White Etching Areas in Bearing Steel 100Cr6

应用项目的总体目标是为了解白色蚀刻区域(WEA)的形成机制和导致WEC(白色蚀刻裂缝)的破坏机制的公开问题提供答案。基于显微组织变化导致裂纹形成这一研究假设，提出了应用项目的以下部分目标：1.在滚动接触疲劳试验机上可重复产生WEA/WEC。2.高分辨率微结构--WEA区域微结构转变的分析特征。3.用透射电子显微镜对WEA区进行了详细的研究。4.WEA形成时局部温度的理论确定。5.利用连续介质力学方法，对细观条件下的数值模拟进行了识别，并对观察到的WEA区域的微观结构变化进行了解释。通过耦合数值模拟，考虑了从贝氏体组织到过饱和铁素体的相变，以及由于其高强度而在WEA内形成的应力集中。这项研究的目的是证明WEA中的应力可能会上升到很高，导致该地区形成裂缝。在拟议的项目中，将不会对裂纹的形成和扩展进行显式模拟。

The overall goal of the applied project is to provide answers to open questions regarding the understanding of the formation mechanisms of WEA (White etching areas) and damage mechanisms leading to WEC (White etching cracks). Based on the research hypothesis 'Microstructural changes lead to crack formation' the following partial goals for the applied project emerge: 1. Reproducible creation of WEA/WEC on a rolling contact fatigue testing machine. 2. High resolution microstructure-analytical characterisation of the microstructural transformations in the region of the WEA. 3. Detailed investigations of the WEA regions with transmission electron microscopy. 4. Theoretical determination of the local temperature at the formation of the WEA. 5. With the help of a continuum mechanical, numerical simulation in mesoscopic scale conditions are to be identified, with which the observed microstructural changes in the region of the WEA can be explained. Using coupled numerical simulations, the phase transformation from the bainite structure to the supersaturated ferrite is to be considered as well as the stress concentration within the WEA formed due to their high strength. The study aims to prove that the stress in the WEA could rise very high, leading to crack formation in this area. An explicit simulation of the crack formation and -propagation will not be conducted in the proposed project.