P 567 - Simulation-based optimisation of the forming - laser beam welding process chain

P 566 - Use of near-net-shape semi-finished steel products with variable diameters for hydroforming in the spinning - bending - hydroforming process chain The aim of the research project was to further develop hydroforming (hydroforming) for the production of complex lightweight steel components with highly varying cross-sections along the component's longitudinal axis. Until now, these components have usually only been achievable at great expense by utilising many process steps, such as intermediate heat treatments. The combination of the process steps spinning - bending - hydroforming investigated in this research project can achieve a significant reduction in costs, which represents a significant improvement with regard to the economical production of such components. As part of the investigation of the spinning process step, the so-called tube drawing was investigated for pre-contouring, whereby clamping devices and support devices in the form of special steady rests were developed. In this way, tubes could be tubes could be adapted to the cross-sectional profiles of a hydroforming mould with a high degree of accuracy. As a productivity-enhancing measure, a rotating spinning tool with several simultaneously engaged work rolls was developed and tested. In the area of bending technology, further developments had to be made due to the inconsistent bending properties of drawn-in pipes. On the one hand, a new rapid tooling concept for mould-based bending processes was developed, which is capable of producing the required contours with high accuracy and reproducibility. On the other hand, a second option for bending pre-contoured hydroformed semi-finished products was investigated based on three-roller bending using special elastomer rollers. The positive results, which were characterised by high contour quality and good process stability during the subsequent, very successful testing in the hydroforming process step, demonstrate the efficiency of the process chain pressing - bending - hydroforming and thus open up the possibility of manufacturing hydroformed components with cross-sectional jumps that cannot be produced with conventional semi-finished pipe products. The area of application for this new process chain is complex hydroformed structural components, for example in a steel spaceframe. In addition to such applications in automotive engineering, there are other potential areas of use, for example in rail and aircraft construction, apparatus engineering, sanitary engineering and the household appliance industry. Authors: M. Kleiner, S. Chatti, R. Ewers, M. Hermes, W. Homberg, R. Shankar Publication: 2006

P 568 - Possible applications of dry cutting and minimum quantity cooling lubrication in the machining of high-alloy, corrosion-resistant steel materials In the machining of steel materials, the use of conventional cooling lubricants is increasingly being replaced by the technologies of dry machining and minimum quantity cooling lubrication. While standardised solutions exist for numerous, easily machinable materials, the machining of high-alloy, corrosion-resistant steels places the highest demands on the design of the production processes. As part of the research project, experimental investigations were carried out into the turning and drilling of high-alloy, corrosion-resistant steels with different cooling lubricant concepts. The aim of the project was to highlight the possible applications of dry machining and minimum quantity cooling lubrication and to develop new solutions. The knowledge gained from the investigations allows easy transferability to other materials and related manufacturing processes. The results show that dry machining of corrosion-resistant steels is technologically feasible and economically viable in many cases. The performance of wet machining can be clearly surpassed if the processes are analysed in detail and the cutting parameters and tools are adapted. The reduction of cooling lubricant only poses major problems when machining heat-resistant materials with high toughness. Examples of this are high-alloyed austenitic-ferritic or nitrogen-alloyed austenitic steels. In order to ensure that the results obtained can be transferred to industrial practice, the production of a hexagon fitting screw was verified. It became clear that the process design, especially under the boundary conditions of dry machining, is of great importance. If the necessary process adjustments are made, economical machining is possible without any problems while maintaining the required quality characteristics. RESEARCH ASSOCIATION FOR STAHLANWENDUNG e.V. Publication: 2003 Authors: Prof. Dr.-lng. Dr. h.c. K. Weinert, Dipl.-Ing. S.Hesterberg, M.Sc., Dipl.-Ing. S. Wittkop

