Depth Profiling of Residual Stress for Shot-Peened “U”-Bend Alloy-800 Tubes for the PHWR Steam Generator

    Volume 3, Issue 1

    ISSN: 2165-3992

    CODEN: MPCOAD

    Published Online: 17 January 2014

    Page Count: 14


    Kalpana Nayak, I.
    Scientific Officer, Nuclear Fuel Complex, Hyderabad,

    Ramana Rao, S. V.
    Scientific Officer, Nuclear Fuel Complex, Hyderabad,

    Kapoor, K.
    Scientific Officer, Nuclear Fuel Complex, Hyderabad,

    (Received 7 May 2013; accepted 9 December 2013)

    Abstract

    Residual tensile stresses influence the mechanical behavior in terms of fatigue and fracture resistance, stress corrosion behavior, and dimensional stability of critical components of nuclear reactors. Glass-bead shot-peened “U”-bend Alloy-800 tubes are used as steam generators in pressurized heavy water reactors (PHWRs), where stress corrosion cracking is the common cause of its premature failure. Therefore, compressive residual stresses are induced by glass-bead shot peening to overcome the tensile stresses generated more along the bend region. The variation of these compressive residual stresses as a function of depth from the surface has been estimated by successive material removal followed by stress measurement. Optimization of electropolishing parameters for removal of a fixed amount of material is carried out. Stepwise removal of material by electropolishing is proved to be better for stress analysis instead of removal “at-a-time.” Effect of shot-peening pressure is also studied as a function of stress pattern developed along the depth from the surface of the straight tube and bent tube.


    Paper ID: MPC20130017

    DOI: 10.1520/MPC20130017

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    Title Depth Profiling of Residual Stress for Shot-Peened “U”-Bend Alloy-800 Tubes for the PHWR Steam Generator
    Symposium , 0000-00-00
    Committee E07