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Forming Limit Analysis of DP600-800 Steels

Authors: M. C. Cardoso, L. P. Moreira

Abstract:

In this work, the plastic behaviour of cold-rolled zinc coated dual-phase steel sheets DP600 and DP800 grades is firstly investigated with the help of uniaxial, hydraulic bulge and Forming Limit Curve (FLC) tests. The uniaxial tensile tests were performed in three angular orientations with respect to the rolling direction to evaluate the strain-hardening and plastic anisotropy. True stressstrain curves at large strains were determined from hydraulic bulge testing and fitted to a work-hardening equation. The limit strains are defined at both localized necking and fracture conditions according to Nakajima’s hemispherical punch procedure. Also, an elasto-plastic localization model is proposed in order to predict strain and stress based forming limit curves. The investigated dual-phase sheets showed a good formability in the biaxial stretching and drawing FLC regions. For both DP600 and DP800 sheets, the corresponding numerical predictions overestimated and underestimated the experimental limit strains in the biaxial stretching and drawing FLC regions, respectively. This can be attributed to the restricted failure necking condition adopted in the numerical model, which is not suitable to describe the tensile and shear fracture mechanisms in advanced high strength steels under equibiaxial and biaxial stretching conditions.

Keywords: Advanced high strength steels, forming limit curve, numerical modeling, sheet metal forming.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1108508

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References:


[1] Gan, Y., Advanced Steel and Our Society: Better Steel, Better World, “Advanced Steels: The Recent Scenario in Steel Science and Technology,” Eds, Weng, Y., Dong, H, Gan, Y., German. Metallurgical Industry Press, Beijing and Springer-Verlag GmbH Berlin Heidelberg, 2011.
[2] S.P. Keeler, W.A. Backofen, “Plastic instability and fracture in sheets stretched over rigid punches,” ASM Trans. Quart. 56, 25, 1964.
[3] G.M. Goodwin, “Application of strain analysis to sheet metal forming problems in press shop,” SAE Paper No. 680093, 1968.
[4] R. Hill, “On discontinuous plastic states, with special reference to localized necking in thin sheets,” J. Mech. Phys. Solids 1, 1952.
[5] Z. Marciniak, K. Kuckzynski, “Limit strains in the processes of stretchforming sheet metal,” Int. J. Mech. Sci. 9, 1967, pp. 609–620.
[6] M. Koç, E. Billur, O.N. Cora, “An experimental study on the comparative assessment of hydraulic bulge test analysis,” Materials and Design 32, 2011, pp. 272–281.
[7] R. Hill, “A theory of plastic bulging of a metal diaphragm by lateral pressure”, Philos. Mag. Series 7 40, 1950, pp.1133-1142.
[8] M. M. C. S. Freitas, L. P. Moreira, R. Garcez, “Experimental analysis and theoretical predictions of the limit strains of a hot-dip galvanized interstitial-free steel sheet,” Materials Research 16, 2013, pp. 351-366.
[9] G. Ferron, R. Makkouk, J. Morreale, A parametric description of orthotropic plasticity in metal sheets, International Journal of Plasticity, Vol. 10, 1994, pp. 431-449.
[10] W. Wang, X. Wei, "The effect of martensite volume and distribution on shear fracture propagation of 600-1000 MPa dual phase sheet steels in the process of deep drawing". International Journal of Mechanical Sciences, Vol. 67, 2013, pp. 100-107.
[11] A. Saaia, O.S. Hopperstad, Y. Granbom, O.-G. Lademo, "Influence of volume fraction and distribution of martensite phase on the strain localization in dual phase steels," 20th European Conference on Fracture (ECF20), Procedia Materials Science 3, 2014, pp. 900 - 905.
[12] O. Björklund, L. Nilsson, ‘Failure characteristics of a dual-phase steel sheet,” Journal of Materials Processing Technology, 214, 2014, pp. 1190–1204.
[13] L. Yaning, L. Meng, G. Jörg, W. Tomasz, “Prediction of shear-induced fracture in sheet metal forming,” Journal of Materials Processing Technology, 210, 2010, pp. 1858–1869.
[14] L.Yanshan, H. Lou, “Prediction of ductile fracture for advanced high strength steel with a new criterion: Experiments and simulation,” Journal of Materials Processing Technology 213, 2013, pp. 1284– 1302.