P 565 - Production of innovative hydroformed steel components based on novel, partially clad semi-finished sheet metal products As part of this research project, the technology of partial cladding for steel materials has been developed and the process chain "Partial cladding - hydroforming (hydroforming)" has been comprehensively investigated. Partially clad blanks are new types of double-sheet or multi-sheet semi-finished products that are joined together over their entire surface in defined sheet areas using a roll cladding process so that they partially form a solid material composite. By applying pressure to the unjoined areas of the double-sheet composite, sheet metal moulded parts with complex geometries can be produced using innovative hydroforming processes. Compared to thermal joining processes, roll cladding of double-sheet composites offers a number of important economic and technological advantages. As a continuous joining process, roll cladding enables a high output. Furthermore, a wide variety of metal combinations can be realised by cladding, which can also be multi-layered. The possibility of joining metals with different physical, chemical, mechanical or optical properties to form double-sheet composites opens up the possibility of new types of multifunctional integral components. One area of application for partially clad double sheets is the production of moulded sheet metal parts in the structural area of motor vehicles. In addition to such applications in automotive engineering, there are other potential areas of use, for example in rail and aircraft construction, apparatus engineering, air conditioning and sanitary engineering or the household appliance industry. The experimental and FE-based investigations presented in this report focus on - the production of partially clad sheet steel semi-finished products, - the resulting semi-finished product properties - and the hydroforming of partially clad sheet steel semi-finished products using selected example geometries. The application potential of partially clad hydroformed steel components for the application area of automotive body construction has been demonstrated on the basis of the production of a roof beam geometry and by means of investigations into its application behaviour. A supplementary economic evaluation of the semi-finished product and the "partial cladding - hydroforming" process chain also demonstrates the economic potential of this new technology. Authors: M. Kleiner, W. Homberg, B. Rauscher, M. Trompeter, H. Karbasian, M. Gösling, M. Köhler, T. Langhammer, F. J. Lenze, S. Schwarz Publication: 2007

P 561 - Forming-based joining for stainless steel façade elements Due to its typical properties, such as good formability combined with high component strength, steel offers excellent potential for architectural expression. As part of this project, the Chair of Forming Technology at the University of Dortmund used a new type of stainless steel façade system as an example for a new test hall, focussing in particular on questions relating to assembly technology, corrosion resistance and design. A key focus was the development and optimisation of the element geometry for this façade cladding. The individual elements had to be installed in such a way as to minimise surface damage and ensure all the relevant structural properties. At the same time, cost-effectiveness was to be improved through a quick, simple and functional installation technique. This objective was to be achieved through an assembly system with a high degree of prefabrication in the workshop to minimise on-site assembly times and the on-site use of a forming joining technique such as clinching. Construction and assembly of the realised stainless steel façade ultimately had to be carried out in a more conventional manner, as hand-guided setting equipment was not available for use on site during the construction phase. This restriction was primarily due to the system dimensions, which precluded the use of a non-stationary, hand-guided setting unit. With the specified geometric dimensions of the parts to be joined - especially the panels - accessibility to all the required joining points would only be possible with increased design and technical equipment - and therefore only with increasing mould masses. This meant that the use of a forming joining process was only possible to a limited extent in terms of the objective. As an alternative, the assembly technique - adapted to the selected panel geometry - was modified in such a way that concealed assembly points were used to prevent penetration of the façade surface. This surface-friendly installation technique is based on internal clamping elements that fulfil all the necessary static boundary conditions. It fulfils the requirement for shorter installation times on the construction site. The clamping elements are fastened quickly and easily using riveting technology with lightweight hand-held tools. The concealed mounting points significantly characterise the sophisticated visual appearance of the façade, especially in the stainless steel version presented here. The investigations show extended possibilities for the use of large-area elements as façade cladding. The assembly technique presented here was developed as an example for the construction of an external façade cladding made of stainless steel and can be transferred to other sheet materials with corresponding formability. This development work thus characterises the outstanding properties of steel as a material. In addition to the mechanical and technical requirements, the use of stainless steel also fulfils further requirements in terms of appearance and design. RESEARCH ASSOCIATION FOR STAHLANWENDUNG e.V. Publication: 2004 Authors: Prof. Dr.-Ing. M. Kleiner, Dr.-Ing. F.-J.Kleiner