P 1057 - Lightweight construction through targeted adjustment of local component properties with optimised forming and machining processes

P 1056 - Intelligent lightweight construction through multi-component processes The weight of drivetrain components has been continuously reduced through stress-optimised design and the resulting material savings in areas subject to low loads. With a consistent increase in power density and the associated reduction in weight, there is further potential for the intelligent lightweight construction of drivetrain components in the future. A holistic view of the design of the component, the material, the heat treatment and the manufacturing and joining processes used offers particular potential. By combining different manufacturing processes and materials, the various requirements of different component areas can be specifically fulfilled. This makes it possible to achieve a load-appropriate and cost-effective lightweight construction. Based on the multi-component construction method, solutions are developed to integrate solid individual components into overall structures. For example, higher-strength components made of steels with increased load-bearing capacity and optimised heat treatment operations open up additional fields of application for components produced using forming technology. High power density and lower component weight are achieved in gears built in this way by using a high-strength steel for a gear rim with the highly stressed toothing, which is combined with a wheel body in lightweight construction. lightweight construction. The wheel centre can be manufactured from high-strength sheet metal materials with a very low weight. Very light wheel centres with thin wall thicknesses are achieved by deep drawing. In addition, a weight saving is achieved during the packaging of sheet metal blanks by designing the spoke shape to withstand the stresses. The production of wheel bodies using forming technology also allows the positive and/or frictional joining of the spider, wheel body and shaft, thus enabling a compact, weight-optimised design. The thermal joining of an interference fit between the case-hardened ring gear and wheel centre can be carried out efficiently through the targeted use of temperature differences directly during quenching. Selected prototypes are examined with regard to functional behaviour and durability. The advantage of a design built in this way (differential design) over an integral design lies in the combinability of optimised processes for the production of individual components designed to withstand stresses. The individual component-related processes allow the respective processes to be optimised without having an unwanted influence on the other components, for example through integral heat treatment. FOSTA - Research Association for Steel Application e. V. February 2020 Participating companies: BMW Group, BorTec GmbH, CARL BECHEM GmbH, Daimler AG, Deutsche Edelstahlwerke, Faurecia Autositze GmbH, Georgsmarienhütte GmbH, GKN Driveline Trier GmbH, Hanomag Lohnhärterei GmbH, Härterei Tandler GmbH & Co. KG, Heess GmbH & Co. KG, HOERBIGER Antriebstechnik GmbH, Lindauer DORNIER GmbH, Mac Panther GmbH, Max Aicher Stiftung, MTU Friedrichshafen GmbH, Opel Automobile GmbH, Räuchle GmbH + Co. KG, RENK Aktiengesellschaft, Robert Bosch GmbH, Rohde Schutzgasöfen GmbH, Rohrwerk Maxhütte GmbH, Schaeffler Technologies AG & Co. KG, SEISSENSCHMIDT GmbH, Sidenor SA, SKF GmbH, Stelter Zahnradfabrik GmbH, SynOpt GmbH, thyssenkrupp Hohenlimburg GmbH, thyssenkrupp Steel Europe AG, TIME Technologie-Institut für, Vallourec Deutschland GmbH, Vestas Nacelles Deutschland GmbH, Volkswagen AG, ZF Friedrichshafen AG Research institutions: Institute for Forming Technology, University of Stuttgart Chair of Forming Technology and Foundry Engineering, TU Munich FZG - Research Centre for Gears and Transmission Engineering, TU Munich Leibniz Institute for Materials-Oriented Technologies - IWT, Bremen

P 1058 - Extending the technological limits of forging in different temperature ranges As an element of the lightweight solid construction research network, three demonstrator components were investigated in sub-project 4 "Extension of technological limits in solid forming in different temperature ranges", which were produced in different temperature ranges using fundamentally different solid forming processes. This sub-project is further divided into four work packages, which deal with different processes and demonstrator components. The content of the first work package consisted of investigating the manufacturability of a piston pin by stretch forming and the stiffness-related optimisation of a spiral-shaped inner contour with regard to its lightweight construction potential compared to a conventional cylindrical inner contour. In the second work package of the sub-project, the focus was on the production of a scaled gear shaft, also using a cold forging process, full forward extrusion. The aim here was to optimise the surface properties of hardness, roughness and residual stresses with regard to possible downsizing or the elimination of