TWI TRAINING & CERTIFICATION
Phased Array AUT UT Coursework 1
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Q. 1
When preparing for a pipeline inspection what must you do to ensure you get the correct
angles in the test piece once you have decided on the best angles for the bevel?
a.
b.
c.
d.
Q.2
When determining acoustic velocities in pipe steel for a pipeline project you must use an SH
shear wave probe. The pipe steel is birefringent and gives more than one velocity. The
velocity that you must determine in the steel to get the best results for correct shear wave
angles is the __________ velocity.
a.
b.
c.
d.
Q. 3
2.4mm
2.9mm
3.2mm
3.5mm
When setting gates for the fusion line (strip charts) channels not all of the gates will have the
same length. Which gates are sometimes made longer?
a.
b.
c.
d.
Q.6
5%
20%
30%
40%
When designing an inspection technique for a 15.5mm thick CRC weld bevel it would typically
use 8 zones. What would the Fill zone height be (closest approximation)?
a.
b.
c.
d.
Q.5
SH slow wave
SH fast wave
Compression wave
Surface wave
What is the gate threshold level normally set, for collecting time (TOF) information on the strip
chart channels?
a.
b.
c.
d.
Q. 4
Determine the number of zones to be used for the welds to be tested
Determine the acoustic velocity of the pipe steel
Determine the acoustic velocity of the plastic in the wedge
Both b and c are required
Amplitude gates for the Fill Zones
Time gates for the Fill Zones
Time gates for the Root &/or cap zone
Amplitude gates for the Root &/or cap zone
The decibel is :
a
b
c
a. An absolute measurement of sound
b. A logarithmic unit of comparison
c. An absolute unit of power
d. (a) and (b)
TWI AUT CW 1 Issue 0
Q.7
When using the standard 60 element linear array phased array probe what effect on the
vertical beam size at the focal spot does a shortening of the focal distance have?
a.
b.
c.
d.
Q. 8
What is the normal (and maximum) sample interval along the girth used in girth weld
inspections in the zonal technique?
a.
b.
c.
d.
Q.9
It decreases
It increases
no change results in the vertical direction
none of the above, it is unpredictable
0.5mm
1mm
2mm
3mm
What ultimately determines the accuracy of the position of a signal in the time gate?
a.
b.
c.
d.
the encoder
the reference target amplitude
probe frequency
A to D digitising frequency
Q.10 What is the purpose of storing the scanning head on a heated calibration block between
scans?
a.
b.
c.
d.
Q.11.
Reduce attenuation in the wedge
Maintain a steady temperature on the wedge
Prevent electrical shock by reducing humidity in the probe wedge
Keep the scanner technicians hands warm
In a 32/128 phased array instrument what is the maximum number of elements that can be
used in a single focal law?
a. 9
b. 20
c. 32
d. 128
Q.12
When analysing scan data using the pipeWIZARD computer software, what colour is the
measurement cursor?
a.
b.
c.
d.
Q13
Red
Blue
Green
Black
With frequency remaining constant the length of the near field will decrease if :
a.
b.
c.
d.
Probe diameter increases
Probe diameter decreases
Beam spread increases
Quartz is utilised as the transducer
TWI AUT CW 1 Issue 0
Q.14
Accidentally a phased array probe that has been correctly calibrated is banged slightly so its
position is adjusted slightly (1mm) away from the ideal weld centreline. Which focal law is
most likely going to require re-calibration?
a.
b.
c.
d.
Q.15
e
Q.16
What is the interval between calibration verifications based on when performing AUT?
a.
b.
c.
d.
time
number of welds
number of weld passes completed
(a) and (b)
What is the nominal incident angle for a wedge used with a PipeWIZARD 60 element 7.5MHz
probe?
a.
b.
c.
d.
Q.17
Root
LCP
all tandem fills
all zones will be requiring a re-calibration
33.7 degrees
43.7 degrees
53.7 degrees
63.7 degrees
How do you adjust the stand off (surface distance from the target) when maximising a
response from a calibration target using the phased array system.
a. Change the start element
b. Change the delay between the elements used in the focal law
c. Loosen the locking nut and reposition the entire probe mounting
d. stand off cannot be adjusted
Q.18
When setting up for a normal inspection using 2mm diameter Flat Bottom Holes, what
amplitude do you normally set the amplitude threshold to cause the time gate signal to change
from green to red?
a.
b.
c.
d.
20%
40%
50%
80%
TWI AUT CW 1 Issue 0
Figure 1
Q.19
In figure 1 above the Upstream probes have been set too close to the weld centreline on the
upstream side, how does the operator know this has happened from the strip chart scan data?
a.
b.
c.
d.
f
g
Q.20
The root geometry signal appears on the upstream side stripchart
The root geometry signal appears on the downstream side stripchart
There is a loss of coupling
It is not possible to determine
The PipeWIZARD phased array system is based on which technique?
a.
b.
c.
d.
Amplitude height
Time of flight
Zonal discrimination
A and C scan imaging
TWI TRAINING & CERTIFICATION
TWI AUT CW 1 Issue 0
Phased Array AUT UT Coursework 1
Students Name:
Date:
Question
No.
1
Answer
Question No.
14
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15
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TWI TRAINING & CERTIFICATION
Phased Array AUT UT Coursework 1
TWI AUT CW 1 Issue 0
Answer
Students Name:
Date:
Question
No.
1
Answer
Question No.
Answer
14
15
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20
10
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TWI AUT CW 1 Issue 0
