SYMPOSIA PAPER Published: 01 January 1974

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


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.

Author Information

Koppenaal, TJ
Philco-Ford Corporation, Newport Beach, Calif.
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Developed by Committee: E28
Pages: 92–117
DOI: 10.1520/STP32187S
ISBN-EB: 978-0-8031-4647-1
ISBN-13: 978-0-8031-0738-0