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。特别是在制造技术中，存在尚未完全理解或充分利用的工艺优化潜力。例如，残余压应力可以通过加强循环应力部件的部件表面下区域来引入。它们对疲劳寿命的积极影响早已为人所知。残余应力深度可以通过创新的硬车轧工艺来影响，在该工艺中，由车削产生的热输入用于同时的深轧工艺。滚动轴承的硬车轧工艺的应用应导致更长的轴承疲劳寿命。台架试验表明，很高的最大残余压应力和大的渗透深度不能单独增加轴承的疲劳寿命。造成这种情况的原因可能是输入部件的热量无法具体控制，以及部件边缘区域由此产生的变化。在以前的研究中，没有全面考虑部件表面下及其对部件疲劳寿命的影响。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，并且有必要全面考虑组件的表面下。其目的是调查热机械处理影响作为一个整体的亚表面的程度，以及在何种程度上的亚表面的个别属性，如残余应力，纹理，微观结构和应变硬化状态，影响循环载荷下的疲劳和因果关系存在。在此基础上，定义优化的边缘区域特性，进行专门调整，并验证其对疲劳寿命的积极影响。在以前的调查中，没有全面考虑部件表面下区域及其对部件使用寿命的影响。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，并且有必要全面考虑组件次表面区域。其目的是调查热机械处理影响作为一个整体的次表面区域的程度，以及次表面区域的个别属性，如残余应力，纹理，微观结构和应变硬化状态，影响循环载荷下的疲劳和因果关系存在的程度。在此基础上，将定义优化的边缘区域特性，具体调整并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.