Project Details
Kinematic profile bending with locally heated cross-section for tailoring of mechanical properties
Applicant
Professor Dr.-Ing. A. Erman Tekkaya
Subject Area
Primary Shaping and Reshaping Technology, Additive Manufacturing
Metallurgical, Thermal and Thermomechanical Treatment of Materials
Metallurgical, Thermal and Thermomechanical Treatment of Materials
Term
since 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 408302329
Kinematic profile bending with locally heated cross-section enables the reduction of profile warping after bending of profiles with asymmetric cross-sections related to the force initiation axis. For this purpose, the flow stress is reduced in chosen cross-sectional areas of the profile through thermal softening. The flow stress reduction leads to a displacement of the shear center in direction of the force initiation axis, resulting in a reduction of the lever arm. Through the reduced lever arm, the torsion moment on the profile is lowered.The graded temperature field necessary for warping reduction can at the same time be used for tailoring of the mechanical properties of the profile material. For the tailoring of mechanical properties a quench hardening material and heating temperatures surpassing the materials recrystallization temperature are necessary. Through the increase in temperature parameters as heating rate, cooling rate and cooling temperature become relevant to set the resulting part geometry and part strength. Additional factors like phase transformations and increased volume changes occur due to the increased temperatures, leading to unwanted distortions of the profile.In the course of this project, the process of kinematic profile bending with locally heated cross-section will be extended to the possibility of tailoring the mechanical properties of the profile. Therefore, the influence of thermal and phase transformation effects on the forming and hardening results has to be characterized. Martensitic stainless steels will be used as profile material as these materials reach high hardness values with high heating and low cooling rates. To describe the process regarding resulting geometry and reachable strength of the bend profiles, metallographic investigations, tensile tests and bending tests of sheet and profile parts will be used. As a method to predict the resulting profile geometry and strength, numerical and analytical models will be developed. The process is relevant for industrial application as a combined flexible profile bending process without warping and the possibility to produce tailored parts.
DFG Programme
Research Grants
Co-Investigators
Professor Dr.-Ing. Till Clausmeyer; Dr.-Ing. Heinrich Traphöner