Mechanical properties of ultrafine grained ferritic steel sheets fabricated by rolling and annealing of duplex microstructure

Okitsu, Yoshitaka; Takata, Naoki; Tsuji, Nobuhiro

doi:10.1007/s10853-008-2971-9

Cited by 36 publications

(32 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Okitsu et al 35,36) report that when a DP steel is cold rolled and optimally heat treated, an ultrafine-grained microstructure is obtained where fine cementite is dispersed in ferrite. They also say that an ultrafine-grained microstructure is evolved in DP steel with an equivalent plastic strain smaller than the severe plastic deformation claimed to produce finegrained steels.…”

Section: S-tem Observation Of Dislocation Structure Inmentioning

confidence: 99%

Quantification of Large Deformation with Punching in Dual Phase Steel and Change of its Microstructure –Part I: Proposal of the Quantification Technique of the Punching Damage of the Dual Phase Steel

Yokoi¹,

Shuto²,

Ikeda

et al. 2016

ISIJ Int.

View full text Add to dashboard Cite

Dual Phase (DP) steel is used in automotive body parts for weight saving and crashworthiness, however there is an issue of DP steel in low stretch flange ability evaluated by hole expanding tests. In order to improve stretch flange ability of DP steel, it is important to estimate the damage of punching quantitatively and to clarify the change of microstructure before and after punching because the hole expansion ratio is decided in the ductility remained after pre-strain equivalent to punching. Therefore we tried to measure the damage of punching by unique techniques of Electron Backscatter Diffraction (EBSD), nano-indentation and micro-tensile testing and to observe fracture surface by Scanning Transmission Electron Microscope (STEM). Average EBSD-Kernel Average Misorientation (KAM) value and pre-strain damage have strong correlation, thus average KAM value can become the index of the damage. The nanohardness and tensile strength using micrometer-sized specimens increased with increasing average KAM value in the ferritic phase as approaching the punching edge. A shear type fracture occurred without necking in the specimen cut out in the area of the edge. The ultrafine-grained ferritic microstructure was observed in the sample cut out in the same area with STEM. It seems that the ductility loss of the punched DP steel was probably attributed to localized strain into the ultrafine-grained ferritic microstructure.

show abstract

Section: S-tem Observation Of Dislocation Structure Inmentioning

confidence: 99%

Quantification of Large Deformation with Punching in Dual Phase Steel and Change of its Microstructure –Part I: Proposal of the Quantification Technique of the Punching Damage of the Dual Phase Steel

Yokoi¹,

Shuto²,

Ikeda

et al. 2016

ISIJ Int.

View full text Add to dashboard Cite

show abstract

“…Small additions of carbon (C) and manganese (Mn) can significantly influence on mechanical, structural, and electrical properties of steels, such as its tensile strength, 1) ultragrain refinement, 2) and corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

“…4,5) Accurate measurements of the C concentration and location in Fe alloys have been carried out, which are important for the detailed understanding of the effect of small C concentration. 6) Although the transformation of Fe and Fe alloys with small C and Mn contents has been studied extensively at Non-Contact Measurement of Thermophysical Properties of Fe, Fe-C, and Fe-C-Mn Alloys in Solid, Supercooled, and Stable Liquid Phases Sangho JEON, 1,2) Dong-Hee KANG, 3) Shin Hwan KANG, 4) Shin Eon KANG, 4) Junpei T. OKADA, 5) Takehiko ISHIKAWA, 5) Sooheyong LEE 1) and Geun Woo LEE 1,2) * (Received on September 11, 2015; accepted on December 15, 2015) High temperature thermophysical properties of Fe and Fe alloys with small additions of C and Mn are reported using electrostatic levitation, for the first time. Thermophysical property measurements were carried out in wide temperature ranges from 800 K to 1 850 K, including solids, supercooled, and stable liquids.…”

Section: Introductionmentioning

confidence: 99%

Non-Contact Measurement of Thermophysical Properties of Fe, Fe–C, and Fe–C–Mn Alloys in Solid, Supercooled, and Stable Liquid Phases

Jeon

Kang

et al. 2016

ISIJ Int.

View full text Add to dashboard Cite

“…The steel A is a low-C steel prepared for fabricating FC microstructures with various ferrite grain sizes from sub-micrometer to micrometer region. A new and simple route composed of rolling and annealing of a duplex microstructure 7,9) was applied to the steel A. Steel ingots prepared by vacuum melting was hot-rolled in austenite region, air-cooled to 540°C corresponding to the intercritical region of ferrite and austenite, and then water-cooled to room temperature for obtaining a duplex microstructure of ferrite and martensite.…”

Section: ¹1mentioning

confidence: 99%

Effect of Ferrite Grain Size on Dynamic Tensile Properties of Ultrafine Grained Low Carbon Steels with Various Chemical Compositions

Okitsu

Tsuji

2014

Mater. Trans.

Self Cite

View full text Add to dashboard Cite

The effects of ferrite grain size on dynamic tensile properties of low carbon steels with various chemical compositions are shown. The strain rate dependence of flow stress, represented by the difference between flow stresses at high and low strain rates, ¦·, was the highest in the interstitial free (IF) steel having ferrite single-phase microstructure and the 0.1% C-steel having ferritecementite (FC) microstructure. The ¦· decreased when P and Mn were added. In all the steels used, the ¦· was almost constant or decreased only slightly when the ferrite grains were refined down to 24 µm, and it decreased significantly by further grain refinement down to sub-micrometer region. The FC and ferrite singlephase microstructures strengthened mainly by grain refinement of ferrite showed higher dynamic absorbed energy compared with the other steels strengthened by alloy addition.

show abstract

Mechanical properties of ultrafine grained ferritic steel sheets fabricated by rolling and annealing of duplex microstructure

Cited by 36 publications

References 13 publications

Quantification of Large Deformation with Punching in Dual Phase Steel and Change of its Microstructure –Part I: Proposal of the Quantification Technique of the Punching Damage of the Dual Phase Steel

Quantification of Large Deformation with Punching in Dual Phase Steel and Change of its Microstructure –Part I: Proposal of the Quantification Technique of the Punching Damage of the Dual Phase Steel

Non-Contact Measurement of Thermophysical Properties of Fe, Fe–C, and Fe–C–Mn Alloys in Solid, Supercooled, and Stable Liquid Phases

Effect of Ferrite Grain Size on Dynamic Tensile Properties of Ultrafine Grained Low Carbon Steels with Various Chemical Compositions

Contact Info

Product

Resources

About