Microstructural Evolution of a 12Cr-2W-Cu-V-Nd Steel during Three-year Service Exposure

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Microstructural evolution of 12Cr–2W–Cu–V–Nb steel tubes (ASME SA213-T122) after one-year and three-year service exposure tests in a Japanese practical boiler has been investigated from a standpoint of the phase stability of precipitates. The test tubes consist of tempered martensite and δ-ferrite, and the main precipitates are MX-type carbonitride, M<sub>23</sub>C<sub>6</sub> carbide and Laves phase. TEM observations on thin films show that the MX has precipitated in a plate-shaped with a coherent or semi-coherent relationship with the matrix inside grains. An estimation of the lattice misfit between MX and the matrix suggests that the coherent strain has been high enough to enhance the shear stress and then strongly interact with dislocations. Another important point is that morphology and compositions of MX have been stable under the present service conditions, thereby the creep strength as well as tensile strength has kept high after long-term service exposure.<br>The long-term exposure to the present service temperature has enhanced the precipitation of Fe<sub>2</sub>(W, Mo) Laves phase inside grains, resulting in a marked reduction in the dissolved W and Mo in matrix. It is found that the kinetics of W-partitioning between matrix and Laves phase can be successfully expressed by the Johnson–Mehl–Avrami type equation and applied to estimate the actual temperatures of the exposed tubes.<br>It is concluded that the kinetics of Laves phase precipitation and morphology of MX have mainly controlled a microstructural stability in the 12Cr–2W–Cu–V–Nb steel, and also give helpful suggestion to increase the creep resistance during the long-term service exposure.

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  • ISIJ international

    ISIJ international 40(11), 1156-1163, 2000-11-15

    The Iron and Steel Institute of Japan

参考文献:  18件中 1-18件 を表示

  • <no title>

    MASUYAMA F.

    ISIJ Int. 34, 587, 1994

    被引用文献3件

  • <no title>

    MASUYAMA F.

    The Thermal and Nuclear power 46, 498, 1995

    被引用文献4件

  • <no title>

    SIKKA V. K.

    ASM 1st Conf Production, Fabrication, Properties and Application of Ferritic Steels for High-Temperature Applications, 1981

    被引用文献2件

  • <no title>

    ISEDA A.

    Proc.5th Int.Conf., Creep Materials 389, 1992

    被引用文献1件

  • <no title>

    IGARASHI M.

    Proc.Int.Conf.Power Engineering-'97 2, 107, 1997

    被引用文献3件

  • <no title>

    MIYATA K.

    Proc.Int.Conf.Power Engineering-'97 2, 83, 1997

    被引用文献1件

  • <no title>

    MIYATA K.

    ISIJ Int. 39, 947, 1999

    被引用文献2件

  • <no title>

    ABE F.

    Proc.8th Int.Conf.Creep and Fracture of Engineering Materials and Structures 395, 1999

    被引用文献1件

  • <no title>

    KADOYA Y.

    The 6th Liege Conf.Materials for Advanced Power Engineering 368, 1998

    被引用文献2件

  • <no title>

    MASUYAMA F.

    Proc.Int.Conf.Power Engineering-'97 2, 95, 1997

    被引用文献1件

  • <no title>

    ISEDA A.

    Tetsu-to-Hagane 76, 2190, 1990

    被引用文献2件

  • <no title>

    CAHN J. W.

    Acta Metall. 4, 449, 1956

    被引用文献15件

  • <no title>

    HOGLUND Lars

    Foundation of Computational Thermodymnamics 1, 1997

    被引用文献1件

  • <no title>

    PICKERING F. B.

    Physical Metallurgy and THe Design of Steels 12, 1978

    被引用文献3件

  • <no title>

    FRIEDEL J.

    Electron Microscopy and Strength of Crystals 605, 1962

    被引用文献2件

  • <no title>

    FOREMAN A. J. E.

    Philos, Mag. 14, 911, 1966

    被引用文献3件

  • <no title>

    ARDELL A. J.

    Metall.Trans.A 16, 2131, 1985

    被引用文献2件

  • <no title>

    PEARSON W. B.

    A Handbook of Lattice Spacing and Structure of Metals and Alloys, 1956

    被引用文献1件

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