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Nakajima, Keiji
Publications (10 of 58) Show all publications
Wang, W., Zhang, H., Nakajima, K., Lei, H., Tang, G., Wang, X., . . . Jiang, M. (2021). Prediction of Final Solidification Position in Continuous Casting Bearing Steel Billets by Slice Moving Method Combined with Kobayashi Approximation and Considering MnS and Fe3P Precipitation. ISIJ International, 61(11), 2703-2714
Open this publication in new window or tab >>Prediction of Final Solidification Position in Continuous Casting Bearing Steel Billets by Slice Moving Method Combined with Kobayashi Approximation and Considering MnS and Fe3P Precipitation
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2021 (English)In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 61, no 11, p. 2703-2714Article in journal (Refereed) Published
Abstract [en]

Control of MnS and Fe3P precipitate are of vital importance for the quality of the bearing steels. The precipitation behavior is not only related to shortening the bearing steel's fatigue life, but also to another serious engineering problem i.e. changing the billet final solidification position. In order to distinguish the different precipitate behavior on the influencing of the final solidification position, a slice moving method combined with Kobayashi approximation and the MnS and Fe3P precipitation is developed. The continuous casting billet of seve-component bearing steel, i.e. Fe-C-Cr-Mn-Si-P-S system, is considered as the raw material. Upon the present chemical composition of 0.004 to 0.007 mass% S and 0.011 to 0.012 mass%P in 100Cr6 (DIN -Norm) and RAD1 (GB-Norm) alloy, the MnS but not Fe3P precipitate covers the billet cross section. The onset of Fe3P precipitation is at 0.019 mass% P in 100Cr6 alloy and 0.021 mass% P in RAD1 alloy. The distribution of the maximum amount of MnS and Fe3P precipitate is similar, i.e. concentrating at the billet center. The increase of P composition, besides accelerating the precipitation of MnS and Fe3P, elongates the liquid core length. In contrast, the increase of S composition and the precipitation of MnS greatly shortens the liquid core length. Thus it is vital to control composition of S, P solute to a low level in bearing steels in order to stabilize the final solidification position.

Place, publisher, year, edition, pages
Iron and Steel Institute of Japan, 2021
Keywords
continuous casting bearing steel billet, liquid core length, slice moving method, Kobayashi microsegregation approximation, MnS precipitation, Fe3P precipitation
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-306810 (URN)10.2355/isijinternational.ISIJINT-2021-205 (DOI)000729899000003 ()2-s2.0-85119625827 (Scopus ID)
Note

QC 20220110

Available from: 2022-01-10 Created: 2022-01-10 Last updated: 2022-10-12Bibliographically approved
Zhang, H. W., Zhang, S., Wang, Y. C., Hao, Y. Z., Miao, M., Nakajima, K., . . . He, J. C. (2020). Cellular automaton modelling of M7C3 carbide growth during solidification of Fe-C-Cr alloy. In: International conference on modelling of casting, welding and advanced solidification processes (MCWASP XV): . Paper presented at 15th International Conference on Modelling of Casting, Welding and Advanced Solidification Processes (MCWASP), JUN 22-23, 2020, Jonkoping, SWEDEN. IOP Publishing, Article ID 012046.
Open this publication in new window or tab >>Cellular automaton modelling of M7C3 carbide growth during solidification of Fe-C-Cr alloy
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2020 (English)In: International conference on modelling of casting, welding and advanced solidification processes (MCWASP XV), IOP Publishing , 2020, article id 012046Conference paper, Published paper (Refereed)
Abstract [en]

A microscopic cellular automaton combined with macroscopic heat and solute transport was developed to simulate the mutual growth and evolution of austenite and M7C3 carbide grains during Fe-C-Cr ternary alloy solidification process. The diffusion of solute C and Cr are contributed together to the constitutional undercooling, together with curvature undercooling, for obtaining the grain growth rate of austenite and M7C3 carbide. Results show that, the absorption of solute C and Cr by M7C3 grain and rejection by austenite grain promote the two grains' cooperative growth. Once they approach to each other, the austenite grain quickly overgrows towards the M7C3 grain till finally envelops it. The simulated solidification morphology of the Fe-4wt%C-17wt%Cr alloy, predicted averaged grain size of M7C3 carbides and C and Cr concentration in austenite grains agree with the experimental measurements and solidification path prediction. The predicted average liquid concentration curve fits with the LR, GS and PE prediction at the initial M7C3 precipitation regime and after austenite grains fully enveloping towards the M7C3 grains, returns to overlap the LR, GS and PE prediction curves.

