Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C

Roman Mouginot, Sarikka, Mikko Heikkilä, Ulla Ehrnstén, Young Suk Kim, Soo Kim Sung, Hannu Hänninen

    Research output: Contribution to conferenceConference articleScientific

    Abstract

    Alloy 690 was developed to improve the corrosion resistance of components in nuclear power systems since the 90s. Its composition is close to the Ni2Cr stoichiometry which promotes an ordering reaction upon ageing at temperatures below 550 °C with a maximum effect at 475 °C. Atomic ordering promotes lattice contraction and brittle intergranular fracture and reduces the mechanical properties. It is a concern for the structural integrity of Alloy 690 in modern pressurized water reactors (PWR), especially considering the primary water stress corrosion cracking (PWSCC) behavior. To assess the effect of ageing time, cold work and thermal treatment on the level of ordering of Alloy 690, four original conditions (solution annealed, solution annealed and cold rolled and/or heat-treated) were aged for up to 10 000 h at 475 °C. The microstructures were characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), and the ordering levels were assessed by hardness and lattice parameter measurements. All conditions showed evidence of short-range ordering. As compared to the solution annealed condition, thermal treatment decreased the level of ordering. Cold worked samples showed contradictory results with reduced hardness increase but stronger lattice contraction.
    Original languageEnglish
    Pages17
    Publication statusPublished - 2015
    Event17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015 - Ottawa, Canada
    Duration: 9 Aug 201512 Aug 2015

    Conference

    Conference17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015
    Abbreviated titleENVDEG 2015
    CountryCanada
    CityOttawa
    Period9/08/1512/08/15

    Fingerprint

    heat treatment
    contraction
    hardness
    pressurized water reactors
    stress corrosion cracking
    corrosion resistance
    integrity
    stoichiometry
    lattice parameters
    mechanical properties
    heat
    microstructure
    scanning electron microscopy
    diffraction
    water
    electrons
    temperature

    Keywords

    • alloy 690
    • thermal ageing
    • short-range ordering
    • Ni2Cr
    • cold work
    • thermal treatment

    Cite this

    Mouginot, R., Sarikka, Heikkilä, M., Ehrnstén, U., Kim, Y. S., Sung, S. K., & Hänninen, H. (2015). Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C. 17. Paper presented at 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015, Ottawa, Canada.
    Mouginot, Roman ; Sarikka ; Heikkilä, Mikko ; Ehrnstén, Ulla ; Kim, Young Suk ; Sung, Soo Kim ; Hänninen, Hannu. / Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C. Paper presented at 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015, Ottawa, Canada.
    @conference{a5e3ce0270c6425189198077978f30e2,
    title = "Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C",
    abstract = "Alloy 690 was developed to improve the corrosion resistance of components in nuclear power systems since the 90s. Its composition is close to the Ni2Cr stoichiometry which promotes an ordering reaction upon ageing at temperatures below 550 °C with a maximum effect at 475 °C. Atomic ordering promotes lattice contraction and brittle intergranular fracture and reduces the mechanical properties. It is a concern for the structural integrity of Alloy 690 in modern pressurized water reactors (PWR), especially considering the primary water stress corrosion cracking (PWSCC) behavior. To assess the effect of ageing time, cold work and thermal treatment on the level of ordering of Alloy 690, four original conditions (solution annealed, solution annealed and cold rolled and/or heat-treated) were aged for up to 10 000 h at 475 °C. The microstructures were characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), and the ordering levels were assessed by hardness and lattice parameter measurements. All conditions showed evidence of short-range ordering. As compared to the solution annealed condition, thermal treatment decreased the level of ordering. Cold worked samples showed contradictory results with reduced hardness increase but stronger lattice contraction.",
    keywords = "alloy 690, thermal ageing, short-range ordering, Ni2Cr, cold work, thermal treatment",
    author = "Roman Mouginot and Sarikka and Mikko Heikkil{\"a} and Ulla Ehrnst{\'e}n and Kim, {Young Suk} and Sung, {Soo Kim} and Hannu H{\"a}nninen",
    note = "Project code: 102621 ; 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015, ENVDEG 2015 ; Conference date: 09-08-2015 Through 12-08-2015",
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    Mouginot, R, Sarikka, Heikkilä, M, Ehrnstén, U, Kim, YS, Sung, SK & Hänninen, H 2015, 'Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C', Paper presented at 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015, Ottawa, Canada, 9/08/15 - 12/08/15 pp. 17.

    Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C. / Mouginot, Roman; Sarikka; Heikkilä, Mikko; Ehrnstén, Ulla; Kim, Young Suk; Sung, Soo Kim; Hänninen, Hannu.

    2015. 17 Paper presented at 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015, Ottawa, Canada.

    Research output: Contribution to conferenceConference articleScientific

    TY - CONF

    T1 - Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C

    AU - Mouginot, Roman

    AU - Sarikka, null

    AU - Heikkilä, Mikko

    AU - Ehrnstén, Ulla

    AU - Kim, Young Suk

    AU - Sung, Soo Kim

    AU - Hänninen, Hannu

    N1 - Project code: 102621

    PY - 2015

    Y1 - 2015

    N2 - Alloy 690 was developed to improve the corrosion resistance of components in nuclear power systems since the 90s. Its composition is close to the Ni2Cr stoichiometry which promotes an ordering reaction upon ageing at temperatures below 550 °C with a maximum effect at 475 °C. Atomic ordering promotes lattice contraction and brittle intergranular fracture and reduces the mechanical properties. It is a concern for the structural integrity of Alloy 690 in modern pressurized water reactors (PWR), especially considering the primary water stress corrosion cracking (PWSCC) behavior. To assess the effect of ageing time, cold work and thermal treatment on the level of ordering of Alloy 690, four original conditions (solution annealed, solution annealed and cold rolled and/or heat-treated) were aged for up to 10 000 h at 475 °C. The microstructures were characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), and the ordering levels were assessed by hardness and lattice parameter measurements. All conditions showed evidence of short-range ordering. As compared to the solution annealed condition, thermal treatment decreased the level of ordering. Cold worked samples showed contradictory results with reduced hardness increase but stronger lattice contraction.

    AB - Alloy 690 was developed to improve the corrosion resistance of components in nuclear power systems since the 90s. Its composition is close to the Ni2Cr stoichiometry which promotes an ordering reaction upon ageing at temperatures below 550 °C with a maximum effect at 475 °C. Atomic ordering promotes lattice contraction and brittle intergranular fracture and reduces the mechanical properties. It is a concern for the structural integrity of Alloy 690 in modern pressurized water reactors (PWR), especially considering the primary water stress corrosion cracking (PWSCC) behavior. To assess the effect of ageing time, cold work and thermal treatment on the level of ordering of Alloy 690, four original conditions (solution annealed, solution annealed and cold rolled and/or heat-treated) were aged for up to 10 000 h at 475 °C. The microstructures were characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), and the ordering levels were assessed by hardness and lattice parameter measurements. All conditions showed evidence of short-range ordering. As compared to the solution annealed condition, thermal treatment decreased the level of ordering. Cold worked samples showed contradictory results with reduced hardness increase but stronger lattice contraction.

    KW - alloy 690

    KW - thermal ageing

    KW - short-range ordering

    KW - Ni2Cr

    KW - cold work

    KW - thermal treatment

    M3 - Conference article

    SP - 17

    ER -

    Mouginot R, Sarikka, Heikkilä M, Ehrnstén U, Kim YS, Sung SK et al. Effect of heat treatment and cold work on the ordening of alloy 690 at 475 °C. 2015. Paper presented at 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ENVDEG 2015, Ottawa, Canada.