STP415: Fatigue-Crack Propagation in Some Ultrahigh-Strength Steels

    Wei, R. P.
    personal member of ASTM, United States Steel Corp.Lehigh UniversityAluminum Company of AmericaCornell University, MonroevilleBethlehemNew KensingtonIthaca, Pa.Pa.Pa.N. Y.

    Talda, P. M.
    personal member of ASTM, United States Steel Corp.Lehigh UniversityAluminum Company of AmericaCornell University, MonroevilleBethlehemNew KensingtonIthaca, Pa.Pa.Pa.N. Y.

    Li, Che-Yu
    personal member of ASTM, United States Steel Corp.Lehigh UniversityAluminum Company of AmericaCornell University, MonroevilleBethlehemNew KensingtonIthaca, Pa.Pa.Pa.N. Y.

    Pages: 26    Published: Jan 1967


    Abstract

    Fatigue-crack propagation studies were carried out on some ultrahigh-strength steels in controlled environments using the fracture-mechanics approach. The steels investigated include a medium-carbon low-alloy ultrahigh-strength steel tempered to two strength and toughness levels, a 250-grade 18Ni maraging steel, and a 300-grade 18Ni steel. The results indicate that, in the inert environment, the rates of fatigue-crack propagation in these steels are about the same and show no obvious correlation with other mechanical properties of the steels. The sensitivity of the rates of fatigue-crack propagation to the presence of moisture in the test environment shows rough correlation with plane-strain fracture toughness for steels of similar composition. The role of water vapor in promoting fatigue-crack propagation is considered. The results are also discussed in terms of existing theories and metallographic observations.

    Keywords:

    fatigue (materials), crack propagation steels, fracture mechanics, maraging steels, nickel steels, water vapor, environmental effects


    Paper ID: STP47239S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP47239S


    CrossRef ASTM International is a member of CrossRef.