downstream heat treatment steps. With the aim of possibly substituting conventional hardening processes, extruded components were also deep rolled. The required parameter sets were determined on the basis of investigations on the starting materials. It was shown that already hardened components can be further strengthened by deep rolling. However, deep rolling of cold-formed components led to surface failure in the form of cracks in both the piston pin and the gear shafts. surface failure in the form of cracks and spalling. In the field of hot forging, multi-stage precision forging was successfully used to adjust local microstructural properties. A fine-grained microstructure with a typically good strength-to-toughness ratio was achieved on a gear rim through targeted thermomechanical treatment during individual part production. The results of the sub-project show impressively on the basis of the investigated demonstrator components that the processes of massive forming have numerous hidden potentials with regard to lightweight construction, which is increasingly taking centre stage. These processes in all temperature ranges allow the production of ever new component shapes with increasingly more efficient production sequences. In addition, it is generally possible to adjust local component properties in a targeted manner. To achieve this, the means of numerical process simulation must be utilised and further developed, and conventional forming processes must also be rethought. Although these points always entail new challenges, these can be overcome, as the results of the sub-project show, within the framework of joint research projects such as the research alliance for solid lightweight construction. FOSTA - Research Association for Steel Application e. V. February 2020 Participating companies: A. + E. Keller GmbH & Co. KG, BAUBLIES AG, CARL BECHEM GmbH, Cotarko GmbH, Daimler AG, ECOROLL AG, EZM Edelstahlzieherei Mark GmbH, Felss Systems GmbH, fischerwerke GmbH & Co. KG, Georgsmarienhütte GmbH, GKN Driveline Trier GmbH, HAMMERWERK FRIDINGEN GmbH, HOERBIGER Antriebstechnik GmbH, Houghton Deutschland GmbH, Johann Hay GmbH & Co .KG, LEIBER Group GmbH & Co. KG, Mahle GmbH, Mannesmann Precision Tubes GmbH, Max Aicher Stiftung, Muhr und Bender KG, Opel Automobile GmbH, Räuchle GmbH + Co. KG, Rohrwerk Maxhütte GmbH, Schaeffler Technologies AG & Co. KG, SEISSENSCHMIDT Components Processing GmbH + Co. KG, Sidenor SA, Simufact Engineering GmbH, SMS Group GmbH, Stelter Zahnradfabrik GmbH, Swiss Steel AG, SynOpt G Research institutes: Institute for Forming Technology and Forming Machines, Leibniz Universität Hannover Institute for Forming Technology and Lightweight Construction, Dortmund University of Technology Institute for Forming Technology, University of Stuttgart

P 1055 - Development of ultra-high-strength steels for alternative heat treatments and for cold forging of automotive powertrain components The increasing demands in the passenger car sector for safety, comfort and driving performance have led to a continuous increase in vehicle weight in recent years. In order to achieve further development in the area of driving dynamics in the future while at the same time reducing CO2 emissions and fuel consumption, this trend must be countered by new lightweight construction measures. Based on the current state of the art, approaches are being pursued in the field of material and structural lightweight construction as well as lightweight production and concept construction. As part of this research project, new steels and/or an adapted heat treatment for components used in the powertrain were developed. The focus was on lightweight material construction. According to a study by the Institute for Automotive Engineering at RWTH Aachen University (ika), approx. 1/3 of lightweight construction ideas for the powertrain are based on lightweight material construction. This study also identified the problem that, in many cases, measures in the field of lightweight material construction are usually directly linked to other measures in the field of lightweight design or lightweight manufacturing. The very high costs associated with this have so far led to major obstacles to the implementation of these lightweight material construction approaches. In this research project, this problem was addressed in co-operation with other sub-projects. An initial focus here was on the development and optimisation of steels with a higher load-bearing capacity for lightweight applications in the drivetrain. To this end, the chemical composition and heat treatment of case-hardening and heat-treatable steels already used on an industrial scale were modified in such a way that the potential of their property profile is utilised to a far greater extent than before. Furthermore, with a focus on large-scale realisation, new material concepts were specifically adapted to the promising heat treatment process of carbonitriding by means of microalloying, which lead to a higher component load-bearing capacity and thus have an increased lightweight construction potential. The lightweight construction potential was