Place, publisher, year, edition, pages
IOP Publishing, 2020
Series
IOP Conference Series-Materials Science and Engineering, ISSN 1757-8981 ; 861
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-288653 (URN)10.1088/1757-899X/861/1/012046 (DOI)000594112500046 ()2-s2.0-85087020016 (Scopus ID)
Conference
15th International Conference on Modelling of Casting, Welding and Advanced Solidification Processes (MCWASP), JUN 22-23, 2020, Jonkoping, SWEDEN
Note

QC 20210112

Available from: 2021-01-12 Created: 2021-01-12 Last updated: 2022-11-30Bibliographically approved
Xuan, C., Nakajima, K., Shibata, H. & Jönsson, P. G. (2020). Wetting and spreading behavior of liquid iron on single crystal TiO2 substrate. Materials letters (General ed.), 258, Article ID 126778.
Open this publication in new window or tab >>Wetting and spreading behavior of liquid iron on single crystal TiO2 substrate
2020 (English)In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 258, article id 126778Article in journal (Refereed) Published
Abstract [en]

This work reported the wetting and spreading behavior of pure iron droplet on single crystal TiO2 substrate. During the heating process, a "FeO center dot TiOx separated liquid phase" appeared at the temperature below the melting point of the pure iron, and completely covered the lower half of the iron droplet. The observed high-wetting behavior of the droplet is due to the spreading of the "separated liquid phase" rather than the iron droplet flow. According to both thermodynamic considerations and experimental measurements, the "separated liquid phase" is formed through the chemical interactions among the iron specimen, oxygen gas in the Ar atmosphere and TiO2 substrate.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Interfacial phenomenon, Reactive wetting, Partial pressure oxygen, TiO2
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-266203 (URN)10.1016/j.matlet.2019.126778 (DOI)000500934600058 ()2-s2.0-85073018000 (Scopus ID)
Note

QC 20200113

Available from: 2020-01-13 Created: 2020-01-13 Last updated: 2022-10-12Bibliographically approved
Nakajima, K., Mu, W. & Jönsson, P. (2019). Assessment of a Simplified Correlation Between Wettability Measurement and Dispersion/Coagulation Potency of Oxide Particles in Ferrous Alloy Melt. Metallurgical and materials transactions. B, process metallurgy and materials processing science, 50(5), 2229-2237
Open this publication in new window or tab >>Assessment of a Simplified Correlation Between Wettability Measurement and Dispersion/Coagulation Potency of Oxide Particles in Ferrous Alloy Melt
2019 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, no 5, p. 2229-2237Article in journal (Refereed) Published
Abstract [en]

This article seeks to demonstrate a direct and simplified correlation between the measurement of the wettability and the agglomeration potency of the inclusion particles in liquid ferrous alloy. The established methodology has been validated by the agreement between the calculated coagulation coefficient of Al2O3 particles and the experimental data in the open literature. Subsequently, the coagulation coefficient of Al2O3, MgO, and Ti2O3 particles in ferrous alloy melts was evaluated quantitatively by the proposed method using the actual experimental data of contact angle and surface tension. Meanwhile, the effect of the matrix composition has been investigated by comparing the Hamaker constant and coagulation coefficient between Ti2O3/pure iron and Ti2O3/low-carbon steel systems. It is noted that the change of coagulation coefficient associated with the contact angle is caused by the formation of a new phase at the oxide/metal interface at the high temperature. The present work aims to provide a deep understanding of the connection between inclusion motion behavior in the liquid alloy and the high temperature interfacial phenomenon.

