STP518: Stress Corrosion Cracking of a High Strength Steel

    Sheinker, AA
    Lehigh University, Bethlehem, Pa.

    Wood, JD
    Lehigh University, Bethlehem, Pa.

    Pages: 23    Published: Jan 1972


    Abstract

    Stress corrosion crack growth rates (dA/dT) as a function of stress intensity factor (K) were determined over a wide range of electrode potentials for AISI 4340 steel (200-ksi yield strength level) in deaerated 3.5 percent sodium chloride solution buffered to pH 3.8. Particular emphasis was placed on conducting the stress corrosion tests under well defined electrochemical and mechanical conditions. At intermediate K levels, dA/dT was essentially independent of K, suggesting that crack growth is limited by mass transport. Crack growth is apparently dominated by localized mechanical rupturing at high K levels where dA/dT increased rapidly with increasing K. Except at a very cathodic potential, dA/dT at intermediate K levels was also independent of potential, implying that the electrochemical conditions at the tip of the stress corrosion crack are not the same as those outside the crack. The tendency for the stress corrosion cracks to branch was found to be electrochemically, as well as mechanically, controlled.

    Keywords:

    stress corrosion cracking, fracture properties, mechanical properties, high strength steels, electrochemistry, hydrogen embrittlement, failure, crack propagation, crack initiation, stress analysis, plastic deformation


    Paper ID: STP34693S

    Committee/Subcommittee: G01.06

    DOI: 10.1520/STP34693S


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