STP857: Variable-Amplitude Fatigue Crack Initiation and Growth of Five Carbon or Low-Alloy Cast Steels at Room and Low Climatic Temperatures

    Stephens, RI
    professorresearch assistants or former research assistants, The University of IowaMaterials Engineering Division, The University of Iowa, Iowa City, IA

    Fatemi, A
    professorresearch assistants or former research assistants, The University of IowaMaterials Engineering Division, The University of Iowa, Iowa City, IA

    Lee, HW
    professorresearch assistants or former research assistants, The University of IowaMaterials Engineering Division, The University of Iowa, Iowa City, IA

    Lee, SG
    professorresearch assistants or former research assistants, The University of IowaMaterials Engineering Division, The University of Iowa, Iowa City, IA

    Vacas-Oleas, C
    professorresearch assistants or former research assistants, The University of IowaMaterials Engineering Division, The University of Iowa, Iowa City, IA

    Wang, CM
    professorresearch assistants or former research assistants, The University of IowaMaterials Engineering Division, The University of Iowa, Iowa City, IA

    Pages: 20    Published: Jan 1985


    Abstract

    Five common cast steels were subjected to SAE transmission history at room temperature and three low climatic temperatures using an as-drilled keyhole notched compact specimen. The three low temperatures were −34, −45, and −60°C. These temperatures were both above and below nil ductility transition temperatures. Three fatigue criteria were specifically monitored: crack initiation defined by the first visible surface crack Δa equal to 0.25 mm, Δa equal to 2.5 mm, and final fracture. All low-temperature total fatigue lives were equal to or better than at room temperature for four of the five cast steels. All steels exhibited crack initiation lives at low temperatures equal to or better than at room temperature. Fatigue crack growth life tended to increase as the temperature was lowered, and then this trend reversed. Scanning electron fractographic analysis showed all ductile type fatigue crack growth mechanisms above or below the nil ductility transition temperature.

    Keywords:

    fatigue (materials), cast steel, low temperature, crack initiation, notches, crack growth, spectrum loading, fractography, mechanisms, striations, nil ductility transition


    Paper ID: STP32762S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP32762S


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