Reference Standards For Cracks.
The AF general purpose eddy current standard, NSN 6635-01-092-5129, P/N
7947479-10, SHALL be the common standard used to perform eddy current
inspections on aluminum components within the Air Force unless otherwise
specified by the cognizant weapon system engineering authority. See Figure 4-47
through Figure 4-49. Figure 4-50 is the Navy version of this standard. The Navy
Eddy Current Reference Standard Kit, Part Number NRK-3AST, consists of (1)
Aluminum, Part Number NRK-3A, 7075-T651 top & middle layer, 7075-T73
bottom layer; (1) Steel, Part Number NRK-3S, 4340 alloy all three layers and (1)
Titanium, Part Number 6AL4V alloy all three layers.
Figure 4-47. Air Force General Purpose Eddy Current Standard.