STP563: Dynamic Fracture Toughness Measurements of High-Strength Steels Using Precracked Charpy Specimens

    Koppenaal, TJ
    Supervisor, Philco-Ford Corporation, Newport Beach, Calif.

    Pages: 26    Published: Jan 1974


    The dynamic fracture toughness, KId, was measured in a number of ferrous alloys using precracked Charpy specimens and an instrumented impact machine. The alloys investigated included quenched and tempered steels (H-11, D6AC, and 4340), 18Ni maraging steels (grades 200, 250, and 300) and a high-temperature, stainless maraging steel (Pyromet X-15). Standard Charpy specimens were precracked in fatigue and tested at either 72°F (22°C) or -65°F (-54°C). Values of KId, were determined as a function of yield strength and microstructure, and correlations were established between KId and both the energy to initiate fracture, Wm/A, and the total energy of fracture, W/A. The instrumented, precracked Charpy test is shown to be a convenient method of determining relative fracture toughness; under proper conditions this test procedure can be used to determine the dynamic planestrain fracture toughness.


    impact tests, dynamic tests, toughness, fracturing, ferrous alloys, strain rate, low temperature tests, evaluation tests

    Paper ID: STP32187S

    Committee/Subcommittee: E28.07

    DOI: 10.1520/STP32187S

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