Development of a Profile Bending Process with Compressive Stress Superposition by Rolling

Funding: LeitmarktAgentur.NRW
Project: EFRE-0400139
Contact: Juri Martschin M.Sc.

As part of this NRW patent validation, a process is developed that enables profile bending with compressive stress superposition.

The stress superposition is realized by the combination of flexible and fixed rollers (see figure). The unique feature of the process, compared to conventional profile bending processes with stress superposition, is the closed roll gap to build up an even pressure. Numerical simulations show a significant reduction of the bending force when working with a contemporaneous cross section reduction. The direct relation to the springback also reduces the shape deviation significantly (see figure). The cause can be attributed to the shift of the yield curve to more favorable bending stresses. The aspired use of a special roll stand in combination with a mandrel system will provide the possibility to change the profile cross section over the longitudinal axis. This allows to produce load-adapted profiles with versatile contours.

Springback S over the radius RL with and without cross section reduction based on FEM simulations