A New Method of Predicting the Formability of Materials
- Technical Paper
- ISSN 0148-7191
- DOI: https://doi.org/10.4271/720019
Published February 1, 1972 by SAE International in United States
The paper presents a new method, based on standard laboratory cup tests, for predicting the formability of materials; in the example provided, the forming potentials of four new materials are shown.
The properties of stretchability and drawability, which are the principal factors defining a material's forming limits, may be assessed using the Olsen spherical cup test and the Swift flat-bottomed cup test. In the shape analysis procedure described, the minimum amount of deformation needed to fix a desired shape is determined. Then necessary adjustments to tooling for optimum sheet metal usage are made based on calculations from a new type of chart showing stretch forming ratio and draw forming ratio, providing a comparison of the formabilities of a number of materials. It is shown that, in the absence of reliable cup testing data, values can be obtained using laboratory tensile testing results; this is possible because computer-determined correlations of certain tensile parameters to standard cup test results have been made.
CitationKasper, A. and VanderVeen, P., "A New Method of Predicting the Formability of Materials," SAE Technical Paper 720019, 1972, https://doi.org/10.4271/720019.
- Kasper A. S., “How We Will Predict Sheet Metal Formability.” Metals Progr., Volume 96, No. 5 (October 1969), pp. 159-164.
- Eary D. F. and Reed E. A., “Techniques of Pressworking Sheet Metal.” Englewood Cliffs, N.J.: Prentice-Hall, 1958.
- Koistinen D. P., “Heat Treatment to Eliminate the Upper Yield Point in Ferrous Alloys.” U. S. Patent 3,490,957, January 1970.
- Hook R. E., “The Effect of Quench-Aging on Inhomogeneous Yielding of Steels with Very Low Interstitial Solute Content.” Met. Trans., Vol. 1 (January 1970), pp. 85-92.
- Kasper A. S., “Forming Sheet Metal Parts.” Paper M. F. 69-516 presented at ASTME Creative Manufacturing Seminar, Chicago, January 1969.
- Yoshida K., “Shape Fixability of Steel Sheets in Press Forming.” (in English) Science Papers I.P.C.R. (Tokyo University), Vol. 59, No. 2 (June 1965), pp. 87-96.
- Private communication from H. Kitanishi, Nippon Steel Co. Ltd., Tokyo.
- Keeler S. P., “Circular Grid System-A Valuable Aid for Evaluating Sheet Metal Formability.” SAE Transactions, Vol. 77 (1968), paper 680092.
- Goodwin G. M., “Application of Strain Analysis to Sheet Metal Forming Problems in the Press Shop.” SAE Transactions, Vol. 77 (1968), paper 680093.