Place, publisher, year, edition, pages
SPRINGER, 2019
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-261293 (URN)10.1007/s11663-019-01624-x (DOI)000486025000014 ()2-s2.0-85068126410 (Scopus ID)
Note

QC 20191008

Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2022-10-12Bibliographically approved
Zhang, H., Nakajima, K., Su, M., Gao, S., Lei, H., Wang, Q. & He, J. (2019). Prediction of Carbide Precipitation Using A Combined Partial Equilibrium - Para-Equilibrium - Lever Rule Approximation in Automobile Gear Materials. In: IOP Conference Series: Materials Science and Engineering. Paper presented at Joint 5th International Conference on Advances in Solidification Processes, ICASP 2019 and 5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining, CSSCR 2019; The Pitter Event Center, Salzburg; Austria; 17 June 2019 through 21 June 2019. Institute of Physics Publishing (IOPP) (1)
Open this publication in new window or tab >>Prediction of Carbide Precipitation Using A Combined Partial Equilibrium - Para-Equilibrium - Lever Rule Approximation in Automobile Gear Materials
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2019 (English)In: IOP Conference Series: Materials Science and Engineering, Institute of Physics Publishing (IOPP), 2019, no 1Conference paper, Published paper (Refereed)
Abstract [en]

The carbide precipitation nature of an automobile gear material, i.e. Fe-C-Mn-Si-Cr-Mo alloy, during carburization and element addition process are investigated through PE+PA+LR prediction. Results show that, carburization process greatly increases the amount of cementite as well as the hardness index at the surface part. Besides, the addition of Ti and V helps to formation of TiC and (V, Mo)C carbides but suppress the precipitation of cementite, which contributes equivalent hardness at surface and lighter weight to the alloy.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2019
Series
IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981 ; 529
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-262623 (URN)10.1088/1757-899X/529/1/012009 (DOI)000561759900009 ()2-s2.0-85067846102 (Scopus ID)
Conference
Joint 5th International Conference on Advances in Solidification Processes, ICASP 2019 and 5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining, CSSCR 2019; The Pitter Event Center, Salzburg; Austria; 17 June 2019 through 21 June 2019
Note

QC 20191021

Available from: 2019-10-21 Created: 2019-10-21 Last updated: 2022-10-12Bibliographically approved
Mu, W., Hedström, P., Shibata, H., Jönsson, P. G. & Nakajima, K. (2018). High-Temperature Confocal Laser Scanning Microscopy Studies of Ferrite Formation in Inclusion-Engineered Steels: A Review. JOM: The Member Journal of TMS, 70(10), 2283-2295
Open this publication in new window or tab >>High-Temperature Confocal Laser Scanning Microscopy Studies of Ferrite Formation in Inclusion-Engineered Steels: A Review
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2018 (English)In: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 70, no 10, p. 2283-2295Article, review/survey (Refereed) Published
Abstract [en]

The concepts of oxide metallurgy and inclusion engineering can be utilized to improve the properties of low-alloy steels. These concepts aim at controlling the formation of intragranular ferrite (IGF), often a desirable microstructure providing good mechanical properties without the need for expensive alloying elements. IGF formation is stimulated to occur at non-metallic inclusions and form an arrangement of fine, interlocking ferrite grains. A method that has contributed significantly to investigations in this field lately is high-temperature confocal laser scanning microscopy (HT-CLSM). HT-CLSM is suited for in situ studies of inclusion behavior in liquid steel and phase transformations in solid-state steel, where in particular, displacive phase transformations can be studied, since they provide sufficient topographic contrast. The purpose of the present report is to provide a brief review of the state of the art of HT-CLSM and its application for in situ observations of ferrite formation in inclusion-engineered steels. The scientific literature in this field is surveyed and supplemented by new work to reveal the capability of HT-CLSM as well as to discuss the effect of factors such as cooling rate and parent grain size on IGF formation and growth kinetics. The report concludes with an outlook on the opportunities and challenges of HT-CLSM for applications in oxide metallurgy.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-235869 (URN)10.1007/s11837-018-2921-1 (DOI)000445161500052 ()2-s2.0-85046907756 (Scopus ID)
Funder
The Swedish Foundation for International Cooperation in Research and Higher Education (STINT)
Note

