Failure during Sheared Edge Stretching of Dual-Phase Steels

Lévy, Bernard; Gibbs, M.R.J.; Tyne, C. J. Van

doi:10.1007/s11661-013-1718-7

Cited by 33 publications

(15 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The martensite and MA grains could not be clearly distinguished as well as ferrite and bainite due to the high level of deformation caused by the punching process. The martensite and MA will be called “hard microconstituents” and ferrite and bainite “soft microconstituents.” The LCR and HCR samples showed microvoids nucleated at grains fractured of hard microconstituent and hard/soft microconstituent interfaces in the shear and fracture zones as reported for dual phase steels and complex phase steels . In addition, a nucleated crack at hard/soft microconstituent interfaces that propagated through the interfaces following the banded microstructure direction can be observed.…”

Section: Resultssupporting

confidence: 70%

“…The punching process shows a lower HER compared to machining and wire cutting as a result of strain hardening and formation of microvoids and microcracks at the hole edge . Microvoid nucleation occurs at the ferrite/martensite interfaces and through martensite cracking . In addition, microvoid nucleation near the hole edge‐punched occurred by fracture of large TiN particles and at bainite/martensite interfaces …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure, Crystallographic Texture, and Stretch‐Flangeability of Hot‐Rolled Multiphase Steel

Moura

Ferreira

Martins

et al. 2020

steel research int.

View full text Add to dashboard Cite

The microstructure, crystallographic texture, strain hardening in the hole edge‐punched and stretch‐flangeability of hot‐rolled multiphase sheet steel is investigated by scanning electron microscopy, electron backscatter diffraction, and microhardness measurements. The results show that the strain hardening in the hole edge‐punched is not the main factor that influences the hole expansion ratio. The bainite fraction, average grain area, and kernel average misorientation distribution mean are microstructure factors that improve the hole expandability and reduce the effect of strain hardening in the hole edge‐punched on the hole expansion ratio. The crystallographic texture affects the hole expandability. The high intensity of {332}<113>α and {111}<112>α components that have higher normal anisotropy (rtrue¯) also reduces the effect of strain hardening at the hole edge‐punched. The cracks propagate through the interfaces following the banded microstructure direction at the hole edge‐punched during the punching process. The gamma distribution analysis of the kernel average misorientation distribution indicates that there are different energy transfer (β parameter) and dislocation densities due to different cooling rates.

show abstract

Section: Resultssupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Microstructure, Crystallographic Texture, and Stretch‐Flangeability of Hot‐Rolled Multiphase Steel

Moura

Ferreira

Martins

et al. 2020

steel research int.

View full text Add to dashboard Cite

show abstract

“…16) The hole expansion ratio (HER) of multiphase steel grades strongly depends on the strength ratio between the different microstructure constituents [17][18][19][20][21][22] and on their geometrical arrangement. 17,20) The possible presence of retained austenite, depending on whether it has transformed or not during the punching prior to the hole expansion test, may also affect the hole expansion ratio. [23][24][25] However, most of the results reported in literature have been obtained on DP, TRIP or Complex Phase grades.…”

Section: On the Effect Of Qandp Processing On The Stretch-flange-formabmentioning

confidence: 99%

On the Effect of Q&P Processing on the Stretch-flange-formability of 0.2C Ultra-high Strength Steel Sheets

et al. 2018

View full text Add to dashboard Cite

Quenching and Partitioning (Q&P) has been proposed as a novel heat treatment to produce cold rolled sheets with excellent strength and sufficient formability for cold stamping. The impact of Q&P processing on microstructure and tensile properties has been extensively studied in contrast to the lower attention devoted to its effect on stretch-flange-formability. In this study, the stretch-flange-formability of Q&P microstructures is investigated by means of hole expansion tests carried out on punched holes. The balance between tensile properties and hole expansion ratios (HER) is discussed and compared to three model microstructures: biphasic dual-phase (DP), single phase quenched & tempered (Q&T) and quenched & austempered (QAT). It is shown that Q&P microstructures exhibit a better combination of tensile ductility and stretch-flange-formability than fully martensitic (excellent HER but poor tensile ductility) and austempered microstructures (good ductility but poor HER). The study of the impact of the Q&P parameters demonstrates that stretch-flange-formability is further promoted by choosing low quench temperatures and long partitioning times. The hole expansion properties are linked to the hardness gradients in the microstructure, evaluated by nanohardness mapping. The narrower nanohardness distribution in the Q&P microstructure leads to better hole expansion ratios compared to bainitic microstructures obtained by austempering, where the presence of hard M/A blocks is unavoidable.

show abstract

“…4,[14][15][16] Generally, sheared holes lead to a lower HER than machined holes due to the reduced ductility of the workhardened shear-affected zone and the possibility of pre-initiated voids or cracks at the sheared edge. 4 A machined hole removes the shear-affected zone, generally resulting in improved HER.…”

Section: Effects Of Edge Conditions and Punch Geometry On Hermentioning

confidence: 99%

“…[4][5][6][7][8][9][10][11][12][13][14][15][16][17] HET can be performed with conical [4][5][6][7][8] and flatbottom punches, 4,9-13 as well as different hole preparation methods (for example, sheared or machined). 4,[14][15][16] Studies have shown that materials tested with a conical punch generally have a higher hole expansion ratio (HER) than the same material tested with a flat-bottom punch. 4,12,[18][19][20] This difference has been attributed to the bending component introduced by the conical punch creating a material constraint that delays failure.…”

Section: Introductionmentioning

confidence: 99%

Effects of Testing Method on Stretch-Flangeability of Dual-Phase 980/1180 Steel Grades

Madrid

Tyne

Sadagopan

et al. 2018

JOM

View full text Add to dashboard Cite

Failure during Sheared Edge Stretching of Dual-Phase Steels

Cited by 33 publications

References 31 publications

Microstructure, Crystallographic Texture, and Stretch‐Flangeability of Hot‐Rolled Multiphase Steel

Microstructure, Crystallographic Texture, and Stretch‐Flangeability of Hot‐Rolled Multiphase Steel

On the Effect of Q&P Processing on the Stretch-flange-formability of 0.2C Ultra-high Strength Steel Sheets

Effects of Testing Method on Stretch-Flangeability of Dual-Phase 980/1180 Steel Grades

Contact Info

Product

Resources

About