Fracture propagation toughness measurements

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6434143

Wilkowski, G M

Recent data are presented that indicate differences between the fracture-initiation and -propagation toughness levels in line-pipe steels. The prediction of the temperature and toughness conditions at which the distinction between the different levels becomes important is discussed. For high-toughness quenched and tempered line-pipe steels (greater than 150 ft-lb of full-size Charpy energy), the results indicate that the pressed-notch drop-weight tear test (DWTT) transition temperature is artificially low and does not correlate with the transition temperature of fractures in pipe experiments. Predicting the fracture-propagation transition temperature accurately for these materials requires an embrittled-notch DWTT specimen, such as a precracked or brittle-weld-notch sample. The ductile-fracture-propagation toughness can be evaluated in low-toughness line-pipe steels (generally less than 50 ft-lb of Charpy energy) using either the Charpy V-notch plateau energy or the DWTT pressed-notch energy. Either provides a satisfactory empirical measure of the fracture-propagation toughness. Only the DWTT results, however, provide a direct temperature relationship with the pipe-fracture behavior.

• OSTI ID: 6434143
• Report Number(s): CONF-7910293-
• Country of Publication: United States
• Language: English

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