Influence of Initial Microstructure on Manufacturing Processes with Thermal Loads accompanied by Hardening

Abstract

Abstract The presented investigation focuses on the correlation between concrete physical loads and resulting modifications. The physical and in a wider sense chemical loads are called internal material loads. The correlation between the generated internal material loads and the modifications is called Process Signature. This contribution presents some Process Signature components for thermal dominated processes with phase transformation and accompanying hardening. The selection of the Process Signature components considers the residual stress state at the surface and the positions of the zero crossings of the residual stress curve. Based on Finite Element simulation and experimental work the external thermal loading of both processes were characterized by the resulting maximal temperature and temperature gradient, which correlates with the change of the residual stress state. During the CIRP CSI conference 2018 in Tianjin the authors presented results for the mentioned Process Signature components for a ferrite/perlite state. The actual work focuses on the question, how the above described Process Signature components depend on the initial microstructure of the steel. For this purpose the phase kinetics of different initial quenched and tempered states are investigated for fast heating processes up to 5000 K/s. Additionally the mechanical materials properties of these material states will be presented.