Ultragrain refinement of plain low carbon steel by cold-rolling and annealing of martensite

Ueji, Rintaro; Tsuji, Nobuhiro; Minamino, Yoritoshi; Koizumi, Yuichiro

doi:10.1016/s1359-6454(02)00260-4

Cited by 336 publications

(202 citation statements)

References 25 publications

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“…However, in the martensite process, the martensite starting microstructure enhanced quick grain subdivision, so that only conventional 50% cold-rolling could realize the ultrafine grain subdivision. The present authors [18] have suggested that one of the main reasons for the quick grain subdivision is that the martensite starting structure has a kind of fine grained structure in the as-transformed state, although the detailed mechanism of the quick grain subdivision have not been clarified yet. Furthermore, only 50% cold-rolling was used in the previous studies [17,18], so that the effect of rolling reduction (strain) on the deformed and final microstructure in the martensite process has not yet been studied.…”

Section: Introductionmentioning

confidence: 83%

“…The 50% coldrolling of martensite mainly developed the ultrafine lamellar structure, which is typical for the severely deformed materials, and the subsequent annealing at warm temperature around 500 8C brought the change from the lamellar structure to the equiaxed ultrafine grains with mean grain size of 180 nm [18]. The previous study [19] also indicated that the formation mechanism of the lamellar structure is a kind of grain subdivision: the deformation induced grain boundaries subdivide the initial grains to ultrafine regions.…”

Section: Introductionmentioning

confidence: 87%

“…The quenched sheet showed typical lath martensite structure. The prior austenite grain size estimated from the microstructure after quenching was 270 mm [18]. The quenched sheets were cold-rolled to a reduction of 25, 50 or 70% (1 vM ¼ 0:3; 0.8 or 1.5) by 1 pass, 3 passes and 25 passes, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, the present authors have invented a new route to fabricate the UFG steels, named the martensite process, which does not need SPD [17,18]. The key of this process is to use martensite structure as a starting microstructure.…”

Section: Introductionmentioning

confidence: 99%

“…The present authors [18] have been studied that the microstructural change during the martensite process in case of the 50% cold rolling (equivalent von Mises strain: 1 vM ¼ 0:8) in 0.13% C plain carbon steel. The 50% coldrolling of martensite mainly developed the ultrafine lamellar structure, which is typical for the severely deformed materials, and the subsequent annealing at warm temperature around 500 8C brought the change from the lamellar structure to the equiaxed ultrafine grains with mean grain size of 180 nm [18].…”

Section: Introductionmentioning

confidence: 99%

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Effect of rolling reduction on ultrafine grained structure and mechanical properties of low-carbon steel thermomechanically processed from martensite starting structure

Ueji

Tsuji

Minamino

et al. 2004

Science and Technology of Advanced Materials

109

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The present authors have invented a novel and simple thermomechanical processing to realize the ultrafine grained microstructure in carbon steels. The key of the process is to start from martensite structure. In the previous study, it has been clarified that conventional coldrolling to a reduction in thickness of only 50% (equivalent strain of 0.8) and subsequent annealing at warm temperature around 500 8C fabricates the multi-phased ultrafine grained structure composed of the ultrafine ferrite grains with mean grain size of 180 nm, uniformly precipitated nano cementite and tempered martensite. In this study, the effect of the rolling reduction ranging from 25 to 70% (equivalent strains of 0.3-1.5) on the ultrafine grained structure and the mechanical properties of the plain low-carbon steel (Fe -0.13 wt% C) processed from martensite starting structure was studied. In the as-deformed specimen, the area fraction of the region showing the lamellar structure, which is typical for severely rolled metals, increased with increasing the rolling reduction and the strength also increased. After annealing at warm temperature around 500 8C, the multi-phased ultrafine grained microstructures were obtained in all the examined rolling reductions. The area fraction of the region showing the ultrafine ferrite grains increased with increasing the rolling reduction. At higher temperature, conventional recrystallization took place, and the recrystallization temperature became lower with increasing the reduction. Tensile test exhibited that the specimen rolled to the intermediate reduction (50%) performed the best strength-ductility balance (870 MPa of tensile strength and 9% of uniform elongation). The reason for the good strength-ductility balance of the specimen rolled to the intermediate reduction was discussed on the basis of the observed microstructures. q

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Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of rolling reduction on ultrafine grained structure and mechanical properties of low-carbon steel thermomechanically processed from martensite starting structure

Ueji

Tsuji

Minamino

et al. 2004

Science and Technology of Advanced Materials

109

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Effect of Niobium on the Formation of Nano/Ultrafine Grain Structure in a Low Carbon Steel by Thermomechanical Treatment

Abbasi¹,

Kermanpur²,

Najafizadeh³

2013

TMS2013 Supplemental Proceedings

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The formation of nano/ultrafine grained ferrite in low carbon steels containing different amounts of niobium was investigated using thermomechanical treatment which consisted of annealing of 85% cold rolled martensite with different parameters. The specimens were characterized by optical and scanning electron microscopy and Vickers hardness test. A lamellar dislocation cell structure was formed during cold rolling. An increase in hardness was found during annealing with the addition of the Nb element. The mean grain size of the specimens annealed at 550 ºC for 300 s was approximately similar (ranging from 79 to 87 nm) for both chemical compositions. Increasing annealing temperature to 600 ºC or annealing time to 2.7 ks led to a severe grain growth in the steel without Nb, but no considerable changes in Nb containing steel were observed.

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Effect of Martensite on Deformation Structure and Recrystallization Behavior in Ferritic Stainless Steel

Kimura

Ushioda

Ishimaru

et al. 2016

Proceedings of the 6th International Conference on Recrystallization and Grain Growth (ReX&GG 2016)

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Ultragrain refinement of plain low carbon steel by cold-rolling and annealing of martensite

Cited by 336 publications

References 25 publications

Effect of rolling reduction on ultrafine grained structure and mechanical properties of low-carbon steel thermomechanically processed from martensite starting structure

Effect of rolling reduction on ultrafine grained structure and mechanical properties of low-carbon steel thermomechanically processed from martensite starting structure

Effect of Niobium on the Formation of Nano/Ultrafine Grain Structure in a Low Carbon Steel by Thermomechanical Treatment

Effect of Martensite on Deformation Structure and Recrystallization Behavior in Ferritic Stainless Steel

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