Paper Titles
Strain-Induced Precipitation of Nb(CN) during Deformation of Undercooled Austenite in Nb-Microalloyed HSLA Steels
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Distribution of Mo at Grain Boundary of 1300MPa CrMo Steel
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The Mechanism of Intragranular Ferrite Nucleation on Inclusion in Steel
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Subsurface Microstructure Evolution of Hadfield Steel under High Impact Energy
p.117
Evolution of Microstructures in a Low Carbon Bainitic Steel during Reheating
p.121
Dislocation-Precipitate Interaction and Its Effect on Thermostability of Bainite in a Nb-Bearing Steel
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The Aging Behavior for Low Carbon Bainitic Steel Bearing Cu-Nb
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Surface Nanocrystallization of Low Carbon Steel Induced by Circulation Rolling Plastic Deformation
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Microstructures and Microhardness of SNCed Medium Carbon Low Alloy Steels
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Evolution of Microstructures in a Low Carbon Bainitic Steel during Reheating

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Abstract:

Cooled in water after isothermal relaxation of deformed austenite for different time, a Nb-bearing microalloyed steel always exhibited synthetic microstructures of bainitic ferrite, granular bainite and acicular ferrite. When these samples were reheated to and held at 650°C or 700 °C, the non-equilibrious microstructures tended to evolve into equilibrious ones, accompanied by obvious change of hardness. The rate of microstructures evolution was closely related to relaxation time of deformed austenite. The sample relaxed for 60s displayed the highest thermal stability, while microstructure evolution was quickest in the sample relaxed for 1000s even though it was softest before reheating. By hardness measurement, it was found that softening was not only process occurring during reheating, in which hardness fluctuated with time. There were two peaks in hardness-time curve of each sample having undergone relaxation, while single peak occurred in the curve of the sample not being relaxed. These results indicate that thermal stability of microstructures is determined by their history of formation.

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Periodical:

Materials Science Forum (Volumes 475-479)

Pages:

121-124

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.475-479.121

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Online since:

January 2005

Authors:

Hui Bin Wu, Shan Wu Yang, S.Q. Yuan, Cheng Jia Shang, Xue Min Wang, Xin Lai He

Keywords:

Bainite, Evolution, Microstructure, Reheating

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© 2005 Trans Tech Publications Ltd. All Rights Reserved

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References

[1] Hurley P J, Kelly G L, Hodgson P D. Mater Sci Tech, 2000; 16: 1273.

Google Scholar

[2] Wang X M, He X L, Yang S W, Shang C J, Wu H B. ISIJ international, 2002; 42: 1553.

Google Scholar

[3] Jong- Kyo CHOI, Dong Han SEO, Jae-Sang LEE et al. ISIJ International, 2003, 43: 746.

Google Scholar

[4] Wang X M, Shang C J, Yang S W, He X L, Wu H B. J Unv Sci Tech Beijing, 2002; 19: 193.

Google Scholar

[5] Park K T, Kim Y S, Lee J G, Shin D H. 2000; A293: 165.

Google Scholar

[6] Shin D H, Kim B C, Park K T, Choo W Y, Acta Mater, 2000; 48: 3245.

Google Scholar

[7] Yang S W, Shang C J, He X L, Wang X M, Yuan Y. J Unv Sci Tech Beijing, 2001; 8: 119.

Google Scholar

[8] Abe F. Mater. Sci. Eng, 1997; A234-236: 1045.

Google Scholar

[9] Hong S G, Lee W B, Park C G. Nuclear Mater, 2001; 288: 202.

Google Scholar

[10] Sakasegawa H, Hirose T, Kohyama A, Katoh Y, Harada T, Asakura K. Fusion Engineering and Design, 2002; 61-62: 671.

DOI: 10.1016/s0920-3796(02)00290-9

Google Scholar