Functionalized subsurface zone for load-oriented fatigue behavior of hardened components

由于全球经济和生态的发展，应用创新技术来保护环境和节约资源是必要的。特别是在制造技术方面，存在尚未完全了解或充分开发的工艺优化的潜力。例如，可以通过加强循环应力构件的构件表面下区域来引入残余压应力。它们对疲劳寿命的积极影响早已为人所知。残余应力深度可以受到一种创新的硬车削-轧制工艺的影响，在该工艺中，车削产生的热输入用于同时的深轧工艺。在滚动轴承上应用硬车滚压工艺应能延长轴承的疲劳寿命。台架试验表明，仅有很高的最大残余压应力和较大的残余压应力穿透深度不能提高轴承的疲劳寿命。出现这种情况的原因可能是无法具体控制的进入部件的热输入以及由此导致的部件边缘区域的变化。在以往的研究中，没有对构件亚表面及其对构件疲劳寿命的影响进行整体考虑。对于这里申请的项目，工作假设是热输入在深轧中起决定性作用，需要对部件亚表面进行整体考虑。目的是研究热机械加工对亚表面整体的影响程度，以及亚表面的个别性质，如残余应力、织构、显微组织及其应变硬化状态，对循环载荷下疲劳的影响程度，以及存在的因果关系。在此基础上，定义优化的边缘区域特性，并对其进行具体调整，验证其对疲劳寿命的积极影响。在以往的研究中，没有对部件表面下区域及其对部件使用寿命的影响进行全面考虑。对于这里申请的项目，工作假设是热输入在深轧中起决定性作用，需要对部件亚表层进行整体考虑。目的是研究热机械加工对亚表层整体的影响程度，以及亚表层的个别性质，如残余应力、织构、显微组织及其应变硬化状态，在多大程度上影响循环载荷下的疲劳，以及存在因果关系。在此基础上，定义优化的边缘区域特性，并对其进行具体调整，验证其对疲劳寿命的积极影响。

Due to the worldwide economic and ecological development, the application of innovative technologies to protect the environment and conserve resources is necessary. Particularly in manufacturing technology, there is potential for process optimization that is not yet fully understood or fully exploited. For example, residual compressive stresses can be introduced by strengthening the component subsurface zone of cyclically stressed components. Their positive effects on fatigue life have been known for a long time. The residual stress depth can be influenced by an innovative hard turn-rolling process, in which the heat input generated by turning is used for a simultaneous deep rolling process. An application of the hard turn-rolling process to rolling bearings should result in longer bearing fatigue lives. Bench tests showed that a very high maximum and a large penetration depth of the residual compressive stresses alone could not incease bearing fatigue life. The reason for this could be the heat input into the component, which cannot be specifically controlled, and the resulting change in the component edge zone. In previous investigations, no holistic consideration of the component subsurface and its effects on component fatigue life was carried out. For the project applied for here, the working hypothesis is that heat input plays a decisive role in deep-rolling and that a holistic consideration of the component subsurface is necessary. The aim is to investigate the extent to which thermomechanical processing influences the subsurface as a whole and the extent to which individual properties of the subsurface, such as residual stresses, texture, microstructure and its strain hardening state, influence fatigue under cyclic loading and which cause-effect relationships exist. Based on this, optimized edge zone properties are to be defined, specifically adjusted and their positive influence on fatigue life has to be verified. In previous investigations, no holistic consideration of the component subsurface zone and its effects on component service life was carried out. For the project applied for here, the working hypothesis is that heat input plays a decisive role in deep rolling and that a holistic consideration of the component subsurface zone is necessary. The aim is to investigate the extent to which thermomechanical processing influences the subsurface zone as a whole and the extent to which individual properties of the subsurface zone, such as residual stresses, texture, microstructure and its strain hardening state, influence fatigue under cyclic loading and which cause-effect relationships exist. Based on this, optimized edge zone properties are to be defined, specifically adjusted and their positive influence on fatigue life verified.