Blank Hydroforming Using Granular Material as Medium-investigations on Leakage
Blank Hydroforming Using Granular Material as Medium-investigations on Leakage
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DOI：
10.1016/j.proeng.2014.10.137
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
M. Grüner;Tobias Gnibl;M. Merklein
中科院分区：
文献类型：
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作者：
M. Grüner;Tobias Gnibl;M. Merklein
For high and ultra-high strength steel grades a forming at elevated temperatures is advantageous due to higher forming limits and reduced flow stresses resulting in low process forces. For highly complex parts out of these materials hydroforming is an appropriate production method allowing undercuts and homogeneous stretching of the material. In case of forming temperatures above 350 °C typical liquid forming media no longer can be used and gases are in the focus of interest. The big disadvantage of blank hydroforming at elevated temperatures results from the increase of friction coefficient by temperature and the need of sealing the cavity by high contact pressures in the flange area of the part. To overcome this challenge a third class of media, granular material like sand or small ceramic spheres can be used as forming media. For investigations of the process limits, especially the sealing limit of granular material, an experimental tool was built up.
