Engine Titanium Consortium - Center for Nondestructive Evaluation ...

Peak> Range of Ave. Range of Peak
GE: 0.81% 2.03% 0.2% - 1.9% 0.5% - 6.1%
PW: 0.83% 2.31% 0.4% - 1.8% 0.7% - 5.5%
HW: 0.88% 2.36% 0.4% - 2.5% 0.6% - 6.9%
(#1 FBH in Ti 6-4 = 100%)
Table 1. Comparison of average and maximum gated-peak noise voltages seen in the suites of
coupons from the GE, P&W, and HW forgings. The first two columns list the average and
maximum values for a given forging, averaged over all coupons, inspection directions, and analysis
quadrants. The last two columns list the ranges of measured values for average and peak noise in
each forging.
Table 2. Comparison of UT properties for the high-noise coupons from the Pratt&Whitney, General
Electric, and Honeywell Ti 6-4 forgings.
Noise Curvature Blocks
PW GE HW
velocity (cm/usec): 0.622 0.618 0.621
density (gm/cc): 4.43 4.43 4.43
attenuation power law * : 6.83E-4*freq^1.79 4.31E-5*freq^2.26 8.20E-4*freq^1.34
attenuation at 10 MHz: 0.93 dB/inch 0.17 dB/inch 0.40 dB/inch
FOM power law * : 1.61E-3*freq^1.25 2.95E-3*freq^0.896 4.15E-3*freq^1.078
Meas. FOM at 10 MHz: 0.027 0.021 0.047
* For power laws, units are N/cm for attenuation, and
cm^-0.5 for FOM, with the frequency input in MHz.
Six “noise curvature blocks” were made to investigate the manner in which surface curvature
influences inspection sensitivity in forgings. A principal use of the blocks will be to test models that
predict the characteristics of backscattered grain seen during forging inspections. The six blocks,
each measuring approximately 1.6” x 5.9” x 2” (axial x radial x hoop) were fabricated by
Pratt&Whitney from one of their Ti 6-4 forgings. The location of each block within the forging
cross-section is shown in Figure 8a. For five of the blocks, the upper surface in Figure 10a is
curved, while the sixth block has a flat upper surface. Although each block was cut from the same
position in the radial/axial plane of the forging, the blocks, of necessity, had different angular
positions, as shown in Figure 8b. Since microstructural variations in the hoop direction of a forging
are often minor, it was hoped that this construction method would produce six blocks with nearly
identical microstructures.
Quarterly Report – January 1, 2002 –March 31, 2002
print date/time: 6/6/2002 - 8:39 AM – Page 42