Different Friction Coefficients at Different Positions of Superplastically Formed Parts
Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review
Author(s)
Detail(s)
Original language | English |
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Pages (from-to) | 741-746 |
Journal / Publication | Materials Science Forum |
Volume | 304-306 |
Online published | 23 Feb 1999 |
Publication status | Published - 1999 |
Externally published | Yes |
Conference
Title | 2nd International Conference on Towards Innovation in Superplasticity |
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Location | |
Place | Japan |
City | Kobe |
Period | 21 - 24 September 1998 |
Link(s)
Abstract
The current study is to discuss that the degree of lubrication might be significantly different at different positions of a SPFed product. Numerous comparisons between experimental and predicted thickness profiles for open-die free bulging or close-die forming were made, using simulations based on systematic combinations of m, n and μ values. Current results suggest that the experimental thickness profiles fit best with the simulated distribution when using m=0.5 together with µ=∞ for the die entry portion and µ=0.01 for the bottom region. It we use the same friction coefficient for all positions, the predicted thickness profiles can never be close to the experimental ones. It was latter found that the lubricant powders would slide down along with the deformed sheet, from the upper die entry position down to the bottom center. The lubrication effect after the onset of SPF becomes different at different positions. There is almost no lubrication at the die entry (hence µ~∞) and near complete lubrication and free sliding at the central bottom region (hence µ~0). The discrepancy in experimental and predicted thickness profiles might not simply due to the wrong estimation of m-values, but could also be owing to different lubrication effects at different positions.
Research Area(s)
- Friction Effect, Lubricant Powders, Superplastic Forming
Citation Format(s)
Different Friction Coefficients at Different Positions of Superplastically Formed Parts. / Chen, T.-R.; Huang, J.C.; Hwang, Y.M. et al.
In: Materials Science Forum, Vol. 304-306, 1999, p. 741-746.
In: Materials Science Forum, Vol. 304-306, 1999, p. 741-746.
Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review