STP1000: Stress Corrosion Cracking in Alloy 400 (UNS NO4400) at Room Temperature

    Everhart, LG
    Research engineer, The Johns Hopkins University, Applied Physics Laboratory, Baltimore, MD

    Price, CE
    Professor, School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK

    Pages: 16    Published: Jan 1990


    Selective pitting studies were used to determine environments likely to cause stress corrosion cracking (SCC) in Alloy 400. Slow strain rate tests were performed on waisted specimens, with solution composition and concentration, strain rate, grain size, and prior cold work as variables. It was found that environments which caused pitting also caused SCC; examples include ammonium hydroxide, ammonium persulfate, and hydrofluoric acid in the presence of an oxidizer.

    As in the case of both hydrogen and liquid metal embrittlement of Alloy 400 and other nickel-base alloys, the SCC at low strain levels was intergranular with a transition to transgranular at higher strains. The fractography of the SCC resembled that of the other embrittling environments.


    corrosion, stress corrosion cracking, pitting, Alloy 400, intergranular cracking, transgranular cracking

    Paper ID: STP39199S

    Committee/Subcommittee: G01.06

    DOI: 10.1520/STP39199S

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