Open hole tensile tests for the determination of the edge-crack sensitivity of sheared holes dependent on specimen geometry, cutting parameters, and the notch factor

Feistle, Martin; Pätzold, Isabella; Golle, Roland; Volk, Wolfram

doi:10.1016/j.promfg.2019.02.156

Cited by 8 publications

(5 citation statements)

References 3 publications

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“…Several alternatives to the HEC test have been proposed in the literature, including the sheared edge tensile test [31,32], open hole tensile test [33], side bending test [34], and in-plane bending test [35]. Among these tests, the in-plane bending test is particularly advantageous since it allows for both global examination of edge performance via a momentcurvature diagram and local evaluation via digital image correlation.…”

Section: Punchmentioning

confidence: 99%

Initiation and growth of edge cracks after shear cutting of dual-phase steel

Khalilabad

Perdahcioglu

Atzema

et al. 2023

Int J Adv Manuf Technol

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Dual-phase steels suffer from low edge ductility, which limits their formability. In this study, an in-plane bending test is used to investigate the initiation and evolution of edge cracks. The edges of samples were prepared by shear cutting and afterwards further deformed by the in-plane bending test. Void distribution and non-uniform plastic deformation were explored with the help of scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) analysis and microhardness measurement in different regions of the material edge. The extent of micro-cracks was revealed by microcomputed tomography (µCT) scan. The result shows that the blanking process creates inhomogeneous void distribution in the thickness direction. As the deformation increases during the subsequent in-plane bending test, the micro-cracks initiate at the burr region and grow towards the rollover region. Once they entirely pass the thickness of the material, they grow further, away from the edge. High roughness, plastic deformation, and void volume fraction were observed at the burr region, triggering crack initiation. The in-plane bending test successfully distinguished the dominant mechanism behind edge cracking.

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Section: Punchmentioning

confidence: 99%

Initiation and growth of edge cracks after shear cutting of dual-phase steel

Khalilabad

Perdahcioglu

Atzema

et al. 2023

Int J Adv Manuf Technol

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“…To investigate the influence of the shear-cutting parameters on edge characteristics and consequently on the failure behaviour of the stamped edges in forming related operations, various experimental tests have been developed, such as Hole-Expansion Test (HET) [ISO 16630], Diabolo-test [19] or Half-dome-test [1]. The tensile test with one-sided stamped edge [7] and Hole-Tensile-Test [8][9][10][11] allow free loading of the stamped edge (e.g. not involving tool contact and friction) and thus better represent the loading situation in a safety component break load test.…”

Section: Literature On Stamped Edge Stretchabilitymentioning

confidence: 99%

Modelling stamped edges in FEM breakage analyses of high-strength steel safety components

Lingbeek

Schalk-Kitting

Gruschka

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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The development process for new safety components includes break load tests, where the component undergoes very large strains. Besides the mechanical properties of the steel, which are changed by the forming process, the break load depends on the quality of the stamped edges. Target of this paper is to investigate whether a hole-tensile test with a stamped hole can demonstrate the effects of stamped-edge quality on the load bearing capacity – and secondary, how such a test procedure can be reproduced with a multi-scale FEM procedure. A series of Hole Tensile Tests (HTT) has been performed with a HSLA steel grade. Here, only minor differences in break load and total elongation were found. The local strain just prior to breakage at the edge of the stamped hole shows remarkably high values, but little difference is found when comparing a machined sample to stamped samples. The multi-scale FEM approach was demonstrated using literature data for dual-phase steel, which is known to be more sensitive to edge cracks. Indeed, a stamped edge, which includes significant hardening and pre-damage, shows earlier fracture in this FEM calculation – however, the crack propagation, which is needed to capture the full breakage of the HTT sample, is not modelled correctly – this limits the application of the method on safety components.

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“…The initial geometry and the process steps for manufacturing the specimens are shown in Figure 3 b). The second tool, shown in Figure 4 allows the centric placement of a hole in the very middle of the specimen for the hole tensile test as speciőed in [20]. Both tools were operated on a high-performance automatic stamping press BSTA 1600 from Bruderer AG, Switzerland, with a maximum press force of 1600 kN.…”

Section: Shear Cutting Tools and Pressesmentioning

confidence: 99%

Blanking of Stainless Steel

Pätzold

Tröber

Welm

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Slug pulling, adhesion formation and edge fracture are major challenges in the sheet metal processing industry. They lead to a strong reduction in part quality, process stability as well as profitability. In this study, investigations are carried out on stainless steel X5CrNi18-10 to address the previous mentioned challenges. While slug pulling and edge fracture strongly depend on the geometric characteristics of active elements as well as the selection of process parameters, adhesion formation is mainly determined by temperature and thermoelectric currents. In this publication, the influence of the die channel geometry on the slug pulling effect and the part quality is investigated. Furthermore, the temperature profile over the shear cutting process as well as the resulting thermoelectric currents are determined for the test material. The relationship between edge crack sensitivity, shear cutting parameters and strategies is examined. These investigations thus form the basis for an improved understanding of the shear cutting of stainless steel.

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Open hole tensile tests for the determination of the edge-crack sensitivity of sheared holes dependent on specimen geometry, cutting parameters, and the notch factor

Cited by 8 publications

References 3 publications

Initiation and growth of edge cracks after shear cutting of dual-phase steel

Initiation and growth of edge cracks after shear cutting of dual-phase steel

Modelling stamped edges in FEM breakage analyses of high-strength steel safety components

Blanking of Stainless Steel

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