Influence of Nitrogen Content on the Microstructure and Precipitate of the Medium-Carbon Vanadium Microalloyed Steel

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The microstructure and precipitate of the two kinds of medium-carbon vanadium microalloyed steels whose nitrogen contents were 0.0035% and 0.012% respectively, were studied by image analysis and transmission electron microscope (TEM). The results show there are the large amount of 10~20nm dispersion distribution irregular flake VC precipitates within the ferrite, the part of clustered fibrous VC precipitates with the diameter of 4~13nm that grow toward to ferrite intracrystalline along the grain boundary with some angle in the local area, and only a very small amount of 20 ~ 50nm spherical particles V (C, N) in the low-nitrogen steel. However, in the high-nitrogen steel, the precipitates are divided into two stages: the first stage is the part of 30~80nm spherical particles V(C, N) which precipitation in austenite, the second stage is flakiness VC which precipitation in ferrite during the following γ → α phase transformation and cooling process. Compared with the low-nitrogen steel, the number of precipitates in decreased significantly and the size increased obviously in the high-nitrogen steel. The substantial increase of nitrogen content leads to the rapid increase of driving force that V (C, N) precipitation in austenite. A lot of V (C, N) that precipitation before phase transformation results in the significant increase of ferrite nucleation rate, which leads to the microstructure of high-nitrogen steel fined obviously.

Info:

Periodical:

Advanced Materials Research (Volumes 311-313)

Edited by:

Zhongning Guo

Pages:

817-821

DOI:

10.4028/www.scientific.net/AMR.311-313.817

Citation:

Y. Guan et al., "Influence of Nitrogen Content on the Microstructure and Precipitate of the Medium-Carbon Vanadium Microalloyed Steel", Advanced Materials Research, Vols. 311-313, pp. 817-821, 2011

Online since:

August 2011

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Price:

$38.00

[1] Charleux M, Poole W J, Militizer M , Deschamps A. Metall M ater Trans, 2001. 32A: 1635.

[2] Sun J, Boyd J D. Int J Pressure Vessels Piping, 2000; 77: 369.

[3] Weng Yuqing. Ultra-fine Grained Steel-Theories and Technologies of Structure Fined[M]. Beijing: Metallurgical Industry Press, 2003, 118-127.

[4] zajac S. Mater Sci Forum, 2005; 500: 75.

[5] Lagneborg R, Zajac S. Metall Mater Trans, 2001; 32A: 39.

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