Investigation of Skin-Pass Rolling With a Focus on Surface

An important characteristic of rolled aluminium strips for use in the automotive outer skin is the surface quality. The topography of the surface and in particular the number of roughness peaks as well as the volume of closed lubrication pockets influence the success of the subsequent process steps deep drawing and painting.
The work carried out so far has investigated the relationship between the process kinematics of skin-pass rolling and the transfer mechanisms. For this purpose, the kinematics of a process model of flat rolling was transferred to a mesomodel to describe the surface imprinting. With regard to the imprinting of the surface, a good correspondence between simulation and experiment could be shown.
In the medium term, the numerical model is intended to enable a knowledge-based design of the skin-pass process for aluminium alloys, taking into account global and local influences.

For further information, please contact Michael Riedel.

Finite-Element Based Estimation of the Lifespan of Wear-Resistant Coating for Cold Rolling

For cold rolling of steel, due to large plastic deformation, the periodic mechanical stress on work rolls is quite significant and often causes severe wear, which terminates the production and reduces the efficiency. To increase the lifespan of the work rolls, wear-resistant coatings are applied. However, the lifespan of work rolls with a specific coating category and thickness cannot be scientifically estimated, which causes difficulties in the coating selection and application for other forming technologies. In this project, multi-scale FE models are used to estimate the lifespan of coatings. In macro model the kinematics and stress in roll gap are simulated and afterwards transferred to a meso model as boundary conditions. In the meso model, the coating behaviour can be simulated using a bonding model under realistic forming condition as in the roll gap.

For further information, please contact Holger Brüggemann.