International Symposium on Green Manufacturing and Applications (ISGMA 2016)
Cold forming processes are very efficient for bulk production. However, the achievable geometries are restricted not only by the process kinematics and tools but also by work hardening. Especially with metastable austenitic steels higher deformation degrees cannot be achieved due to the deformation induced martensitic transformation of austenite which leads to an even higher hardening of the workpieces. To adjust the forming characteristics (formability, microstructure) a rotary swaging process is adapted in the way that higher shear deformation is applied. In the new approach a shift of the axial centerline of the workpiece from the original center of the closed dies is realized. It leads to non-symmetric material flow during each stroke and in combination with the rotation of the swaging head a helical deformation of the original center line of the workpiece is achieved. The center line in the sense of straightness is restored by robust guiding. Forming tests were performed with AISI304. The resulting material properties are illustrated by tensile tests, martensite content measurements and micrographs.