Damage development in low alloy TRIP-aided steels during air-bending

Reche, Delphine; Sturel, T.; Bouaziz, Olivier; Col, Audrey; Gourgues-Lorenzon, Anne-Françoise

doi:10.1016/j.msea.2011.03.042

Cited by 30 publications

(15 citation statements)

References 28 publications

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“…In the instance of poor bendability, cracks appear on the outer surface of the bend or just below it . Crack initiation typically results from either strain localization (shear band formation), and the development of micro‐voids via the following steps: 1) strain localization in the subsurface layers; 2) macroscopic shear band formation; 3) void nucleation and growth in the shear bands; and finally 4) void linkage to form cracks growing in a plane parallel to the bending axis and inclined at ≈45° to the surface. When the microstructure is homogeneous, strain is more uniformly distributed making strain localization less likely to occur .…”

Section: Discussion Of Structure – Property Relationshipsmentioning

confidence: 99%

The Influence of Microstructure on the Bendability of Direct Quenched Wear Resistant Steel

Kaijalainen

Hautamäki

Kesti

et al. 2019

steel research int.

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The influence of chemical composition and processing parameters on the microstructure and bendability of three thermomechanically rolled and directquenched wear resistant steel plates is studied. Overall, the bendability of the steels is good, but there are exceptions that are given special attention. The prior austenite condition and final microstructure is evaluated with respect to subsurface hardness and bendability. The possible effect of inclusions on bendability is taken into account. Away from the surfaces, the samples consisted mainly of auto-tempered martensite. Lowering the finishing rolling temperature (FRT) increased the total rolling reduction below the recrystallization temperature leading to pancaking of austenite and the formation of increasing fractions of polygonal ferrite (PF) and bainite near the plate surface together with an increased intensity of the shear texture component {112}<111>. Strength increased with increasing austenite pancaking provided the microstructure remained mostly martensitic. A homogeneous, largely martensitic microstructure extending across the plate thickness seemed to ensure good bendability. Microstructures that are inhomogeneous with respect to the hardness of the microconstituents, or highly ferritic, or microstructures with an intense {112}<111> shear texture component combined with elongated martensite-austenite (MA) plates in the subsurface layers resulted in the largest minimum useable bending radii.

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Section: Discussion Of Structure – Property Relationshipsmentioning

confidence: 99%

The Influence of Microstructure on the Bendability of Direct Quenched Wear Resistant Steel

Kaijalainen

Hautamäki

Kesti

et al. 2019

steel research int.

View full text Add to dashboard Cite

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“…However, columnar aligned heterogeneities associated with strong hardness differences, such as M-A islands beneath the sheet surface, act as crack initiators. 3,6,32 In the investigated material, these are mainly present in the center of the sheets. The maximal strains concentrate to the outer regions of the sheets where the ductile (granular) bainitic phase accommodates the strain.…”

Section: Initial Microstructure and Mechanical Propertiesmentioning

confidence: 96%

Effect of Morphological Differences on the Cold Formability of an Isothermally Heat-Treated Advanced High-Strength Steel

Weißensteiner

Suppan

Hebesberger

et al. 2018

JOM

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Steel sheets of Fe-0.2C-2Mn-0.2Si-0.03Ti-0.003B (m%) for the automotive industry were isothermally heat-treated, comprising austenitizing and subsequent isothermal annealing at temperatures between 300°C and 500°C. As a consequence, microstructures ranging from granular bainite over lower bainite to auto-tempered and untempered martensite were obtained. In tensile, hole expansion and bending tests, the performances in different forming conditions were compared and the changes of microstructure and texture were studied by complementary electron backscatter diffraction (EBSD) analyses. Samples with granular bainitic microstructures exhibited high total elongations but lower hole expansion ratios; in subsequent EBSD and texture analyses, evidence for inhomogeneous deformation was found. In contrast, the lath-like bainitic/martensitic microstructure showed higher strength and lower elongation to fracture. This results in a reduced bendability, but also in a high tolerance against damage induced by the shearing of edges, and, thus, allows homogeneous deformation to higher strains in the hole expansion test.

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“…Sheet metal always shows different deformation behaviors during the deformation process, such as rebounding errors [1][2][3], fracture [3][4][5][6][7], deformation failure [8][9][10], etc. Many scholars have established mathematical models to predict the above problems based on its mechanism [11,12].…”

Section: Introductionmentioning

confidence: 99%

A Fast Identification Method of Yield Strength of Materials Based on Bending Experimental Data

Duan

Tian

Zhang

et al. 2020

Metals

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Identifying the yield strength of materials quickly and accurately is the key to realizing defect prediction and digital process control on the production line. This paper focuses on identifying the material yield strength based on bending deformation, analyzing the influence of different die fillets, punch fillets, and die spans on the curve shapes, determining the reasonable dimensions of the device, and developing them. Two methods for rapidly extracting the yield load are proposed—the window vector method (WV) and the fitting residual method (FR)—and compared with the double secant line method (CWA) and the one tenth thickness method (t/10). Because there is no direct correspondence between the yield load and the material performance parameters, the relevant equations were fitted using the experimental data. The linear correlation between load and yield strength determined by these four methods was close to 0.99. Finally, four kinds of sheets with high, medium and low yield strength were tested and compared with the observed results. The result shows that when the yield strength is small, the average error and the relevant model dispersion will increase. As the yield strength increases, the biases increase gradually. The prediction errors based on the t/10, WV, and FR methods were all below 4%.

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Damage development in low alloy TRIP-aided steels during air-bending

Cited by 30 publications

References 28 publications

The Influence of Microstructure on the Bendability of Direct Quenched Wear Resistant Steel

The Influence of Microstructure on the Bendability of Direct Quenched Wear Resistant Steel

Effect of Morphological Differences on the Cold Formability of an Isothermally Heat-Treated Advanced High-Strength Steel

A Fast Identification Method of Yield Strength of Materials Based on Bending Experimental Data

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