的机械行为的后果的重要方面。实验将通过数值模拟进行补充，并最终实现优化的矫直策略。

Bend-straightening of case hardened shafts scientific basis and modelingBend-straightening of case hardened shafts is an important process step during manufacturing processes of components for drive technology. From the viewpoint of materials engineering it is an elasto-plastic bending operation. As a consequence, inhomogeneous plastic deformations occur leading to complex multiaxial residual stress states. In this context, inhomogeneous microstructure and strength in the cross section, a possible transformation of retained austenite and a potentially occurring strength-differential-effect are of importance. Existing investigations in this context are targeted towards shortening of process times and avoiding damage. Basic information about the materials states after bend-straightening operations and their consequences are lacking. During the first part of the project, an understanding of the basic processes, e. g. of local plastic deformations and retained austenite transformations will be gained to understand the formation of residual stress distributions. Then the consequences of these materials states on the mechanical behavior under further loading in the straightening direction as well as opposite to it will be studied. In this way, important aspects of the consequences of straightening operations on the mechanical behavior of shafts will be analyzed. Experiments will be complemented by numerical simulations and will finally enable optimized straightening strategies.