Tailored Preforms
Examples for tailored preforms are sheets with weight-optimized thickness distribution, near net shape forming, semi-finished products made of a combination of different metals as well as high-performance materials. They can be used for lightweight design, cost reduction and functional integration.
The research topics embedded in this cross-sectional area are assigned to different research groups and are presented below.
Flexible Rolling Flexible Rolling enables the production of metal strips with a variable thickness in longitudinal direction. Employing such semi-finished products enables the development of load-aligned structural components. Compared to conventional components light-weight design becomes possible and resources can be saved. During the process, the roll gap is adjusted according to pre-calculated trajectories resulting in the desired thickness distribution. Based on research on the layout of a suitable process control Flexible Rolling has made the step to an industrial-scale application at the company Mubea. A wide variety of thickness profiles and materials is produced for various applications such as automotive parts. For further information, please contact Dorothea Czempas. Image: Roll stand for Flexible Rolling, Copyright: IBF |
Strip Profile Rolling Strip Profile Rolling is a modified rolling process allowing for a thickness variation transversal to the rolling direction. Such semi-finished products offer a potential for light-weight design and enhanced use of material. In order to achieve a thickness distribution in transversal direction it is necessary to use narrow rolls. Narrow rolls guide the material flow into the transverse direction and thereby prevent buckling even though there is an inhomogeneous thickness reduction in transversal direction. A multi-pass process on a strip profile rolling machine can achieve a distinct width of the area with reduced thickness. Besides the investigation of process boundaries, a combination of Strip Profile Rolling and Flexible Rolling has been investigated. A combination of these processes can lead to semi-finished products in both longitudinal and transversal direction. For further information, please contact Pavlo Pavliuchenko. Image: Machine for Strip Profile Rolling and rolled strip, Copyright: IBF |
Strip Casting of Strips With Tailored Cross Sections Load optimized parts are indispensable in modern light-weight constructions. But their production is still extensive and non-trivial.
For further information, please contact Max Müller. Image: Schematic depiction of the strip casting process, Copyright: IBF |
High Precision Rolling with Roughness Control In a joined project with the Institute of Automatic Control of the RWTH Aachen University, new approaches to extend the flexibility and process window of the imprinted roughness of a skin-pass rolling process are investigated. Based on the previous research project of the high precision rolling with piezoelectric actuators, a fast rolling model and its online identification, the strip tension is used as an additional actuator to control the imprinted roughness during skin-pass rolling. A model-based control is realized from the results of FE simulations. To identify the deviation and defects during the process, an optical roughness sensor has been integrated in the high precision rolling mill des IBF integriert. Ziel ist es die Lackierbarkeit sowie die tribologischen Eigenschaften der Produkte durch einen Softsensor mit Eigenschaftsmodellen vorherzusagen. For further information, please contact Xinyang Li. Image: Slit strip runs into a 4-high stand, Copyright: Martin Braun |
Profile Ring Rolling Profiling of ring rolled components is an important step for the near net shape production, which leads to material savings as well as time saving regarding the machining. Based on the area of application, all four sides of the cross section can be profiled. Dependent on the type of the profile and the geometry of the ring different challenges during the process occur. Examples for these challenges are the reaching of the desired profile filling and conicity in the cross section. For further information, please contact Mirko Gröper. Image: Axial roll gap during the axial profiling process, Copyright: IBF |
Increasing the Range of Geometries in Open-Die Forging Open-die forging is an incremental bulk metal forming process, which is mainly used for the production of long and straight workpieces with a simple geometry as round or square. The production of complex geometries by open-die forging usually requires additional manufacturing steps or can only be realized by a high amount of machining. A new manufacturing approach is based on the idea to realize the production of complex workpieces through superimposed manipulator displacements during a forging stroke. Due to the plastic state of stress, already small superimposed stresses are sufficient to control the material flow towards the intended final geometry. This new forging method was successfully realized for the production of curved and twisted workpieces from steel and aluminium using the open-die forging center at IBF. The general approach significantly increases the range of producible geometries in open-die forging. For further information, please contact Fridtjof Rudolph. Image: Production of curved workpiece by superimposed manipulator displacements, Copyright: IBF |
Roll Bonding Technology Roll Bonding is a process to join at least two metals permanently using rolling and possibly higher temperature. For further information, please contact Aron Ringel. Image: Roll stock in roll gap, Copyright: IBF/Hydro |
Clad Strip Produced by Vertical Strip Casting Clad metals are found in various applications, since they allow for cost-efficient combination of properties of different metals and alloys. Their wide-spread application means several production methods already exists, albeit each with their own limitations. Their production via vertical strip casting poses an alternative, which exploits the short process route of twin-roll strip casting to address these limitations. The Institute of Metal Forming operates its own twin-roll caster. On this caster a prefabricated strip is inserted into the process and, exploiting the process heat, a bond between prefabricated and cast strip is created in the roll gap. Clad strips with thickness ratios between cast and inserted strip of 6:1 to 10:1 have been realized for various steel alloy pairings. The strips have been subsequently examined to describe and understand the underlying bonding mechanism. As the next step cladding of steel strips with non-ferrous metals via this route is to be researched. For further information, please contact Max Müller. Image: Clad pipe segment produced by twin-roll strip casting, Copyright: IBF |
Form Closure by Rolling Lightweight-design is an ongoing trend in the automotive industry. New materials and processes reveal new opportunities to reduce the weight of car bodies. One option to produce these optimized components is a combination of a steel sheet with a reinforcing aluminium rib structure. By the use of specific surface structures a clamping of the components should be achieved resulting in a high stiffness of the components. For further information, please contact Aron Ringel. Image: Form closure connection of aluminium and steel, Copyright: IBF |
Twin-Roll Strip Casting of High Manganese Steels Within the collaborative research project SFB 761 “Steel – ab initio“, the entire process chain for the production of high and medium manganese steels, including strip casting, hot and cold rolling is investigated. The investigated steel alloys require comprehensive adaptions regarding casting additives, refractory material, and casting, hot and cold rolling parameters. In addition, potential opportunities for influencing the mechanical properties of the strip by varying the casting and rolling parameters will be examined. Thus, taking advantage of the outstanding strain hardening behavior of these manganese steels enables the production of tailor-made semi-finished products in a drastically shortened process chain. For further information, please contact Max Müller. Image: Strip cast high manganese steel coil, Copyright: IBF |