A. Toenjes, S. Ishkina, A. von Hehl, C. Schenck, H.-W. Zoch, B. Kuhfuss
December 11, 2018
Material properties like yield stress and hardness change during forming. Metastable austenitic steels are characterized by an elevated work hardening potential due to strain-induced transformation of austenite into martensite especially by multi-stage processing. An application of a new rotary swaging process design with Eccentric Flat Shaped Dies (EFSD) enables a severe shear strain in the workpiece. Eccentric rotary swaging typically provides a helical material flow. According to the process parameters, the microstructure features a typical eddy pattern with a spiral shaped grain orientation. The forming process can be carried out in one or more processing steps. The properties of the formed workpieces can be adjusted both by a variation of the process parameters values and by a specific subsequent heat treatment. This work is focused on microscopic investigations of the microstructure of in one and two steps eccentrically swaged parts with and without subsequent heat treatment.