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Effects of Mechanical Properties on Biaxial Stretchability of Low Carbon Steels
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Abstract
The response of low carbon steel sheets to biaxial tension forces was studied in stretch cup tests of 3 and 8 in. diameter. Three levels of lubrication were obtained by the use of mineral oil, drawing compound, and hydraulic bulge pressure. The mineral oil and drawing compound were applied to hemispherical steel punches and a 0.004 in. thick polythene sheet was placed between these and the metal under test. Hydraulic bulge tests were relatively insensitive to plastic anisotropy changes in sheet metal. It was found that improving the lubrication in mechanical punch tests or lowering the plastic strain ratio r̄ had similar effects in increasing the height of the cup at fracture, transferring the maximum strains closer to the pole, and increasing the amount of strain which could be developed before fracture. Material with high strain hardening capacity distributed the strains more uniformly and therefore had better biaxial stretchability. Too little temper rolling applied to the sheets caused premature failure due to localized thinning and too much temper rolling caused a decrease in biaxial stretchability. It is concluded that interactions of material properties and test conditions are such that many factors must be considered in assessing sheet metal formability.
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Citation
Heyer, R. and Newby, J., "Effects of Mechanical Properties on Biaxial Stretchability of Low Carbon Steels," SAE Technical Paper 680094, 1968, https://doi.org/10.4271/680094.Also In
References
- Kaftanoglu B. Alexander J. M. “An Investigation of the Erichsen Test.” Journal of the Inst. of Metals 90 1961-1962 457 470
- Heyer R. H. Newby J. R. “Measurement of Ductility of Low Carbon Steel Sheets.” AIME Transactions - Flat Rolled Products I 1966
- Yokai M. Alexander J. M. “A Further Investigation of the Erichsen Test.” Sheet Metal Industries 44 July 1967 466 475
- Keeler S. P. Backofen W. A. “Plastic Instability and Fracture in Sheets Stretched Over Rigid Punches.” ASM Transactions 56 March 1963 25 48
- Lilet L. Wybo M. “The Effect of Plastic Anisotropy and Rate of Work Hardening in Deep Drawing.” Sheet Metal Industries 41 1964 783 815
- Lambert W. N. Madrzyk E. S. Gibson F. E. “A New Method for Determining the Drawing Quality of a Sheet by Use of the Hydraulic Bulge Tester.” Journal of Metals November 1960 857 860
- Heyer R. H. Newby J. R. “Measurement of Strain Hardening and Plastic Strain Ratio Using the Circle-Arc Specimen.” Sheet Metal Industries 43 December 1966 910 914
- Heyer R. H. Newby J. R. “Factors in Selecting Materials for Forming.” Metal Progress 91 March 1967 85 88
- Keeler S. P. “Determination of Forming Limits in Automotive Stampings.” SAE Transactions 74 1966 paper 650535
- Lloyd D. H. “Metallurgical Engineering in the Pressed Metal Industry.” Sheet Metal Industries 39 February 1962 82 94
- Rao U. S. “Polythene as a Lubricant for Deep-Drawing.” Sheet Metal Industries 44 October 1967 673 678
- IDDRG “The Plastic Anisotropy Ratio ‘r’ and the Work Hardening Exponent ‘n’ in Relation to the Drawability of Sheet Metal.” Sheet Metal Industries August 1967 523 532
- Keeler S. P. “Circular Grid System - A Valuable Aid to Sheet Metal Formability.” SAE Automotive Engineering Congress Detroit January 1968 paper 680092