Abstract
Failure during sheared edge stretching of sheet steels is a serious concern, especially in advanced high-strength steel (AHSS) grades. The shearing process produces a shear face and a zone of deformation behind the shear face, which is the shear-affected zone (SAZ). A failure during sheared edge stretching depends on prior deformation in the sheet, the shearing process, and the subsequent strain path in the SAZ during stretching. Data from laboratory hole expansion tests and hole extrusion tests for multiple lots of fourteen grades of steel were analyzed. The forming limit curve (FLC), regression equations, measurement uncertainty calculations, and difference calculations were used in the analyses. From these analyses, an assessment of the primary factors that contribute to the fracture during sheared edge stretching was made. It was found that the forming limit strain with consideration of strain path in the SAZ is a major factor that contributes to the failure of a sheared edge during stretching. Although metallurgical factors are important, they appear to play a somewhat lesser role.
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Acknowledgments
The authors thank the Auto/Steel Partnership in Southfield, MI, USA for partial support of this work. The authors also thank personnel at Ispat-Inland (now Arcelor Mittal) Research Laboratory in East Chicago, IL, USA for their work on the American Iron and Steel Institute project (Ref 14).
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Levy, B., Van Tyne, C. Failure During Sheared Edge Stretching. J. of Materi Eng and Perform 17, 842–848 (2008). https://doi.org/10.1007/s11665-008-9218-4
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DOI: https://doi.org/10.1007/s11665-008-9218-4