Microstructure and mechanical properties after case-hardening outside todays norms

A large part of the components used today, for example in gearbox construction, such as gears or bearing components, is adjusted to the stress during operation in a mostly thermochemical heat treatment process (usually gas carburizing). The resulting, mainly martensitic structure has been optimized in recent decades only within relatively narrow limits, especially with regard to increased component reliability and overall cost reduction. Due to increasing scarcity of resources and increasing limitations in terms of size or component weight, the trend in the recent past goes in the direction of increased load capacity or higher power densities. In addition to the use of costly high-alloy and / or high-purity material concepts, the research of novel surface-layer compositions has been brought into focus by mostly thermochemical heat treatment processes (i. e. carbonitriding). Before a possible adoption of these new boundary layer concepts into the industrial practice, however, a series of studies for better assessment and for a better understanding of the material-technical basics and relationships is necessary to assess potentials and risks. Important subgoals are: Detailed characterization and description of today's uncommon surface layer structure Testing and comparing novel heat-treated model samples with the standard to demonstrate the potential of the new heat treatment variants Basic studies on the conversion behavior and the retained austenite stability of the new process variant