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Hydro forming at elevated temperatures

: Neugebauer, Reimund; Schieck, F.

Hwang, Y.-M. ; National Sun Yat-Sen University -NSYSU-, Kaohsiung:
Tube Hydroforming Technology 2009 : TubeHydro 2009; Proceedings of the 4th International Conference on Tube Hydroforming, September, 6-9, 2009, Kaohsiung, Taiwan
Kaohsiung: National Sun Yat-sen University, 2009
ISBN: 978-957-9014-45-8
ISBN: 957-9014-45-0
International Conference on Tube Hydroforming (TUBEHYDRO) <4, 2009, Kaohsiung>
Conference Paper
Fraunhofer IWU ()
hydroforming; elevated temperature; aluminum; magnesium; titanium

Hydro-forming of tubes and blanks as a forming medium, using water at room temperature represents state-of-the-art for a number of applications in car body structures or exhaust systems, as well as for special applications outside the car industry. These parts are mainly made from steel, high strength steel, stainless steel and aluminum.
New requirements from industry in particular with lightweight design calls for the increased use of new construction materials, such as aluminum, magnesium titanium or steel alloys with maximum strengths of up to 1.000 MPA and higher. Parallel to the requirement for alternative materials, the shape of the parts is also becoming increasingly complex. Conventional hydro-forming techniques are coming closer and closer to their technological limits.
Improvements to hydro-forming technology incorporate new solutions for using temperature as an additional process factor. Most of the materials used for hydro-forming demonstrate much better formability at elevated temperatures. In order to make full use of these possibilities it was necessary to find new temperature-resistant forming media. The first step was thermal oil up to 300°C, the second step permits the utilisation of gaseous medias, such as nitrogen, forming temperatures up to 1 000 °C.
During this development process not only a large number of test parts and prototypes were produced, also first series applications were realized, mainly in aluminum. Increasing the thermal process limits has also made it possible today to produce parts not only in magnesium but also in titanium (600°C) and steel (900°C).
In addition, it has been established that it is feasible to combine the hydro-forming process at elevated temperatures with joining applications or a special head treatment (steel), similar to the hot stamping of blanks. Initial tests show the potential of such integrated processes to produce extremely light and strong structures to meet the requirements of the future.