Engine Titanium Consortium - Center for Nondestructive Evaluation ...

Noise C-scans through the “Flat Surfaces” of the Six Specimens
10 MHz, 0.375”D, focal depth in water = 2.65”, Amp=7, Damping=1, Pulse Width = 20ns
Waterpath = 1.0in, Focus ≈ 0.5” deep, Gain = 57.0dB, Gate delay = 0.3in, Gate Range = 0.4in
OD
Thicker region
Thinner region
ID
22.4%
10.0” Radius Convex Block
28.4%
18.8%
4.0” Radius Convex Block
27.2%
17.1%
Flat Reference Block
14.1%
22.9%
0.75” Radius Concave Block
32.8%
23.3%
2.0” Radius Concave Block
32.3%
19.9%
8.0” Radius Concave Block
30.5%
Figure 9. Preliminary C-scans showing gated-peak grain noise levels measured through the flat
surfaces of the six noise curvature blocks. Average noise levels as a percentage of full screen
height are listed.
Noise Measurements thru Flat Entry Surfaces
2.4" water path; 57 dB
Noise Measurements thru Flat Entry Surfaces
2.4" water path; 57 dB
RMS Grain Noise (% of FSH) .
12
Flat, FBHs in back
Flat, FBHs in front
0.75 cv 2.0 cv
10
8.0 cv 4.0 cx
10.0 cx Theory
8
Model assumes: FOM = 1.1* (5.6E-4*freq^1.25)
Atten = 5.7E-4*freq^1.8
6
4
2
Exp. values corrected for electronic
noise and Ref signal differences
0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
RMS Grain Noise (% of FSH) .
12
Theory
Exp. Ave.
10
Model assumes: FOM = 1.1* (5.6E-4*freq^1.25)
Atten = 5.7E-4*freq^1.8
8
6
4
2
Exp. values correctedfor electronic
noise and Ref signal differences
0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
Metal Depth (inches)
Metal Depth (inches)
Figure 10. Comparison of measured and predicted rms grain noise levels for inspections through
the flat surfaces of the six noise curvature blocks using a 2.4” water path. Left-hand panel displays
the measured noise levels for the six blocks individually, while the right-hand panel displays their
average.
Quarterly Report – January 1, 2002 –March 31, 2002
print date/time: 6/6/2002 - 8:39 AM – Page 46