Tube forming technologies based on internal forming pressures, such as hydroforming or hot tube gas forming, are state of the art to manufacture complex closed profile geometries. However, materials with excellent specific strengths and chemical properties, such as titanium alloys, are often challenging to shape due to their limited formability. In this study, the titanium alloy Ti-3Al-2.5V was processed by superplastic hot tube gas forming to manufacture a helically shaped flex tube. The forming process was investigated in terms of process simulation, forming tool technology and process window for the manufacturing of good parts. Within a simulation study, a strain rate optimized forming pressure–time curve was defined. With the newly developed tool design, forming temperatures up to 900 °C and internal forming pressures up to 7 MPa were tested. A process window to manufacture good parts without necking or wrinkling has been successfully identified. The experiment data showed good agreement with the numerical simulations. The detailed study of the process contributes to an in-depth understanding of the superplastic forming of Ti-3Al-2.5V during hot tube gas forming. Furthermore, the study shows the high potential of superplastic hot tube gas forming of titanium alloys for the manufacturing of helical flex tubes and bellows.

Influence of surface pressure and tool materials on contact heating of aluminum TRÂN Ricardo, PSYK Verena, WINTER Sven, KRÄUSEL Verena [button link="https:/

The amount of complex profile components in car bodies increases due to the emerging electromobility. High-strength aluminum alloys are ideally suited as material for automotive applications due to their extraordinary lightweight construction potential. The presented study focuses on the transfer of established thermo-mechanical manufacturing processes for sheet metal components to hydroforming of tube material. Demonstrator components are produced from EN AW-7020 using W-temper-forming and hot forming and compared numerically and experimentally. The results show that the determined material properties are sufficiently accurate to numerically represent the temperature-supported processes with excellent precision. The formed components can be used to demonstrate the potential of hydroforming for high-strength aluminum tubes using W-temper-forming and hot forming.

-Investigations on the production and forming of thermoplastic ceramic green tapes TRÂN Ricardo, MANNSCHATZ Anne, PSYK Verena, GÜNTHER Anne, DIX Martin [but

In order to increase the energy efficiency of transportation, the mobility market is increasingly focusing on weight reduction. It is anticipated that the proportion of aluminium alloys in the mobility sector will continue to increase. High-strength aluminium alloys and next generation alloys with increasing amounts of secondary aluminium require the development of energy and cost efficient heat treatment technologies for the thermomechanical treatment of sheet metal material. Contact heating as a rapid heating process can be a promising technological approach to efficiently preheat aluminium components for subsequent temperature assisted forming processes. This paper focuses on the analysis of the different influencing factors during the contact heating process and the investigation of the influence of the microstructure of the aluminium alloys on the heating process. Based on preliminary investigations [1], a full-scale contact heating tool has been developed which has been used to study aluminium sheets with thicknesses between 1.0 mm and 5.2 mm at various temperatures, highly thermally conductive contact plate materials (CuCr1Zr and CuZn39Pb3) and surface pressures between 3 MPa - 15 MPa. The investigation of the high-strength aluminium alloy EN AW-7075 revealed that the heating rates are predominantly influenced by the thermal conductivity of the contact plate materials rather than by the surface pressures. Furthermore, it was determined that sheets with coarse-grained microstructures exhibit faster heating rates. The study also successfully demonstrated the feasibility of the contact heating concept with highly thermally conductive contact plates for larger components (300 x 300 mm), which emphasises the future usability of the heating process for subsequent forming processes for larger components.