QC 20181012

Available from: 2018-10-12 Created: 2018-10-12 Last updated: 2024-03-15Bibliographically approved
Zhang, H., Nakajima, K., Su, M., Shibata, H., Hedström, P., Wang, W., . . . He, J. (2018). Prediction of Influences of Co, Ni, and W Elements on Carbide Precipitation Behavior in Fe–C–V–Cr–Mo Based High Speed Steels. Steel Research International, 89(10), Article ID 1800172.
Open this publication in new window or tab >>Prediction of Influences of Co, Ni, and W Elements on Carbide Precipitation Behavior in Fe–C–V–Cr–Mo Based High Speed Steels
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2018 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 89, no 10, article id 1800172Article in journal (Refereed) Published
Abstract [en]

The effects of Co, Ni together with W addition on the precipitation sequence, amount, and composition of carbides and FCC matrix in Fe–C–V–Cr–Mo based alloys are investigated with the help of Partial Equilibrium (PE) approximation and thermodynamic calculations as well as differential scanning calorimetry (DSC) and electron backscatter diffraction (EBSD) - energy dispersive spectrometer (EDS) analyses. Results show that, individually, Co and Ni elements strengthen the matrix by their great solubility in FCC matrix; W element enlarges the hardness of the alloy through benefiting the formation of M6C carbide. Mutually, the addition of Co and Ni together with W increases the precipitation temperature of the eutectic carbides, although the addition of Co and Ni itself exerts little influence on the nature (type, amount, and composition) of the carbides. These predictions combined with the experimental verifications provide potentials for the alloy design and the property control in high speed steels.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
carbide precipitation, Co, Ni, and W element addition, DSC, EBSD-EDS analysis, Fe–C–V–Cr–Mo–W–Co–Ni high speed steel, partial equilibrium approximation, Carbides, Differential scanning calorimetry, Isomers, Molybdenum alloys, Precipitation (chemical), Spectrometers, Steel metallography, Tool steel, EDS analysis, Electron back scatter diffraction, Energy dispersive spectrometers, High-speed steels, Partial equilibrium, Precipitation temperature, Thermodynamic calculations, Chromium alloys
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-236348 (URN)10.1002/srin.201800172 (DOI)000446268500007 ()2-s2.0-85050933709 (Scopus ID)
Note

QC 20181108

Available from: 2018-11-08 Created: 2018-11-08 Last updated: 2022-10-12Bibliographically approved
Nakajima, K. & Wang, Q. (2017). Preface to the Special Issue on "Cutting Edge of Computer Simulation of Solidification, Casting and Refining". High Temperature Materials and Processes, 36(4), 307-308
Open this publication in new window or tab >>Preface to the Special Issue on "Cutting Edge of Computer Simulation of Solidification, Casting and Refining"
2017 (English)In: High Temperature Materials and Processes, ISSN 0334-6455, E-ISSN 2191-0324, Vol. 36, no 4, p. 307-308Article in journal (Refereed) Published
Place, publisher, year, edition, pages
WALTER DE GRUYTER GMBH, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-206268 (URN)10.1515/htmp-2017-0010 (DOI)000398666500001 ()2-s2.0-85017003745 (Scopus ID)
Note

QC 20170512

Available from: 2017-05-12 Created: 2017-05-12 Last updated: 2022-10-12Bibliographically approved
Mu, W., Jönsson, P. & Nakajima, K. (2017). Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review. High Temperature Materials and Processes, 36(4), 309-325
Open this publication in new window or tab >>Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review
2017 (English)In: High Temperature Materials and Processes, ISSN 0334-6455, E-ISSN 2191-0324, Vol. 36, no 4, p. 309-325Article in journal (Refereed) Published
Abstract [en]