assessed using the gear component in extensive experimental load-bearing capacity tests. The second focus of the research project was to increase the lightweight construction potential of drivetrain components in conjunction with lightweight manufacturing. Of particular interest here is the cold forging of steels with a high forming capacity, which are more cost-effective than lighter aluminium alloys and have the required high basic strength. In order to ensure a reduction in production costs, subsequent heat treatment should be dispensed with. Newly developed but not yet commercially available materials with higher formability for cold forging were therefore optimised in terms of their property profile and manufacturing process. Publication: February 2020 Participating companies: ArcelorMittal Hochfeld GmbH, Bharat Forge CDP GmbH, Bodycote Wärmebehandlung GmbH, BorTec GmbH, Daimler AG, Deutsche Edelstahlwerke GmbH, EZM Edelstahlzieherei Mark GmbH, Felss Systems GmbH, fischerwerke GmbH & Co. KG, Georgsmarienhütte GmbH, GKN Driveline Trier GmbH, HAMMERWERK FRIDINGEN GmbH, Hanomag Lohnhärterei GmbH, Härterei Tandler GmbH & Co. KG, Heess GmbH & Co. & Co. KG, Hirschvogel Umformtechnik GmbH, Johann Hay GmbH & Co .KG, LechStahlwerke GmbH, Mannesmann Precision Tubes GmbH, Opel Automobile GmbH, Räuchle GmbH + Co. KG, RENK Aktiengesellschaft, Robert Bosch GmbH, Rohde Schutzgasöfen GmbH, Rohrwerk Maxhütte GmbH, Saarstahl AG, Salzgitter Mannesmann Forschung GmbH, Schaeffler Technologies AG & Co. KG, Sidenor SA, SKF GmbH, Swiss Steel AG, Vallourec Deutschland GmbH, Vestas Nacelles Deutschland GmbH, voestalpine BÖHLER Edelstahl, Volkswagen AG, ZF Friedrichshafen AG Research institutes: Institute of Ferrous Metallurgy, RWTH Aachen University Leibniz Institute for Materials-Oriented Technologies - IWT, Bremen FZG - Research Centre for Gears and Transmission Engineering, TU Munich

P 1059 - Innovation transfer, technical potential assessment and life cycle analysis This report summarises the results of sub-project 5 (SP5) in the "Lightweight construction" research network, which assumes a "bracketing function" in the overall project by including the processes downstream of the scientific and technological development of the components in the investigation programme with regard to economic implementation and sustainability. The project analysed the functioning of the sectoral innovation system and identified obstacles to innovation on this basis. In the area of steel and forming companies, for example, these exist in the form of established routines. System suppliers and OEMs do not yet have sufficient knowledge about the possibilities of new materials and component designs. In addition, the decision-making processes are sometimes quite complex due to the large number of relevant contacts. A particular obstacle is the lack of contact between steel and forming companies on the one hand and system suppliers and OEMs on the other. The industrial initiative and the research network have provided the impetus for reducing the barriers to innovation and for dealing more intensively with issues relating to solid lightweight construction. The stabilisation of the relationships between the stages of the value chain and the early involvement of forming companies in the development of new model generations represent important steps towards reducing the barriers to innovation. A positive distinguishing feature in the marketing of lightweight construction innovations can be the improvement in energy efficiency and driving safety. When evaluating the potential of primarily weight-reduced components, the focus is on efficiency (drivetrain) and driving dynamics (chassis). The result of the efficiency analysis is a reduction in energy consumption of approx. 0.1 litres of diesel fuel per 100 km and 100 kg in the NEDC. With regard to driving dynamics, an assessment of the improvement in driving safety and comfort as a result of the primary weight reduction was carried out on the basis of specific driving manoeuvres. Lightweight construction has a positive effect on braking distance and double lane changes (driving safety and dynamics). An analysis of secondary weight saving potentials shows that a primary weight reduction enables further potentials of approx. 30-50%. Finally, the life cycle analysis includes a holistic representation of the effect of lightweight construction measures for a gear wheel as a selected reference component. Publication date: February 2020 Participating companies: agentur im turm, Deutsche Edelstahlwerke GmbH, fischerwerke GmbH & Co. KG, Fuchs Schraubenwerk GmbH, Georgsmarienhütte GmbH, GKN Driveline Trier GmbH, Hirschvogel Umformtechnik Gmb, Max Aicher Stiftung, Opel Automobile GmbH, Räuchle GmbH + Co. KG, Robert Bosch GmbH, Rohrwerk Maxhütte GmbH, Saarstahl AG, Schaeffler Technologies AG & Co. KG, SEISSENSCHMIDT GmbH, Sidenor SA, SKF GmbH, Vestas Nacelles Deutschland GmbH, voestalpine Metal Engineering GmbH & Co. KG, Volkswagen AG, ZF Friedrichshafen AG Research institutes: RWI - Leibniz Institute for Economic Research (Essen) Institute for Automotive Engineering (ika) (RWTH Aachen)