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A model for precipitation kinetics in vanadium microalloyed steel

  • Fang Fang
  • Qi-long Yong
  • Cai-fu Yang
  • Hang Su
Article

Abstract

Small dispersoid particles inhibit recrystallization which is critical in controlling the grain structure of many high strength low alloy steels. A general kinetic model has been developed to predict precipitation of V(C, N) in vanadium microalloyed steels with a series of carbon and nitrogen contents. The solubility product and driving force of carbonitrides precipitated in austenite as well as the interfacial energy and other parameters can be evaluated to predict Nucleation rates-Temperature (NrT) and Precipitation-Time-Temperature (PTT) diagram. By using stress relaxation tests and fitting with Avrami equation, it is possible to draw PTT diagrams. The predictions of the model coincide with results of experimental investigation on V(C, N) precipitation in austenite. The nose temperature is around 850 °C obtained by experiment which is different from the prediction of the model and the difference is 30 °C, and nitrogen has more effect on the shape of “C” curve of PTT diagram than carbon that makes “C” curve move leftward significantly.

Key words

kinetic calculation model PTT curve stress relaxation nitrogen 

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References

  1. [1]
    Inoue K, Ishikawa N, Ohnuma I, et al. Calculation of Phase Equilibria Between Austenite and (Nb, Ti, V)(C, N) in Microalloyed Steels [J]. ISIJ International, 2001, 41(2): 176.CrossRefGoogle Scholar
  2. [2]
    YONG Qi-long. Secondary Phases in Steels [M]. Beijing: Metallurgical Industry Press, 2006(in Chinese).Google Scholar
  3. [3]
    Khan I N, Starink M J, Yan J L. A Model for Precipitation Kinetics and Strengthening in Ai-Cu-Mg Alloys [J]. Materials and Engineering, 2008, 472A(1/2): 66.CrossRefGoogle Scholar
  4. [4]
    Robson J D. A New Model for Prediction of Dispersoid Precipitation in Aluminium Alloys Containing Zirconium and Scandium [J]. Acta Materialia, 2004, 52(6): 1409.CrossRefGoogle Scholar
  5. [5]
    Robson J D. Modelling the Overlap of Nucleation, Growth and Coarsening During Precipitation [J]. Acta Materialia, 2004, 52 (15): 4669.CrossRefGoogle Scholar
  6. [6]
    Wagner R, Kampmann R. Phase Transformations in Materials [C] //Cahn R, Haasen P, Kramer E J. Material Science and Technology; A Comprehensive Treatment Vol. 5. Weinheim: Wiley-VCH, 1991: 213.Google Scholar
  7. [7]
    YUAN Shao-qiang. Influence of Relaxation-Precipitation-Controlling Transformation Process on the Precipitation in Microalloyed Steel [D]. Beijing: University of Science and Technology Beijing, 2004 (in Chinese).Google Scholar
  8. [8]
    Medina S F, Quispe A, Gómez M. Model for Static Recrystallisation Critical Temperature in Microalloyed Steels [J]. Materials Science and Technology, 2001, 17(5): 536.CrossRefGoogle Scholar
  9. [9]
    Quispe A, Medina S F, Gómez M, et al. Influence of Austenite Grain Size on Recrystallisation-Precipitation Interaction in a V-Microalloyed Steel [J]. Materials Science and Engineering, 2007, 447A(1/2): 11.CrossRefGoogle Scholar

Copyright information

© China Iron and Steel Research Institute Group 2010

Authors and Affiliations

  1. 1.Structure Material InstituteCentral Iron and Steel Research InstituteBeijingChina

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