Intragranular ferrite (IGF), which nucleates from specific inclusion surfaces in low alloy steels, is the desired microstructure to improve mechanical properties of steel such as the toughness. This microstructure is especially important in the coarse grain heat affected zone (CGHAZ) of weldments. The latest review paper focusing on the role of non-metallic inclusions in the IGF formation in steels has been reported by Sarma et al. in 2009 (ISIJ int., 49(2009), 1063-1074). In recent years, large amount of papers have been presented to investigate different issues of this topic. This paper mainly highlights the frontiers of experimental and theoretical investigations on the effects of inclusion characteristics, such as the composition, size distribution and number density, on the IGF formation in low carbon low-alloyed steels, undertaken by the group of Applied Process Metallurgy, KTH Royal Institute of Technology. Related results reported in previous studies are also introduced. Also, plausible future work regarding various items of IGF formation is mentioned in each section. This work aims to give a better control of improving the steel quality during casting and in the heat affected zone (HAZ) of weldment, according to the concept of oxide metallurgy.

Place, publisher, year, edition, pages
WALTER DE GRUYTER GMBH, 2017
Keywords
inclusion, intragranular ferrite (IGF), nucleation, growth, steel, oxide metallurgy
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-206269 (URN)10.1515/htmp-2016-0175 (DOI)000398666500002 ()2-s2.0-85016999859 (Scopus ID)
Note

QC 20170512

Available from: 2017-05-12 Created: 2017-05-12 Last updated: 2022-10-12Bibliographically approved
Mu, W., Xuan, C., Shibata, H., Jönsson, P. G. & Nakajima, K. (2017). Wetting and agglomeration behavior of inclusion and intragranular ferrite formation kinetics in steel with TiO2 addition according to inclusion engineering. In: AISTech - Iron and Steel Technology Conference Proceedings: . Paper presented at AISTech 2017 Iron and Steel Technology Conference, Nashville, United States, 8 May 2017 through 11 May 2017 (pp. 3027-3036). Association for Iron and Steel Technology, AISTECH, 3
Open this publication in new window or tab >>Wetting and agglomeration behavior of inclusion and intragranular ferrite formation kinetics in steel with TiO2 addition according to inclusion engineering
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2017 (English)In: AISTech - Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, AISTECH , 2017, Vol. 3, p. 3027-3036Conference paper, Published paper (Refereed)
Abstract [en]

The comprehensive study of inclusion and microstructure characteristics in steel with TiO2 addition has been presented in this work, including wetting behavior between TiO2 and pure Fe, evaluation of inclusion agglomeration tendency, effective nuclei inclusion identification and in-situ observation of intragranular ferrite (IGF) formation. The obtained results show that TiO2 is an effective additive because it is strong wetting with liquid iron and has obvious dispersion potency. Thereafter, the effective nuclei inclusion to induce IGF formation in steel with TiO2 addition is characterized as Ti3O5 phase. The kinetic study of IGF formation using high temperature confocal laser scanning microscope shows that the fraction of IGF increases as the cooling rate increases from 3.6 to 70 °C/min and with increasing prior austenite grain size. Furthermore, it is noted that IGF morphology is refined and the onset temperatures of IGF and GBF decrease with increasing cooling rate. Finally, the onset temperature of GBF formation is higher for the steel containing a smaller grain size, however, the onset temperature of IGF formation is independent of the grain size. This work aims to give a better control of the inclusion modification as well as improving the steel quality in secondary refining and casting process, according to the concept of inclusion engineering.

Place, publisher, year, edition, pages
Association for Iron and Steel Technology, AISTECH, 2017
Keywords
Agglomeration, Confocal laser scanning microscope (CLSM), Inclusion engineering, Intragranular ferrite, TiO2, Wetting
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-212023 (URN)2-s2.0-85024497959 (Scopus ID)
Conference
AISTech 2017 Iron and Steel Technology Conference, Nashville, United States, 8 May 2017 through 11 May 2017
Note

QC 20241105

Part of ISBN 978-193511764-3

Available from: 2017-08-15 Created: 2017-08-15 Last updated: 2024-11-05Bibliographically approved
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