Correlation between fracture toughness and stretch-flangeability of advanced high strength steels

Yoon, Jae Ik; Jung, Jens; Joo, Soo Hyun; Song, Tae Jin; Chin, Kwang‐Geun; Seo, Min Hong; Kim, Sung Joon; Lee, Sunghak; Kim, Hyoung Seop

doi:10.1016/j.matlet.2016.05.145

Cited by 70 publications

(26 citation statements)

References 18 publications

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“…The diagram in Figure 10 b shows a good correlation between

derived by the uniaxial tensile test and the hole expansion ratio, which makes

also suitable to estimate qualitatively the edge-crack sensitivity of high-strength multiphase steels. Because of the link found by Frometa et al [ 30 ] and Yoon et al [ 33 ] between HER and fracture toughness,

is capable to assess qualitatively the fracture toughness at room temperature.…”

Section: Characterization and Classification In Terms Of Mechanicamentioning

confidence: 99%

“…The hole expansion test according to ISO 16630 [ 33 ] for characterizing these stretch-flangeability or rather edge-crack sensitivity itself displays several disadvantages and was therefore controversially discussed in recent research: In [ 34 ] the influences on the hole expansion ratio (HER) from the operator over the tool up to the evaluation procedure are presented. A European round robin test [ 35 ] revealed high deviations among several laboratories in testing of high strength steels because of the non-reproducible pre-damaged edge condition and the influence of several operators.…”

Section: Introductionmentioning

confidence: 99%

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Damage Mechanisms and Mechanical Properties of High-Strength Multiphase Steels

et al. 2018

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The usage of high-strength steels for structural components and reinforcement parts is inevitable for modern car-body manufacture in reaching lightweight design as well as increasing passive safety. Depending on their microstructure these steels show differing damage mechanisms and various mechanical properties which cannot be classified comprehensively via classical uniaxial tensile testing. In this research, damage initiation, evolution and final material failure are characterized for commercially produced complex-phase (CP) and dual-phase (DP) steels in a strength range between 600 and 1000 MPa. Based on these investigations CP steels with their homogeneous microstructure are characterized as damage tolerant and hence less edge-crack sensitive than DP steels. As final fracture occurs after a combination of ductile damage evolution and local shear band localization in ferrite grains at a characteristic thickness strain, this strain measure is introduced as a new parameter for local formability. In terms of global formability DP steels display advantages because of their microstructural composition of soft ferrite matrix including hard martensite particles. Combining true uniform elongation as a measure for global formability with the true thickness strain at fracture for local formability the mechanical material response can be assessed on basis of uniaxial tensile testing incorporating all microstructural characteristics on a macroscopic scale. Based on these findings a new classification scheme for the recently developed high-strength multiphase steels with significantly better formability resulting of complex underlying microstructures is introduced. The scheme overcomes the steel designations using microstructural concepts, which provide no information about design and production properties.

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“…The diagram in Figure 10 b shows a good correlation between

derived by the uniaxial tensile test and the hole expansion ratio, which makes

is capable to assess qualitatively the fracture toughness at room temperature.…”

Section: Characterization and Classification In Terms Of Mechanicamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Damage Mechanisms and Mechanical Properties of High-Strength Multiphase Steels

et al. 2018

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“…Accordingly, other researchers have used different approaches based on fracture mechanics testing for fracture resistance and local ductility assessment of AHSS. [9,14,15,[32][33][34][35] For instance, Takahashi et al [32] investigated stretch flangeability of different hot-rolled high-strength steels and found a linear correlation between J c and HER. Similar correlation between fracture toughness values and HER was observed by Casellas et al, [14] Yoon et al, [33] and Fro´meta et al [9,15] .…”

Section: Introductionmentioning

confidence: 99%

Fracture Resistance of Advanced High-Strength Steel Sheets for Automotive Applications

Frómeta

Lara

Grifé

et al. 2021

Metall Mater Trans A

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The fracture resistance of different advanced high-strength steel (AHSS) sheets for automotive applications is investigated through conventional tensile tests, fracture toughness measurements, and hole expansion tests. Different fracture-related parameters, such as the true fracture strain (TFS), the true thickness strain (TTS), the fracture toughness at crack initiation (w e i ), the specific essential work of fracture (we), and the hole expansion ratio (HER), are assessed. The specific essential work of fracture (we) is shown to be a suitable parameter to evaluate the local formability and fracture resistance of AHSS. The results reveal that fracture toughness cannot be estimated from any of the parameters derived from tensile tests and show the importance of microstructural features on crack propagation resistance. Based on the relation fracture toughness-local formability, a new AHSS classification mapping accounting for global formability and cracking resistance is proposed. Furthermore, a physically motivated fracture criterion for edge-cracking prediction, based on thickness strain measurements in fatigue pre-cracked DENT specimens, is proposed.

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“…The limited T ductility of high strength steel in contrast with the mild steel has increased the cracking issues were not possible to characterize using the conventional uniaxial tensile test experimentation. In this perspective, fracture mechanics based evaluation of the HSS will give the more understanding of the fracture behavior of the material related the crack initiation and resistance to crack propagation [2]. From the works of Yoon et al [2] and Casellas et al [3] worked on the high strength steel sheets and observed that the correlation between the edge crack resistance and fracture toughness of the material.…”

Section: Introductionmentioning

confidence: 99%

“…In this perspective, fracture mechanics based evaluation of the HSS will give the more understanding of the fracture behavior of the material related the crack initiation and resistance to crack propagation [2]. From the works of Yoon et al [2] and Casellas et al [3] worked on the high strength steel sheets and observed that the correlation between the edge crack resistance and fracture toughness of the material. The same methodology has been further investigated for the edge formability of dual phase and complex phase steel [4][5] for their resistance to crack propagation.…”

Section: Introductionmentioning

confidence: 99%

Effect of the intermediate quenching on fracture toughness of ferrite-martensite dual phase steels

Sunil¹,

Rajanna²

2020

Frattura Ed Integrità Strutturale

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The main aim of the research work is to examine the fracture toughness of the dual phase steels prepared using the intermediate quenching method. The ferrite-martensite dual phase (DP) steel is produced using low carbon micro alloyed steel by the heat treatment and intercritical quenching technique using various intercritical temperatures such as 740,760,780,800 and 820oC. The samples of the produced dual phase steel are analyzed for their microstructure using optical microscope. The fracture toughness investigations for the dual phase steel have been carried out using ASTM standard testing procedure. From the results it is observed that the fine distribution and equal volume fraction of ferrite and martensite phases at 780oC. The effect of which, the A780 steel has demonstrated excellent fracture toughness which is the result of intermediate quenching technique. The fractography analysis it is clear that the ductile initiated brittle fracture is occurred which is due to the increased hard martensite phase and the increment in the stress accumulation at the ferrite which also leads to the higher elongation.

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Correlation between fracture toughness and stretch-flangeability of advanced high strength steels

Cited by 70 publications

References 18 publications

Damage Mechanisms and Mechanical Properties of High-Strength Multiphase Steels

Damage Mechanisms and Mechanical Properties of High-Strength Multiphase Steels

Fracture Resistance of Advanced High-Strength Steel Sheets for Automotive Applications

Effect of the intermediate quenching on fracture toughness of ferrite-martensite dual phase steels

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