Sonja Uebing

Abstract: Residual stresses in components are a central issue in almost every manufacturing process, as they influence the performance of the final part. Regarding hot forming processes, there is a great potential for defining a targeted residual stress state, as many adjustment parameters, such as deformation state or temperature profile, are available that influence residual stresses. To ensure appropriate numerical modeling of residual stresses in hot forming processes, comprehensive material characterization and suitable multiscale Finite Element (FE) simulations are required. In this paper, experimental and numerical investigations of thermo-mechanically processed steel alloy 1.3505 (DIN 100Cr6) are presented that serve as a basis for further optimization of numerically modeled residual stresses. For this purpose, cylindrical upsetting tests at high temperature with subsequently cooling of the parts in the media air or water are carried out. Additionally, the process is simulated on the macroscale and compared to the results based on the experimental investigations. Therefore, the experimentally processed specimens are examined regarding the resulting microstructure, distortions, and residual stresses. For the investigation on a smaller scale, a numerical model is set up based on the state-data of the macroscopic simulation and experiments, simulating the transformation of the microstructure using phase-field theory and FE analysis on micro- and meso-scopic level.

TL;DR: In this article, a numerical approach is presented to analyze the distribution of residual stresses resulting from cooling of a cylinder with an eccentric hole made of chromium-alloyed steel.

TL;DR: In this paper, a long-term study of residual stresses on hot-formed components is conducted, in order to develop finite element models for hot forming, a comprehensive thermomechanical material characterisation with special focus on phase transformation effects is performed.

TL;DR: In this article, a two-scale analysis of residual stress states in a hot bulk formed part with subsequent cooling in the framework of the $$\hbox {FE}^2$$¯¯ -method is presented.

TL;DR: In this paper, a multiscale view enables a detailed description of phenoma on the microscale such as the lattice shearing from face-centered cubic austenite unit cells to body-centered tetragonal martensite cells and is directly related to the typical classification of residual stresses following.