The superplasticity forming in aluminium alloy of Automotive Body Panels
In Europe and the U.S.A., many automobile manufacturers are turning to aluminium body panels to save weight and to improve fuel economy. For high volume production of panels with less than 35-40% equivalent strain, conventional multi-stage cold pressing may be used. However the tooling costs are very high. SPF is being recognized as a viable, cost effective alternative for prototype parts, pre-series parts, small to medium volume production parts and for parts with more than 40% equivalent strain.
This item is a cooperation between BRIMET and FIAT: The superplasticity forming in aluminium alloy of Automotive Body Panels . We are desirous to achieve sound engineering, design and economic benefits of SPF aluminium, competing with existing and emerging processes and alternative materials.
Up to now we have finished all the research work:
1. part choice(the front fender);
2. forming method choice(air bulging forming);
3. the initial metallurgical observation and simple tension test of the sheets(AA5182, AC121 and 660T4);
4. the free air bulging tests;
5. die design and the numerical simulation of superplastic air bulging of the fender;
6. moulds and heater system design.
The manufacture of moulds and heater system will has been completed in the middle of Apr. 2003. And then we will do a experiment for the aluminium (AA5182) front fender with SPF.
7. The result of the experiment
Following figures show some details of our work.
Fig.1 the front fender
Fig.2 Initial microstructure diagrm of the offered alloy
Fig.3 sample of bulged dome of 5182 alloy (370℃)
Fig.4 Die for the numerical simulation
Fig.5 Thickness distribution
Fig.6 the schematic diagrams of mould and heater system
Fig.7 The result of the experiment