Measurements of anisotropic yielding, bauschinger and transient behavior of automotive dual-phase steel sheets

Kim, Dae-Yong; Lee, Myoung‐Gyu; Kim, Chongmin; Wenner, Michael L.; Wagoner, R. H.; Barlat, Frédéric; Chung, Kwansoo; Youn, Jae Ryoun; Kang, Tae Jin

doi:10.1007/bf03027256

Cited by 29 publications

(13 citation statements)

References 10 publications

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“…[16][17][18][19] Despite the longstanding investigations into the effective grain size of acicular ferritic, bainitic, martensitic, or multiphase steels, there still remain many controversies. [19][20][21][22][23][24][25][26] These studies on the correlation between microstructure and low-temperature toughness have been mostly limited to the ductile-brittle transition temperature and the absorbed energy obtained from Charpy impact tests, and the studies into the effects of microstructure and effective grain size, steel properties, and test conditions on DWTT properties are rarely touched. In the present study, thus, pipeline steels having various microstructures were fabricated by varying alloying elements and rolling conditions, and the Charpy impact test and DWTT were conducted on them in order to evaluate toughness.…”

Section: Discussionmentioning

confidence: 99%

“…[13] The toughness is largely affected by microstructural factors, while the transition temperature is associated with an overall domain widely known as an effective grain size. [13,[15][16][17][18][19][20][21][22][23][24][25][26] In the present study, high-strength, high-toughness X70 pipeline steel specimens were fabricated by varying alloying elements and rolling conditions. Charpy impact test and pressed notch DWTT were conducted on them in order to investigate effects of microstructure on fracture toughness and transition temperature.…”

Section: Introductionmentioning

confidence: 99%

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Correlation of microstructure and fracture properties of API X70 pipeline steels

Hwang

Kim

Lee

et al. 2005

Metall Mater Trans A

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Effects of microstructure on fracture toughness and transition temperature of high-toughness X70 pipeline steels were investigated in this study. Three types of steels were fabricated by varying alloying elements such as C, Cu, and Mo, and their microstructures were varied by rolling conditions such as finish rolling temperature and finish cooling temperature. Charpy V-notch (CVN) impact tests and pressed notch drop-weight tear tests (DWTT) were conducted on the rolled steel specimens. The Charpy impact test results indicated that the specimens rolled in the single-phase region of the steel containing a reduced amount of C and Mo had the highest upper shelf energy (USE) and the lowest energy transition temperature (ETT) because of the appropriate formation of acicular, quasipolygonal, or polygonal ferrite and the decreased fraction of martensite-austenite constituents. Most of the specimens rolled in the single-phase region also showed excellent DWTT properties as the percent shear area (pct SA) well exceeded 85 pct, irrespective of finish cooling temperatures, while their USE was higher than that of the specimens rolled in the two-phase region. Thus, overall fracture properties of the specimens rolled in the single-phase region were better than those of the specimens rolled in the two-phase region, considering both USE and pct SA.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Correlation of microstructure and fracture properties of API X70 pipeline steels

Hwang

Kim

Lee

et al. 2005

Metall Mater Trans A

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“…The material properties of DP-steel have been previously measured as summarized in the work by Kim et al [16]. The experimental procedures and material properties of DP-steel are briefly summarized here.…”

Section: Materials Propertiesmentioning

confidence: 99%

“…However, since thin sheets are prone to buckle under compression, compression tests have been performed by providing guides along the both sides of the sheet specimen on which clamping forces are applied [16]. For the Bauschinger and transient behavior during unloading, uni-axial tension/ compression (pre-tensile straining before compression) tests have been performed, while hardening behavior has been measured using uni-axial tension tests.…”

Section: Hardening Behavior With Unloadingmentioning

confidence: 99%

Effect of hardening laws and yield function types on spring-back simulations of dual-phase steel automotive sheets

et al. 2006

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In order to simulate the spring-back of DP-steel automotive sheets, the effect of hardening laws and yield function types has been studied based on finite element simulations performed for 2-D draw bending and S-rail tests. Specifically, the performance of the combined isotropic-kinematic hardening based on the modified Chaboche model was compared with those of the pure isotropic hardening and kinematic hardening laws, along with the non-quadratic anisotropic yield (Yld2000-2d) and Mises yield functions. As for the 2-D draw bending test, numerical results were compared with experimental results for verification purposes.

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“…4(a)), such crossover was not observed up to the true strain of 1.2, but was expected to occur with further increasing of strain. The flow stress crossover or convergence before and after drawing can be explained in terms of the two combined effects of pre-straining by drawing and the Bauschinger effect 14,15) during compression. As depicted in Fig.…”

Section: Compression Propertiesmentioning

confidence: 99%

Comparison of Cold Formability of Cold Drawn Non-heat-treated Steels Having Similar Strength

Park

Lee

et al. 2005

ISIJ Int.

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The cold formability of the drawn non-heat-treated steels, i.e. dual phase (DP) steel, low Si steel and ultra low carbon bainitic (ULCB) steel, was examined in terms of the deformation resistance and the forming limit. The present investigation was aimed at elucidating the effect of drawing on the cold formability of non-heat-treated steels which is directly affected by drawing since no heat treatment are involved during forming processes for them. A special care was taken for the present steels to exhibit the similar strength after drawing, so eliminating the strength effect. The present steels after drawing revealed the elastic-near perfect plastic behavior in compression. After drawing, the low Si steel exhibited the lowest deformation resistance estimated by the absorbed energy during deformation. In case of the forming limit in terms of the critical strain under which no cracking occurs during the upsetting test of the drawn steels, the low Si steel and the ULCB steel were better than the conventional heat-treated steel. Accordingly, among several nonheat-treated steels which can replace the conventional heat-treated steel as forging steels, the low Si steel seems to exhibit the best performance if they have the similar strength. The compressive deformation behavior of the present drawn non-heat-treated steels was discussed in association with the strain hardened state and the Bauschinger effect developed by drawing. In addition, their cold formability was explained by the plastic incompatibility between the constituent phases of each steel.KEY WORDS: cold formability; drawing; non-heat treated steels; dual phase steel; low-Si steels; ultra low carbon bainitic steels; tensile and compression properties.

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Measurements of anisotropic yielding, bauschinger and transient behavior of automotive dual-phase steel sheets

Cited by 29 publications

References 10 publications

Correlation of microstructure and fracture properties of API X70 pipeline steels

Correlation of microstructure and fracture properties of API X70 pipeline steels

Effect of hardening laws and yield function types on spring-back simulations of dual-phase steel automotive sheets

Comparison of Cold Formability of Cold Drawn Non-heat-treated Steels Having Similar Strength

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