Enhanced upper shelf energy by ultrafine elongated grain structures in 1100MPa high strength steel

Jafari, Meysam; Kimura, Yuuji; Tsuzaki, Kaneaki

doi:10.1016/j.msea.2011.11.007

Cited by 24 publications

(22 citation statements)

References 23 publications

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“…4 shows the variation in the tensile properties at room temperature as a function of P concentration. As previously reported for the 0.001% and 0.053% P steels [19][20][21]23], it was characteristic that all the QT samples exhibited typical continuous yielding behavior. However, irrespective of the P addition, the sharp yield point phenomenon was observed for all the TF samples, and the  y approximately corresponded to the upper yield stress of the TF samples.…”

Section: Microstructuresupporting

confidence: 82%

“…The carbide particles of 8 the TF sample appear to be more spherical than those of the QT sample, and their long axes were observed to be almost aligned to the RD of the TF sample. It was confirmed that the microstructural features of the TF samples with an addition of 0.093% P, including the transverse grain size, grain shape, <110>//RD fiber texture, and carbide particle distribution were almost comparable to those of the 0.001% P and 0.053% P steels [19][20][21][22][23]. Hence, the addition of 0.093% P has little influence on the evolution of the UFEG structure during the WTF.…”

Section: Microstructural Characterizationmentioning

confidence: 64%

“…The reduction in area owed to the multi-pass hot rolling was about 80%. Table 1 lists the chemical compositions of the steels, namely 0.018% P steel, 0.068% P steel, and 0.093% P steel, as analyzed after hot-rolling, along with those of the 0.001% P [19,[21][22][23] and 0.053% P [19][20][21][22] steels as a reference. The chemical compositions are similar to those of 5 the high-strength JIS SCM 440 (AISI 4140) steel, with the exception of the high P concentration.…”

Section: Materials Preparationmentioning

confidence: 99%

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Delamination toughening assisted by phosphorus in medium-carbon low-alloy steels with ultrafine elongated grain structures

Min

Kimura

et al. 2016

Materials Science and Engineering: A

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The effect of phosphorus (P) on delamination toughening was examined for 0.4%C-1%Cr-0.7%Mn-0.2%Mo steels (mass%) comprised of ultrafine elongated grain (UFEG) structures with strong <110>//RD fiber textures. The UFEG structures evolved through the plastic deformation of tempered martensitic structures by multi-pass caliber rolling at a temperature of 773 K (warm tempforming, WTF). The addition of P, up to 0.093% (mass%), had little influence on the evolution of the UFEG structure and the strength of the steels.Although the tensile ductility and upper-shelf energy showed a slight tendency to decrease as 2 the P concentration increased from 0.001% to 0.093%, the delamination perpendicular to the notch orientation of the impact specimens was pronounced over a wider temperature range. As a result of delamination, the 0.093% P-doped steel exhibited a significant inverse temperature dependence of toughness at temperatures from 250 K to 350 K. The delamination toughening was dominated by the UFEG structure, and further assisted by the phosphorus segregation. It was considered that the formation of distinct P segregation bands, which presented a structure consisting of brittle and ductile layers, may be especially effective in accelerating delamination and improving toughness in P-doped steel with an UFEG structure.

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Section: Microstructuresupporting

confidence: 82%

Section: Microstructural Characterizationmentioning

confidence: 64%

Section: Materials Preparationmentioning

confidence: 99%

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Delamination toughening assisted by phosphorus in medium-carbon low-alloy steels with ultrafine elongated grain structures

Min

Kimura

et al. 2016

Materials Science and Engineering: A

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“…However, delamination in the ductile region is reported to reduce the impact energy [34], and leads to a cleavage behavior parallel to rolling plane during the impact process [41]. Fig.…”

Section: Delamination Crystallographic Texture and Impact Energy In mentioning

confidence: 99%

Relationships among crystallographic texture, fracture behavior and Charpy impact toughness in API X100 pipeline steel

Yang

Tan

et al. 2015

Materials Science and Engineering: A

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“…13 Yield stress vs Charpy absorbed impact energy at ambient temperature. Here, BiR and UnR denote ultrafine-grained (UFG) steel fabricated by warm rolling (38) , TF and AR denote UFG steel fabricated by warm caliber rolling (34), (39) , QT is quench and tempered steel (39) .…”

mentioning

confidence: 99%

Toughening of Low-Carbon Steel by Ultrafine-Grained Structure

Inoue

Kimura²

2013

Trans.JSME, Ser.A

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A low-carbon steel bar with an ultrafine elongated grain (UFEG) structure and an ultrafine exiaxed grain (UFG) structure was fabricated by multipass caliber rolling at 500℃ and subsequent annealing at 500, 550, 600 and 650℃.The Charpy impact and static tensile tests were conductued at ambient temperature. The microstructures in the as-rolled bar and the annealed bars until 600℃ consisted of an UFEG structure with a strong -fiber texture. The both strength and impact energy increased in the as-rolled bar consisting of spheroidal cementite particles that distributed uniformly in the elongated ferrite matrix of transverse grain size of 0.73 m. In the bars with the UFEG structure, many microcracks during an impact tests were observed near the main crack with fine dimples, and they were classified into two types: one normal to the striking direction (SD) and one with an angle of 45º to the SD. The occurrence of such brunching cracks corresponded to the spatial distribution of {100} cleavage planes and boundaries of the elongated grains. This tendency disappeared as annealing temperatures increased. The as-rolled bar exhibited the best strength-toughness balance in the annealed bars, conventional carbon steels and some UFG steels. In conclusion, the strength-toughness balance is improved by refining crystal grains and controlling their shape and orientation.

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Enhanced upper shelf energy by ultrafine elongated grain structures in 1100MPa high strength steel

Cited by 24 publications

References 23 publications

Delamination toughening assisted by phosphorus in medium-carbon low-alloy steels with ultrafine elongated grain structures

Delamination toughening assisted by phosphorus in medium-carbon low-alloy steels with ultrafine elongated grain structures

Relationships among crystallographic texture, fracture behavior and Charpy impact toughness in API X100 pipeline steel

Toughening of Low-Carbon Steel by Ultrafine-Grained Structure

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