Experimental Analysis of Forming Limits and Thickness Strains of DP600-800 Steels

Abstract:

In this work, the plastic behavior of cold-rolled zinc coated dual-phase steel sheets DP600 and DP800 grades is firstly investigated by means of uniaxial tensile and Forming Limit Curve (FLC) testing. The uniaxial tensile tests were carried out at 0^o, 45^o and 90^o angular orientations with respect to the rolling direction to evaluate the mechanical properties and the plastic anisotropy Lankford r-values. The forming limit strains are defined according to Nakajima’s procedure. Thickness measurements of tested Nakajima’s samples cut perpendicular to the fracture allowed to identify a rapid decrease of the strain, which governs the plastic instability that preceded the fracture in the drawing region of the FLC. Optical metallographic and scanning electron microscopy techniques helped to characterize and distinguish the orientation of rotated grains and flat fractured surface (ductile shear failure in blank specimens close to plane-strain tension) from no grain rotations and rough fractured surface (ductile tensile fracture in blank geometries in the biaxial stretching domain).

• Periodical: Applied Mechanics and Materials (Volume 835)
• Pages: 230-235
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.835.230
• Online since: May 2016
• Authors: Marcelo Costa Cardoso, Alexandre de Melo Pereira, Fabiane Roberta Freitas da Silva, Luciano Pessanha Moreira*
• Keywords: Dual-Phase Steels, Ductile Shear Fracture, Ductile Tensile Fracture, Limit Strains

References

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DOI: 10.3403/30150423u