Original Date: 11/03/1996
Revision Date: 01/18/2007
Best Practice : Superplastic Forming Technology
Since the early 1980s, Oak Ridge’s Y-12 Plant has been developing thermomechanical processing parameters and superplastic forming techniques for hundreds of parts. Superplastic forming came about because of the expense associated with processing and forming uranium alloys. By utilizing computers and process optimization techniques, superplastic forming diminished manufacturing space requirements, decreased material requirements by two-thirds, and significantly reduced processing and forming costs.
Through Y-12's research, superplastic forming can be applied to other alloys besides uranium such as titanium- aluminum-vanadium (Ti-6Al-4V), tin-lead (Sn-Pb), aluminum-magnesium (Al-Mg), and iron-chromium-nickel (Fe- Cr-Ni). Materials that exhibit superplastic behavior are preprocessed polycrystalline solids which can withstand large deformation before failure. Y-12 developed the superplastic forming technique as a sheet forming process where the sheet is placed over a female die and inert gas is applied at a few hundred pounds per square inch maximum.
Oak Ridge Centers for Manufacturing Technology (ORCMT) offers superplastic forming facilities for development activities as well as production operations. Capabilities include metallurgical support, dimensional analysis, and computer modeling. The computer modeling capability, based on a commercial package called NIKE, has been enhanced to address specific superplastic forming needs.
Because the superplastic forming process occurs just above the midpoint of the absolute melting temperature of the material, the technique produces a near-net shape, uniformly thick, and relatively stress-free product. The process also uses inexpensive die materials; forms large parts with low pressures; reduces tooling costs and fabrication time; and is inherently safer than the typical punch and die stamping operation.
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