In current research, the aim is to induce targeted residual stress states during the manufacturing of a component. Thereby, cumbersome subsequent treatments, which are often very time-consuming and cost-intensive, can be opposed. For instance, hot bulk forming processes have the potential to modify residual stresses by exploiting thermal, mechanical and metallurgical interactions and at the same time, enables precise stress control. Typically, a hot bulk forming process consists of three steps, namely heating, forming and cooling of the material. Here, during the last step, the cooling, a phase transformation occurs. This phase transformation is defined by different characteristics, e.g. rapid cooling by quenching in water leads to a diffusionless phase transformation from austenite to martensite in the considered material 100Cr6. By adapting the cooling strategy, the process can be optimized in such a way that costly post-treatments become dispensable. In this contribution a model is presented to depict the cooling process and the associated phase transformation, which generates residual stresses in the material. Generally, such residual stresses are classified according to their scale, here a distinction is made between microscopic and macroscopic ones. Macroscopic residual stresses can be modeled using Finite Element simulation techniques. Since microscopic residual stresses leading to microscopic cracks and possible failure mechanisms, microscopic analyses are very important. Thus, a multi-phasefield model is set up to model these microscopic stresses as well as the microscopic evolution in the hot bulk forming process. Therein, different aspects such as grain structure and plastic effects are discussed.