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CWB Welding Inspector Lvl 2 > Chapter 11 Ultrasonic Inspection > Flashcards

Chapter 11 Ultrasonic Inspection Flashcards

1
Q
  1. If an ultrasonic wave in a block of steel has a wavelength of 1.3 mm and travels at a velocity of 5.85 x 10° m/s, what is the frequency?
A

5.85/1.3 = 4.5Mhz

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2
Q
  1. Do transverse waves in a solid travel faster or slower than longitudinal waves?
A

Slower

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3
Q
  1. If the amplitude of a wave is reduced to 2596, what is the corresponding drop in dB? (Hint: you can figure it out from the information in Section 2.5 but you could also use logarithm tables or a calculator).
A

12dB

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4
Q
  1. Name one piezoelectric material.
A

Quartz and lead metaniobate

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5
Q
  1. Why is good acoustic contact between the transducer and the test specimen needed?
A

Ultrasonic waves of the frequency used in inspection do not travel far in air, so good coupling between the transducer and the specimen is needed

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6
Q
  1. Draw a block diagram of the basic pulse-echo equipment from memory, then compare your sketch with Figure 217 in Section 3.1.
A
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7
Q
  1. In what unit is the gain control (or attenuator) marked?
A

dB (Decibels)

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8
Q
  1. Which type of display gives a cross-sectional view showing the length and depth of discontinuities?
A

B-Scan

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9
Q
  1. Give an example of a system where the entire specimen is immersed in water, which acts as the couplant.
A

On-line examination of plate for defects such as laminations in a steel mill

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10
Q
  1. Acoustic emission relies on detecting very small amounts of mechanical energy released from such things as growing cracks or structural discontinuities under load.

a. True
b. False

A

a. True

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11
Q
  1. Why should most ultrasonic examinations of welds begin with a search of the plate with a normal probe?
A

To identify plate defects such as laminations that could interfere with examination of the weld with an angle probe.

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12
Q
  1. When using an angle probe, when would it be necessary to bounce the beam off the back wall?
A

Allows inspection of upper part of weld

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13
Q
  1. Difficulties with UT can arise when welds have backing bars due to reflections from corners, internal reflections in the bars, etc.

a. True
b. False

A

a. True

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14
Q
  1. When working to CSA W59, to what must the ultrasonic operator be certified?
A

CAN/CGSB-48.9712, Certification of Nondestructive Testing Personnel

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15
Q
  1. What two features of an angle probe can be calibrated or checked using the IIW block?
A

Exit point (index point) and angle

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16
Q
  1. Distance calibration using an IIW block for a normal (longitudinal mode) probe requires the probe to be placed on the:

a. top of the block such that the beam reflects from the 1.5 mm hole.
b. other edge to reflect off the curved end.
c. side to reflect off the back wall.

A

c. side to reflect off the back wall.

17
Q
  1. For the transverse mode, what reflector in the IIW block is used to calibrate sensitivity according to CSA W59?
A

1.5 mm side hole

18
Q
  1. As the direction of approach of the beam is changed, the amplitude of the wave reflected from a spherical pore can be expected to:

a. rise to a maximum then decrease.
b. rise to a peak only if the probe were moved in the plane of the plate.
c. not vary significantly.

A

c. not vary significantly.

19
Q
  1. In most codes and standards the acceptance or rejection of a discontinuity is based on whether it is shown that it will cause failure.

a. True
b. False

A

b. False

20
Q
  1. For imperfections interpreted as incomplete fusion, the maximum acceptable length according to ASME Section VIII, Div. 1 is:

a. 20 mm.
b. 1/3 T (where T is weld thickness).
c. neither of the above. Incomplete fusion imperfections are unacceptable regardless of length.

A

c. neither of the above. Incomplete fusion imperfections are unacceptable regardless of length.

21
Q
  1. To reduce the height of an indication on the screen by 50%, you would turn the gain control (or attenuator) through:

a. 2 dB.
b. 50 dB.
c. 60 dB.
d. 20 dB.
e. 6 dB.

A

e. 6 dB.

22
Q
  1. If you are examining a groove weld in a plate from one surface with an angle probe, you would examine the upper portion of the weld by:

a. placing the probe on the weld reinforcement.
b. moving the probe as close as possible to the weld.
c. using a normal probe close to the edge of the weld.
d. moving the probe away from the weld so the beam bounces off the lower surface to strike the upper portion of the weld.
e. none of the above. The upper portion cannot be examined.

A

d. moving the probe away from the weld so the beam bounces off the lower surface to strike the upper portion of the weld.

23
Q
  1. The frequency of a sound passing through a material with an ultrasonic velocity of 4.65 x 10° m/s and a wavelength of 1.8 mm is:

a. 26 MHz.
b. 2,600 km/s.
c. 2.6 kHz.
d. 2.6 MHz.

A

d. 2.6 MHz.

24
Q
  1. Can we say that the action of a hammer pounding onto the surface of a metal is just about the same as the action exerted by ultrasonic probe?

a Yes
b. No

A

a Yes

25
Q
  1. Sound wave is a mechanical vibration.

a. No, it is a radiation vibration
b. No, it is like gamma radiation
c. Yes, it is like spiritual vibration
d. Yes, it is vibration that has characteristic frequency, that is, a number of vibrations per second

A

d. Yes, it is vibration that has characteristic frequency, that is, a number of vibrations per second

26
Q
  1. Can shear waves operate in similar ways to longitudinal waves in the water?

a. No, because its not enough force of attraction between the atoms of water
b. Yes, because there are a lot of attraction between the atoms
c. Yes, they certainly can operate in similar ways
d. Yes, because shear waves cause more vibration than longitudinal waves

A

a. No, because its not enough force of attraction between the atoms of water

27
Q
  1. In UT probe of the transverse wave mode, is the angle of incidence always equal to the angle of refraction?

a. Yes
b. The angle of refraction is always more
c. The angle of incidence is always more
d. Both angles are regulated by frequency

A

b. The angle of refraction is always more

28
Q
  1. The amplifier in the ultrasonic testing circuit performs the following task:

a. It regulates the vertical beam deflection
b. It regulates the horizontal time-base
c. It regulates the gate’s size
d. It regulates the frequency

A

a. It regulates the vertical beam deflection

29
Q
  1. Other display methods used for UT inspection are B-scan, C-scan and P-scan. Which one of these scans provide a permanent record of the test when automatic testing is used?

a. The B-scan
b. The P-scan
c. None of them
d. The C-scan

A

d. The C-scan

30
Q
  1. Is it possible to use acoustic emission method for global monitoring of the structure service life?
A

Yes

CWB Welding Inspector Lvl 2 (13 decks)

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