*2.2. Machining*

Machining is one of the most important steps in the process chain of manufacturing hybrid components because it determines the final surface and subsurface properties of a component. Therefore, it is essential to understand the influences of the machining parameters on the surface and subsurface properties of hybrid components. In this work, the influence of turning and deep-rolling parameters on these properties were investigated. At first, analogy studies were carried out on simplified component geometries, with friction-welded hybrid shafts of SAE5140 and SAE1020. With the help of analogy studies, correlations and interactions between process parameters and subsurface properties were investigated. Subsequently, with the knowledge of the machining behavior and its influence on the surface and subsurface properties, hybrid shafts with different manufacturing strategies were produced. The operating behavior of these hybrid shafts was then investigated by roller-bearing tests. The results were compared to conventionally manufactured shafts as a reference.
