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

淬火轴弯曲矫直的科学依据与建模淬火轴弯曲矫直是驱动技术零部件制造过程中的一个重要工序。从材料工程的角度看，它是一种弹塑性弯曲操作。结果，不均匀塑性变形导致复杂的多轴残余应力状态。在这种情况下，截面上的不均匀组织和强度，残留奥氏体的可能转变和潜在的强度差效应是重要的。在这方面的现有调查旨在缩短处理时间和避免损坏。关于弯曲矫直操作后的材料状态及其后果的基本信息缺乏。在项目的第一部分，将了解基本过程，例如局部塑性变形和残余奥氏体转变，以了解残余应力分布的形成。然后，研究这些材料状态对进一步加载下矫直方向以及相反方向的力学行为的影响。通过这种方式，将分析矫直操作对轴的机械行为的影响的重要方面。实验将辅以数值模拟，最终优化矫直策略。

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.