IBF© Foto: Martin Braun
The institute’s fields of work and research areas are structured according to the process chains of metal forming as well as to the methods of material testing, modeling and simulation.
Key Research Areas
A) Rolling and Drawing
The main topics of the institute for the production of flat products by rolling are the optimization of rolling parameters for the adjustment of material properties and the development of new rolling processes for application adjusted semi-finished products. For example fast numerical simulation models are used for designing pass schedules and for the prediction of microstructure development along the process chain. Both strips with a variable thickness over the width (Tailor Rolled Strips) for lightweight construction and rolling of riblet surfaces (“shark skin”) could lead to a substantial reduction of planes’ kerosene consumption. Researches of the tribology of rolling and the application of lubricants target economic and ecological improvements.
Concerning the long products, analyses of wire and profile drawing processes are possible as well as the development of production strategies for thin strips on a precision micro rolling mill.
B) Strip casting
Strip casting is an innovative process to produce hot rolled strip directly form molten steel. This allows a significant reduction of energy and capital investments compared to the conventional continuous casting process and subsequent hot rolling. Additionally, the rapid cooling leads to an excellent micro structure. In cooperation with industry a fully automated experimental facility is utilized to optimize process technology and to research the potentials of processing new materials.
C) Bulk components and ring rolling
Concerning forging, the focus lies in open die forging, which is used for the production of products with large geometries. The forging center with its 6.3 MN press and its modern robot manipulator allows the development of new forming strategies. In combination with numerical process simulation and material modeling the development of models for optimization of the process is possible. Additionally, strategies for complex geometries, e.g. hollow shafts for wind power plants, can be created. For closed die forging the focus lies on lubrication and the modeling of microstructure.
Regarding ring rolling the institute researches new process controls for the flexible forming of axial and radial profiled rings, using a ring rolling machine for production of seamless rings up to a diameter of 2 m. For the numerical simulation of this complex process the entire machine including the closed-loop control system has to be modeled in simulation.
D) Sheet metal forming
Aeronautic and automotive industries rely on sheet metal forming processes. The institute researches both, conventional deep drawing and in particular modern special forming technologies. For example, a spin-off company (KSA GmbH) in Aachen produces components for the ARIANE rocket by shot-peening. In Incremental Sheet Forming a CNC controlled tool forms complex geometries step-by-step. In the future, this process could close the technological gap for the effective production of sheet components in small quantities. On that account the institute uses a unique experimental facility which allows the combination with stretch-forming for parts up to the size of 1m x 1m. Sophisticated optical measurements technology (ATOS, TRITOP, ARGUS and ARAMIS) is utilized for characterization, digitalization and strain analysis of sheet metal products.
E) Process simulation and materials modeling
Prerequisite for simulation and modeling of metal forming processes and process chains is the knowledge of simulation methods, metal forming basics, material behavior and boundary conditions. Thus, high-level process simulation is conducted with different finite element software used in science and industry, always in adjustment with experimental results. The advancements in numerical methods include optimization strategies, scale independent simulations and considering machine behavior in simulation.
Regarding material modeling the institute relies on a modern material testing laboratory. For example, the determination of isothermal cold and hot flow curves with a constant strain rate is possible. Furthermore, the facilities provide the identification of kinetics of recrystallization, recovery and grain growth as well as boundary conditions (friction, heat transfer, radiation) and the physical simulation of forming processes in several steps. These experimental potentials are the basis for the development and FEA implementation of sophisticated microstructure models during and after hot forming, based on phenomenological and metal physical approaches.