UT imaging can be used to obtain two- and three-dimensional pictures of cracks, or other types of flaws, in a pressure vessel component from an…
Category: In-Service Inspection
Time based sizing generally provides greater accuracy for determining depth, especially when the crack is relatively small with respect to the diameter of the transducer.…
Figure 700-20 illustrates how the depth of a crack is determined using amplitude based sizing techniques. The crack was detected by shear wave UT as…
The ability to determine the depth of a crack through the thickness of a vessel shell is a very important attribute of shear wave UT.…
Shear wave UT is very useful for detecting cracks that have developed during service. Figure 700-19 illustrates how shear wave UT, calibrated according to Figure…
Shear wave UT is calibrated using a test block manufactured from a material similar to the workpiece (i.e., with the same velocity of sound), that…
Shear wave UT is used primarily to detect and determine the size of cracks that have developed during service. Forms of deterioration that can result…
The use of longitudinal wave UT for detecting, locating, and determining the size of hydrogen blisters is illustrated in Figure 700-17. The blisters are internal…
Figure 700-16 illustrates the use of longitudinal UT for determining the remaining thickness of a corroded shell. If the transducer is placed on a location…
Calibration of longitudinal wave UT consists of developing a “distance amplitude curve (DAC)” for the instrument and transducer, using test blocks manufactured from a material…