Acoustic Emission from Aqueous Stress Corrosion Cracking in Various Tempers of 4340 Steel.
Abstract
A commercially available system is employed to detect and count acoustic emissions emanating from the aqueous stress corrosion crack propagation in 4340 steel. Standard ASTM E399 compact tension specimens are prepared in four tempering temperatures: 204, 316, 427 and 538C (400, 600, 800, 1000F). Crack length is monitored with a notch opening clip gage. Comparisons show the time rate of emission events to increase with stress intensity in rough correspondence to, but much more rapidly than, the crack velocity. Tempering back tends to suppress the count rate as a warning of fast fracture instability. Some similarity is observed between the areal rate of acoustic emission and factors which influence degree and intensity of plastic flow instability in the fracture process zone. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1973
- Accession Number
- AD0764048
Entities
People
- H. H. Chaskelis
- J. M. Krafft
- W. H. Cullen
Organizations
- United States Naval Research Laboratory