Incremental Sheet-Bulk-Metal Forming by Application of Thermally-Controlled Grading Mechanisms

Funding: German Research Foundation (DFG)
Project: CRC/TR 73 • Subproject T04
Contact: Stephan Rosenthal M. Sc.

A challenge of incremental sheet bulk metal forming is to achieve a uniform edge thickness distribution from the sheet edge to the center of the sheet.

By means of thermally graded forming, the flow stress needs to be reduced locally in order to be able to influence the axial material flow in a targeted manner. With this strategy a homogenization of the thickened sheet height shall be achieved. The transfer project is being carried out in cooperation with the industrial partners Winkelmann Powertrain Components GmbH, Thyssenkrupp Hohenlimburg GmbH, Faurecia Seatings GmbH, and Voestalpine High Performance Metals Germany GmbH. Investigations intending to identify suitable process control strategies have shown that inductive heating is a promising approach for setting a sharp temperature gradient. In addition to the thermal grading, cryogenic cooling with temperatures down to -80°C is planned to be used. Thus, a further change of the yield stress in the outer boundary region of the sheet should be achieved.

a) Inductive heating with thermographic image, b) Possible cryogenic cooling setup