Current research focuses on the targeted induction of predefined residual stress states during the manufacturing process. For instance, hot bulk forming offers a promising opportunity to modify residual stresses by utilizing thermal, mechanical and metallurgical interactions. In addition to precise residual stress control, time-consuming and cost-intensive subsequent treatments such as annealing or shot peening can be avoided. Here, hot bulk forming of a cylindrical specimen made from the Cr-alloyed steel 100Cr6 is considered. At first, the specimen is heated to over 1000°C resulting in complete austenitization and an initial stress-free condition. Then it is formed and lastly cooled down to room temperature. Different cooling routes lead to different phase transformation and residual stress states, e.g. rapid cooling by quenching in water leads to a diffusionless phase transformation from austenite to martensite, [1]. Since residual stresses are classified based on their scale, a distinction is made here between microscopic and macroscopic ones. Accordingly, two-scale FE2 methods can be used to analyze both types of stresses. Therefore, the phase transformation and other microscopic characteristics need to be accurately presented on the minor level. This work compares different methods to depict those phenomena in the representative volume element with respect to the residual stress evolution, [2]. It is shown that those different methods lead to different (microscopic) stress distributions. Thus, microstructural investigations are inevitable to predict residual stress states and evaluate the outcoming service life of a component. Further, experimental measurements and imaging techniques are necessary to describe phase transformation and material behavior accurately. [1] S. Uebing, D. Brands, L. Scheunemann and J. Schröder. Residual stresses in hot bulk formed parts: microscopic stress analysis for austenite-to-martensite phase transformation. Archive of Applied Mechanics, Vol. 91, 3603-3625, 2021 [2] S. Hellebrand, L. Scheunemann, D. Brands and J. Schröder. Numerical investigation of microscopic residual stresses evoked by phase transformation in hot bulk forming parts. International Journal for Multiscale Computational Engineering, Vol. 23, 2025.