Accession Number:

AD0882120

Title:

Development of Fracture Toughness Properties of D6-AC Steel for F-111 Applications.

Descriptive Note:

Final rept. Apr-Oct 70,

Corporate Author:

BOEING AEROSPACE CO SEATTLE WA

Personal Author(s):

Report Date:

1971-01-01

Pagination or Media Count:

98.0

Abstract:

Surface flawed, D6-AC steel, specimens were tested to spot check and supplement fracture and flaw growth rate data obtained from other type specimens used in life prediction of F-111 aircraft structure. Sustained load tests were run in distilled water at 35F, 75F, and 175F and in dry air at room temperature. Cyclic loading was conducted over a range of temperatures from -40F to 175F in dry air, distilled water, JP-4 fuel, 3-12 NaCl solution, and 50 relative humidity air. Other parameters considered were flaw shape a2c ratio, stress level, stress ratio, and frequency. Fracture toughness values obtained from surface flawed specimens were higher than those obtained from compact tension specimens. Relative effects of environment and testing parameters on flaw growth rates compared favorably in most cases for surface flawed specimens and compact tension specimens. Less conservative surface flaw models than semi-circular are possible for prediction of safe life. Author

Subject Categories:

  • Attack and Fighter Aircraft
  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE