UT 263 CARDS HAROLD BENNETT Flashcards
Ultrasonic Testing
1
Q
“100,000 cycles per second” can be written:
A
100 kilohertz
2
Q
“25 million cycles per second” can also be stated as:
A
25 megahertz
3
Q
A smooth flat discontinuity whose major plane is not perpendicular to the direction of sound propagation may be indicated by:
A
1. An echo amplitude comparable in magnitude to the back surface reflection.
2. A complete loss of the back surface reflection.
3. An echo amplitude larger in magnitude than the back surface reflection.
All of the above.
4
Q
A 25-megahertz search unit would most likely be used during:
A
IMMERSION TESTING
5
Q
A 45 degrees shear angle beam transducer produces a wave in the metal which is polarized:
A
1. PERPENDICULAR TO THE DIRECTION OF PROPAGATION and
2. AT 45 DEGREE TO THE ENTRY SURFACE.
6
Q
A B-scan display shows the relative:
A
DISTANCE A DISCONTINUITY IS FROM THE TRANSDUCER and
ITS LENGTH IN THE DIRECTION OF TRANSDUCER TRAVEL
7
Q
A diagram in which the entire circuit stage or sections are shown by geometric figures and the path of the signal or energy by lines and/or arrows is called a:
A
BLOCK DIAGRAM
8
Q
A disadvantage of using natural quartz crystals in a search unit is that:
A
It is the least effective generator of ultrasonic energy of all commonly used materials.
9
Q
A discontinuity is located having an orientation such that its long axis is parallel to the sound beam. The indication from such a discontinuity will be:
A
SMALL IN PROPORTION TO THE LENGTH OF THE DISCONTINUITY.
10
Q
A discontinuity that occurs during the casting of molten metal which may be caused by the splashing, surging, interrupted pouring, or the meeting of two streams of metal coming from different directions is called:
A
A COLD SHUT
**Cold shut is a defect in welding or casting **
11
Q
A grouping of a number of crystals in one search unit, with all contact surfaces in the sample plane, and vibrating in phase with each other to act as a single transducer is called a:
A
Crystal mosaic
12
Q
A hole produced during the solidification of metal due to escaping gases is called:
A
A blow hole
13
Q
A longitudinal ultrasonic wave is transmitted from water into steel at an angle of 5 degrees from the normal. In such a case the refracted angle of the transverse wave is:
A
Less than the refracted angle of the longitudinal wave.
14
Q
A material used between the face of a search unit and the test surface to permit or improve the transmission of ultrasonic vibrations from the search unit to the material being tested is called:
A
A couplant
15
Q
A plan view display or recording of a part under examination is called:
A
A C-scan display.
A C-scan is one of the most sophisticated ways to view ultrasonic testing data. It is a three-dimensional representation of the material thickness plotted over position both horizontally and vertically. In essence, C-scans are visual maps that reveal patterns of degradation in the asset.
16
Q
A point, line, or surface of a vibrating body marked by absolute or relative freedom from vibratory motion is referred to as:
A
A node
17
Q
A quartz crystal cut so that its major faces are parallel to the Z and Y axes and perpendicular to the X axis is called:
A
A X-cut crystal
18
Q
A screen pattern containing a large number of low-level indications (often referred to as “hash”) could be caused by:
A
Coarse grained material
19
Q
A search unit containing three or more individual transducer elements is often referred to as a:
A
Mosaic transducer
20
Q
A search unit with a frequency greater than 10 MHz will most likely be used during:
A
An immersion test
21
Q
A second name for Rayleigh waves is:
A
Surface waves
Rayleigh waves are also known as Lamb waves, or surface waves
22
Q
A separate time base line imposed on the viewing screen of some ultrasonic testing instruments that permits measurement of distances is often referred to as:
A
A marker
23
Q
A set of standard reference blocks with the same geometrical configuration and dimensions other than the size of the calibration reflectors, e.g., flat bottom holes, is called a set of:
A
Area/Amplitude Standards.
24
Q
A short burst of alternating electrical energy is called:
A
A pulse
25
**A special scanning device with the transducer mounted in a tire- like container filled with couplant is commonly called;**
**A wheel search unit**
26
**A term used in ultrasonics to express the rate at which sound waves pass through various substances is:**
**Velocity**
27
**A term used to describe numerous small indications on the cathode ray tube screen resulting from test part structure, numerous small discontinuities or both is often referred to as:**
**Multiple back reflections**
28
**A term used to describe the ability of an ultrasonic testing system to distinguish between the entry surface response and the response of discontinuities near the entry surface is:**
**Resolution**
29
**A test method employing two separate search units on opposite surfaces of the material being tested is called:**
**Through-transmission testing**
30
**A test method in which the parts to be inspected are placed in a water bath or some other liquid couplant is called:**
**Contact testing**
31
**A type of data presentation most likely to be used with a high speed automatic scanning system is:**
**A C-scan presentation.**
32
**Acoustic energy propagates in different modes. Which of the following represents a mode?**
**1. Longitudinal wave
2. Shear wave
3. Surface wave
4. All of the above**
33
**Acoustic velocities are primarily described by:**
**1. DENSITY
2. ELASTICITY
3. both A and B**
34
**Acoustical lenses are commonly used for contour correction. When scanning the inside of a pipe section by the immersion method, which of the following lens types would be used?**
**Convex**
35
**All other factors being equal, which of the following modes of vibration has the greatest velocity?**
**Longitudinal wave**
36
**An advantage of using a ceramic transducer in search units is that:**
**It is one of the most efficient generators of ultrasonic energy.**
37
**An advantage of using lithium sulfate in search units it that:**
**It is one of the most efficient receivers of ultrasonic energy.**
38
**An amplitude type gate is necessary for all:**
**Automatic examinations.**
39
**An A-scan CRT display which shows a signal both above and below the sweep line is called a:**
**RF display**
40
**An electron tube in which a beam of electrons from the cathode is used to reproduce an image on a fluorescent screen at the end of the tube is referred to as:**
**A cathode ray tube**
41
**An ultrasonic test using a straight beam contact search unit is being conducted through the thickness of a flat part such as a plate. This test should detect:**
**Laminar-type flaws with major dimensions parallel to the rolled surface.**
42
**An ultrasonic testing instrument that displays pulses representing the magnitude of reflected ultrasound as a function of time or depth of metal is said to contain:**
**An A-scan presentation.**
## Footnote
**The A-Scan is a one-dimensional presentation of time versus the amplitude on the UT machine screen. It shows the existence of flaws (if any present during scanning), and their position, and also gives an estimate of their sizes.**
43
**An ultrasonic testing technique in which the transducer element is not parallel to the test surface is called:**
**Angle beam testing**
44
**Another name for a compressional wave is:**
**Longitudinal wave**
45
**Another name for Fresnel Zone is:**
**Near Field**
46
**As frequency increases in ultrasonic testing, the angle of beam divergence of a given diameter crystal:**
**Decreases.**
47
**As frequency increases in ultrasonic testing, the angle of beam divergence of a given diameter crystal:**
**Decreases**
48
**As the grain size increases in a material, its principal effect in ultrasonic testing is on:**
**The attenuation.**
49
**As the impedance ratio of two dissimilar materials increases, the percentage of sound coupled through an interface of such materials:**
**Decreases.**
50
**As the radius of curvature of a curved lens is increased, the focal length of the lens will:**
**Increase**
51
**As transducer diameter decreases, the beam spread:**
**Increases**
52
skip
skip skip
53
**At an interface between two different materials, an impedance difference results in:**
**Division of sound energy into transmitted and reflected modes**
54
**Attenuation is a difficult quantity to measure accurately, particularly in solid materials, at the test frequencies normally use The overall result usually observed includes other loss mechanisms which can include:**
**1. BEAM SPREAD
2. COUPLANT MISMATCH
3. TEST PIECE GEOMETRY
All of the above**
55
**Attenuation is a:**
**Test material parameter.**
56
**Beam divergence is a function of the dimensions of the crystal and the wavelength of the beam transmitted through a medium, and it:**
**increases if the frequency or crystal diameter is decrease**
57
**Compensation for the variation in echo height related to variations in discontinuity depth in the test material is known as:**
**Distance amplitude correction**
58
**Compression waves whose particle displacement is parallel to the direction of propagation are called:**
**Longitudinal waves**
59
**Delay-tip(stand-off)type contact search units are primarily used for:**
**Thickness measurement of flaw detection in thin materials.**
60
**During a straight beam ultrasonic test a discontinuity indication is detected which is small in amplitude compared to the loss in amplitude of back reflection. The orientation of this discontinuity is probably:**
**Such that complete loss of back reflection will result.**
61
**During straight beam testing, test specimens with non-parallel front and back surfaces can cause:**
**Partial or total loss of back reflection**
62
**During ultrasonic testing by the immersion method, it is frequently necessary to angulate the search unit when a discontinuity is located in order to:**
**Obtain a maximum response if the discontinuity is not originally oriented perpendicular to the ultrasonic beam.**
63
**Entry surface resolution is a characteristic of an ultrasonic testing system which defines its ability to:**
**Detect discontinuities located just beneath the entry surface in the part being teste**
64
**For aluminum and steel the longitudinal velocity is approximately ____________ the shear velocity:**
**Twice**
65
**For discontinuity geometries other than flat, the echo amplitude is usually from that observed for a flat defect, of similar orientation perpendicular to the sound beams.**
**Decreased**
66
**Gas discontinuities are reduced to flat discs or other shapes parallel to the surface by:**
**Rolling**
67
**Heat conduction, viscous friction, elastic hysteresis, and scattering are four different mechanisms which lead to:**
**attenuation**
68
**If a 5.0 MHz transducer is substituted for a 2.25 MHz transducer, what would be the effect on the wavelength of a longitudinal mode wave produced in the test specimen?**
**The wavelength would remain constant.**
69
**If the major dimensions of a discontinuity in a 6-inch thick aluminum plate lie parallel to the entry surface at a depth of 3 inches, it will be best detected by:**
**A straight beam test**
70
**If the velocity of a longitudinal mode wave in a given homogeneous material is .625 cm/micro se at 1/2 inch below the surface, what is the velocity at 2 inches below the surface?**
**The same as the velocity at 1/2 inch.**
71
**In a basic pulse-echo ultrasonic instrument, the component that coordinates the action and timing of other components is called a:**
**Synchronizer, clock, or timer.**
72
**In a basic pulse-echo ultrasonic instrument, the component that produces the voltage that activates the search unit is called:**
**Pulser**
73
**In a basic pulse-echo ultrasonic instrument, the component that produces visible signals on the CRT which are used to measure distance is called a:**
**Marker circuit**
74
**In a basic ultrasonic test pattern (A-scan) for contact testing, the initial pulse (assume no sweep delay is used):**
**IS THE HIGH INDICATION ON THE EXTREME LEFT SIDE OF THE SCREEN that represents the entry surface of the inspected part.**
75
**In a basic-pulse-echo ultrasonic instrument, the voltage producing component which activates the search unit is called:**
**Sweep circuit**
76
**In a B-scan display, the length of a screen indication from a discontinuity is related to:**
**The discontinuity's length in the direction of the transducer travel.**
77
**In a liquid medium, the only mode of vibration that exists is:**
**Longitudinal**
78
**In a material with a given velocity, when frequency is increased, the wavelength will:**
**Decrease**
79
**In a test where the transducer is not perpendicular to the inspection surface, the angle of incidence is equal to:**
**The angle of reflection.**
80
**In addition to other functions, a probe manipulator in a mechanical immersion scanning unit permits:**
**Detection of obliquely-oriented discontinuities.**
81
**In an A-scan presentation, the horizontal base line represents the:**
**Elapsed time or distance**
82
**In an A-scan presentation, the horizontal line formed by the uniform and repeated movement of an electron beam across the fluorescent screen of a cathode ray tube is called:**
**A sweep line.**
83
**In an automatic scanning immersion unit, the bridge or carriage serves to:**
**Support the manipulator and scanner tube and to move it about transversely and longitudinally.**
84
**In an immersion inspection of raw material, the water travel distance should be:**
**Equal to the water travel distance used in setting up on the reference standards.**
85
**In an immersion test of a piece of steel or aluminum, the water distance appears on the display as a fairly wide space between the initial pulse and the front surface reflection because of:**
**Reduced velocity of sound in water as compared to test specimen.**
86
**In an ultrasonic instrument, the number of pulses produced by an instrument in a given period of time is known as the:**
**Pulse repetition rate.**
87
**In cases where the diameter of tubing being inspected is smaller than the diameter of the transducer, what can be used to confine the sound beam to the proper range of angles?**
**A collimator.**
88
**In contact testing, defects near the entry surface cannot always be detected because of:**
**The dead zone.**
## Footnote
**Another name for the dead zone is the near field or near-surface blind zone. This area is close to the transducer, where the initial pulse and its reflections can interfere with defect detection.**
89
**In contact testing, shear waves can be induced in the test material by:**
**Using a transducer mounted on a plastic wedge so that sound enters the part at an angle.**
90
**In contact testing, the entry surface indication is sometimes referred to as:**
**1. The initial pulse
2. The "main bang" or transmitter pulse
Both A and B**
91
In general, discontinuities in wrought products tend to be oriented:
In the direction of grain flow.
92
In general, which waves will travel around gradual curves with little or no reflection from the curve?
Surface waves.
93
In immersion testing a wetting agent is added to the water to:
Help eliminate the formation of air bubbles.
94
In immersion testing in a small tank, a manually operated manipulator is used to:
Set the proper water path Set the proper transducer angle Both A and B
95
In immersion testing irrelevant or false indications caused by contoured surfaces are likely to result in a:
Broad-based indication.
96
In immersion testing, the accessory equipment to which the search cable and the search unit are attached is called a:
Search tube or scanning tube.
97
In immersion testing, the most commonly used couplant is:
Water
98
In immersion testing, the near field effects of a transducer may be eliminated by:
Using an appropriate water path.
99
In immersion testing, the position of the search unit is often varied to transmit sound into the test part at various angles to the front surface. Such a procedure is referred to as:
Angulation.
100
In immersion testing, verification that the search unit is normal to a flat entry surface is indicated by:
Maximum reflection from the entry surface
101
In inspecting a 4-inch diameter threaded steel cylinder for radial cracks extending from the root of the threads, it would be preferable to transmit:
Longitudinal waves from the end of the cylinder and perpendicular to the direction of the thread roots.
102
In steel, the velocity of sound is greatest in which of the following modes of vibration?
Longitudinal
103
In straight (normal) beam contact testing, a reduction in the back surface reflection amplitude could indicate:
Inadequate coupling. A flaw which is not normal to the beam. A near surface defect that cannot be resolved from the main bang (initial pulse). All of the above
104
In straight beam pulse echo testing a discontinuity with a rough reflecting surface perpendicular to the incident wave will have what effect on the detected signal in comparison to a smooth flat-bottom hole of the same size?
Decrease it.
105
In the basic pulse-echo instrument, the synchronizer, clock or timer circuit will determine the instrument's:
pulse repetition rate
106
In the immersion technique, the distance between the face of the transducer and the test surface (water path) is usually adjusted so that the time required to send the sound beam through the water.
Is greater than the time required for the sound to travel through the testpiece.
107
In ultrasonic testing, a liquid coupling medium between the crystal surface and the part surface is necessary because:
Lubricant is required to minimize wear on the crystal surface.
108
In ultrasonic testing, the time duration of the transmitted pulse is referred to as:
The pulse length or pulse width
109
In which medium listed below would the velocity of sound be lowest?
Air
110
In which zone does the amplitude of an indication from a given discontinuity diminish exponentially as the distance increases?
Far field zone
111
Increasing the length of the pulse used to activate the search unit will:
Increase the strength of the ultrasound but decrease the resolving power ofthe instrument.
112
Inspection of castings is often impractical because of:
coarse grain structure.
113
It is possible for a discontinuity smaller than the transducer to produce indications of fluctuating amplitude as the search unit is moved laterally if testing is being performed in the:
Near field
114
Lamb waves can be used to detect:
Laminar-type defects near the surface of a thin material
115
Lamb waves may be used to inspect:
thin sheet
116
Large grains in a metallic test specimen usually result in:
Decrease or loss of back surface reflection. Large "hash" or noise indications. Decrease in penetration. All of the above.
117
Longitudinal wave velocity in water is approximately one-fourth the velocity in aluminum or steel. Therefore the minimum water path should be:
One-fourth the test piece thickness plus 1/4 inch.
118
Low frequency sound waves are not generally used to test thin materials because of:
Poor near-surface resolution.
119
Metal blocks which contain one or more drilled holes to simulate discontinuities are called:
Reference blocks
120
Most basic pulse-echo ultrasonic instruments use:
An A-scan presentation.
121
Most commercial ultrasonic testing is accomplished using frequencies between:
1 and 25 megahertz
122
Moving a search unit over a test surface either manually or automatically is referred to as:
Scanning
123
Of the following scan types, which one can be used to produce a recording of flaw areas superimposed over a plan view of the test piece?
C-scan
124
Of the following sound wave modes, which one has multiple or varying wave velocities?
Lamb waves
125
Of the piezoelectric materials listed below, the most efficient sound receiver is:
Lithium sulfate
126
Of the piezoelectric materials listed below, the most efficient sound transmitter is:
Barium titanate
127
On an A-scan display, the "dead zone," refers to:
The distance covered by the front surface pulse width and recovery time.
128
On an A-scan display, what represents the intensity of a reflected beam?
Signal amplitude
129
On many ultrasonic testing instruments, an operator conducting an immersion test can remove that portion of the screen presentation that represents water distance by adjusting a:
Sweep delay control.
130
On the area-amplitude ultrasonic standard test blocks, the flat- bottomed holes in the blocks are:
Different in diameter, increasing by 1/64-inch increments from the No. "1" block to the No. "8" block.
131
Rayleigh waves are influenced most by defects located:
Close to or on the surface
132
Reflection indications from a weld area being inspected by the angle-beam technique may represent:
Porosity Cracks Weld bead All three of the above
133
Rough entry surface conditions can result in:
A loss of echo amplitude from discontinuities. An increase in the width of the front surface echo. Both A and
134
Search units constructed with a plastic wedge or standoff between the transducer element and the test piece are commonly used for:
Dual transducer straight beam contact testing. Angle beam contact testing. Surface wave contact testing. All of the above.
135
Since the velocity of sound in aluminum is approximately 245,000 in/sec, how long does it take for sound to travel through 1 inch of aluminum?
4 microseconds
136
Sound can be focused by means of special curved adapters located in front of the transducer element. These adapters are referred to as:
Acoustic lenses
137
Sound waves of a frequency beyond the hearing range of the human ear are referred to as ultrasonic waves or vibrations, and the term embraces all vibrational waves of frequency greater than approximately:
20,000 hertz
138
Surface (Rayleigh) waves traveling on the top face of a block are attenuated by the presence of:
A curved surface A heavy couplant Both B and C
139
Surface (Rayleigh) waves traveling on the top face of a block:
Are reflected from a sharp edge corner.
140
Surface waves are reduced to an energy level of approximately 1/25 of the original power at a depth of:
One wavelength.
141
The acoustic impedance is:
The product of the density of the material and the velocity of sound in the material.
142
The acoustic impedance of a material is used to:
Find the amounts of sound energy reflected and refracted through an interface.
143
The advantages of immersion testing include which of the following?
Inspection speed increase Ability to control and direct sound beams. Adaptability for automated scanning. All of the above.
144
The amount of beam divergence from a crystal is primarily dependent on the:
Frequency and crystal size
145
The angle formed by an ultrasonic wave as it enters a medium of different velocity than the one from which it came and a line drawn perpendicular to the interface between the two media is called:
The angle of refraction.
146
The angle of incidence is:
Equal to the angle of reflection
147
The angle of reflection is:
Equal to the angle of incidence.
148
The angular position of the reflecting surface of a planar discontinuity with respect to the entry surface is referred to as:
The orientation of the discontinuity.
149
The attenuation of energy within a material in the far field of the ultrasonic beam may be expressed as the:
Exponential decay
150
The boundary between two different materials which are in contact with each other is called:
An interface
151
The cable that connects the ultrasonic instrument to the search unit is specially designed so that one conductor is centered inside another. The technical name for such a cable is:
Coaxial cable
152
The cathode ray tube screen will display a plan view of the part outline and defects when using:
A C-scan presentation.
153
The change in direction of an ultrasonic beam when it passes from one medium to another whose velocity differs from that of the first medium is called:
Refraction
154
The coated inside surface of the large end of a cathode ray tube which becomes luminous when struck by an electron beam is called:
A CRT screen
155
The component in a conventional immersion system which spans the width of the immersion tank is called:
A bridge.
156
The crystal thickness and transducer frequency are relate The thinner the crystal:
The higher the frequency
157
**The depth of a discontinuity cannot be determined when using**
**Through transmission testing method**
158
The differences in signals received from identical reflectors at different material distances from a transducer may be caused by:
Near field effects.
159
The electronic circuitry that allows selection and processing of only those signals relating to discontinuities that occur in specific zones of a part is called:
An electronic gate.
160
The equation describing wavelength in terms of velocity and frequency is:
Wavelength = Velocity / Frequency
161
The existence of a discontinuity will not produce its specific indication on the CRT screen when using the:
Immersion testing method
162
The expansion and contraction of a magnetic material under the influence of a changing magnetic field is referred to as:
Magnetostriction
163
The formula used to calculate the angle of refraction within a material is called:
Snell's law
164
The fundamental frequency of a piezoelectric crystal is primarily a function of:
the thickness of the crystal.
165
The gradual loss of sonic energy as the ultrasonic vibrations travel through the material is referred to as:
Attenuation
166
The incident angles at which 90 degrees refraction of longitudinal and shear waves occurs are called:
The critical angles.
167
The indication on the cathode ray tube(CRT) which represents the far boundary of the material being tested is called:
The back surface reflection
168
The interference field near the face of a transducer is often referred to as the:
Fresnel zone.
169
The length of the zone adjacent to a transducer in which fluctuations in sound pressure occur is mostly affected by:
The frequency of the transducer The diameter of the transducer Both A and B
170
The maximum scanning speed possible is primarily determined by:
The pulse repetition rate of the test instrument.
171
The most commonly used method of producing shear waves in a test part when inspecting by the immersion method is:
By angulating the search tube to the proper angle.
172
The motion of particles in a shear wave is:
Transverse to the direction of beam propagation.
173
The number of complete waves which pass a given point in a given period of time (usually one second) is referred to as the:
Frequency of a wave motion
174
The only significant sound wave mode that will travel through a liquid is:
Longitudinal
175
The phenomenon by which a wave strikes a boundary and changes the direction of its propagation within the same medium is referred to as:
Reflection
176
The phenomenon whereby an ultrasonic wave changes direction when the wave crosses a boundary between materials with different velocities is called:
Refraction
177
The piezoelectric material in a search unit which vibrates to produce ultrasonic waves is called:
A transducer element or crystal
178
The primary purpose of reference blocks is to:
Obtain a common reproducible signal.
179
The primary requirement of a paintbrush transducer is that:
the intensity of the beam pattern not vary greatly over the entire length of the transducer.
180
The process of adjusting an instrument or device to a reference standard is referred to as:
Calibration
181
The process of comparing an instrument or device with a standard is called:
Calibration
182
The product of the acoustic velocity of sound in a material and the density of the material is the factor that determines the amount of reflection or transmission ofltrasonic Energy when it reaches an interface. This term is called:
Acoustic impedance
183
The proper interpretation and evaluation of the presented defect signals are essential to any nondestructive test. A common method for the estimation of defect size is the use of a:
Reference standard
184
The pulser circuit in an ultrasonic instrument is used to:
Activate the transducer.
185
The random distribution of crystallographic direction in alloys with large crystalline structure is a factor in determining:
Acoustic noise levels Selection of test frequency Scattering of sound All of the above
186
The ratio between the wave speed in one material and the wave speed in a second material is called:
The index of refraction.
187
The ratio of stress to strain in a material within the elastic limit is called:
Young's modulus The Modulus of elasticity Both A and B
188
The ratio of the velocity of sound in water compared to that for aluminum or steel is approximately:
1:4
189
The reference holes in standard aluminum area-amplitude Ultrasonic test blocks contain:
Flat-bottomed holes
190
The resolving power of a search unit is directly proportional to its:
band width
191
The scattering of the ultrasonic energy of an ultrasonic beam due to reflection from a highly polished surface is called:
Dispersion
192
The simple experiment where a stick in a glass of water appears disjointed at the water surface illustrates the phenomenon of:
Refraction
193
The total energy losses occurring in all materials is called:
Attenuation
194
The ultrasonic test method in which finger damping is most effective in locating a discontinuity is:
Surface wave
195
The velocity of longitudinal waves will be highest in:
Aluminum
196
The velocity of sound in a material is dependent upon the:
Material properties
197
The velocity of sound waves is primarily dependent on:
The material in which the sound is being transmitted and the mode of vibration
198
The velocity of surface waves is approximately ________ the velocity of shear waves in the same material.
Nine-tenths
199
The vertical linear range of a test instrument may be determined by obtaining ultrasonic responses from:
A set of area-amplitude reference blocks.
200
The wavelength of an ultrasonic wave is:
directly proportional to velocity and inversely proportional to frequency.
201
Thin sheet may be inspected with the ultrasonic wave directed normal to the surface by observing:
The multiple reflection pattern.
202
To evaluate and accurately locate discontinuities after scanning a part with a paintbrush transducer, it is generally necessary to use a:
Search unit with a smaller crystal.
203
To prevent the appearance of the second front surface indication before the first back reflection when inspecting aluminum by the immersion method (water is used as a couplant),it is necessary to have a minimum of at least one inch of water for every:
Four inches of aluminum.
204
To vary or change the wavelength of sound being used to test a part, you would change the:
Sound wave frequency.
205
Ultrasonic data which is presented in a form representative of the cross-section of the test specimen is called:
A B-scan presentation.
206
Ultrasonic testing of material where the search unit is in direct contact with the material being tested may be:
Straight beam testing Surface wave testing Angle beam testing All of the above
207
Ultrasonic vibrations are commonly used to:
Examine materials for discontinuities. Examine materials for thickness. Examine materials for mechanical properties. All of the above.
208
Ultrasonic vibrations can be propagated only in the longitudinal mode in which of the following media?
Machine oil
209
Ultrasonic waves that travel along the surface of a material and whose particle motion is elliptical are called:
Rayleigh waves
210
Ultrasonic waves transmitted into and received from the test material in the form of repetitive bursts of acoustic energy is called:
Pulse-echo testing
211
Ultrasonic wheel units may be used for which of the following types of examination?
Straight or longitudinal examination Angle-beam or shear wave examination Surface wave or Rayleigh wave All of the above
212
Under most circumstances, which of the following frequencies would result in the best resolving power?
25 megahertz
213
Using a pulse-echo technique, if the major plane of a flat discontinuity is oriented at some angle other than perpendicular to the direction of sound propagation, the result may be:
Loss or lack of a received discontinuity echo
214
Water travel distance for immersion inspections should be:
Such that the second front reflection does not appear between the first front and back reflections.
215
What can cause irrelevant indications on the cathode ray tube?
Contoured surfaces Edge effects Surface conditions All of the above
216
What is the most common type of data display used for ultrasonic examination of welds?
An A-scan display
217
What law can be used to calculate the angle of refraction within a metal for both longitudinal and shear waves?
Snell's Law
218
What must be done to evaluate discontinuities that are oriented at an angle to the entry surface so that the sound beam will strike the plane of the discontinuity at right angles?
Angulate the search unit
219
What type of ultrasonic examination uses wheel-type search units that eliminate the use of a tank?
Immersion testing.
220
When a C-scan recording is used to produce a permanent record of an ultrasonic test, the information displayed is typically the:
Discontinuity location and size (plan view).
221
When a vertical indication has reached the maximum signal height which can be displayed or viewed on the CRT of an ultrasonic instrument, the indication is said to have reached its:
Vertical level
222
When adjusting the flaw locating rule for a shear wave weld inspection, the zero point on the rule must coincide with the:
Sound beam exit point of the wedge
223
When an ultrasonic beam passes through the interface between two dissimilar materials at an angle, a new angle of sound travel takes place in the second material due to:
Refraction
224
When angle beam contact testing a test piece, increasing the incident angle until the second critical angle is reached results in:
Production of a surface wave
225
When conducting a contact ultrasonic test, the "hash" or irregular signals that appear in the CRT display of the area being inspected could be caused by:
Coarse grains in the structure.
226
When contact testing, if the ultrasonic instrument is set with an excessively high pulse repetition rate, which of the following may occur?
Ghost or "phantom" indications will appear on screen during scanning.
227
When examining materials for planar flaws oriented parallel to the part surface, what testing method is most often used?
Straight beam
228
When inspecting coarse-grained material, which of the following frequencies will generate a sound wave that will be most easily scattered by the grain structure?
10 MHz
229
When performing a surface wave test, indications may result from:
Surface discontinuities Oil on the surface Dirt on the surface All three of the above
230
When testing a part with a rough surface, it is generally advisable to use:
a lower frequency search unit and a more viscous couplant than is used on parts with a smooth surface.
231
When testing a plate, increasing the frequency of an ultrasonic longitudinal wave will result in:
No change in its velocity
232
When testing by the surface wave method, patches of oil or dirt on the surface may:
Cause both an attenuation of sound and indications on the screen.
233
When the incident angle is chosen to be between the first and second critical angles, the ultrasonic wave generated within the part will be:
Shear
234
When the incident angle is chosen to be between the first and second critical angles, the ultrasonic wave mode within the part will be a:
Shear wave
235
When the motion of the particles of a medium is parallel to the direction of propagation, the wave being transmitted is called a:
Longitudinal wave
236
When the motion of the particles of a medium is transverse to the direction of propagation, the wave being transmitted is called a:
Shear wave
237
When using focused transducers, non-symmetry in a propagated sound beam may be caused by:
Backing material variations Lens centering or misalignment Porosity in lenses All of the above
238
When using two separate search units (one a transmitter, the other a receiver), the most efficient combination would be:
A barium titanate transmitter and a lithium sulfate receiver.
239
Where does beam divergence occur?
Far field
240
Which best describes a typical display of a crack whose major surface is perpendicular to the ultrasonic beam?
A sharp indication
241
Which circuit coordinates operation of the entire ultrasonic instrument system?
Clock
242
Which circuit generates a burst of energy which is applied to the sending transducer?
Pulser
243
Which circuit triggers the pulser and sweep circuits in an A-scan display?
Clock
244
Which circuits electronically amplify return signals from the receiving transducer and often modify the signals into a form suitable for display?
Receiver-amplifier circuits
245
Which circuits modify the return signal from the receiving transducer into a form suitable for display on an oscilloscope or other output device?
Receiver-amplifier
246
Which component in an ultrasonic immersion system is used to adjust and maintain a known transducer angle?
A manipulator
247
Which is a plot of signal amplitude versus time?
An A-scan display
248
Which of the following can occur when an ultrasonic beam reaches the interface of two dissimilar materials?
Reflection Refraction Mode conversion All of the above
249
Which of the following controls the voltage supplied to the vertical deflection plates of the CRT in an A-scan UT setup?
Amplifier circuit
250
Which of the following frequencies will produce the shortest wavelength pulse?
25 megahertz
251
Which of the following frequencies would probably result in the greatest amount of attenuation losses?
10 megahertz.
252
Which of the following has the longest Fresnel zone?
1-1/2-inch diameter 2.0 MHz.
253
Which of the following is a reference reflector that is not dependent on beam angle
A side drilled hole which is parallel to the plate surface and perpendicular to the sound path
254
Which of the following is not an advantage of contact ultrasonic search units(probes) adapted with lucite shoes?
Decreases sensitivity.
255
Which of the following materials of the same alloy is most likely to produce the greatest amount of sound attenuation over a given distance?
A coarse grained casting
256
Which of the following may result in a long narrow rod if the beam divergence results in a reflection from a side of the test piece before the sound wave reaches the back surface?
Conversion from the longitudinal mode to shear mode.
257
Which of the following modes of vibration are quickly damped out when testing by the immersion method?
Surface waves
258
Which of the following scanning methods could be classified as an immersion type test?
Tank in which the search unit and test piece are immersed Squirter bubbler method in which the sound is transmitted in a column of flowing water Scanning with a wheel-type search unit with the transducer inside a liquid filled tire
259
Which of the following search units would contain the thickest crystal?
A 1 megahertz search unit.
260
Which of the following search units would contain the thinnest quartz crystal?
A 25-MHz search unit
261
Which of the following test frequencies would generally provide the best penetration in a 12-inch thick specimen of coarse- grained steel?
1.0 MHz
262
Which of the following would be considered application(s) of ultrasonic techniques?
Determination of a material's elastic modulus Study of a material's metallurgical structure Measurement of a material's thickness All of the above.
263
The angle at which 90 degree refraction of a longitudinal sound wave is reached is called:
The first critical angle.
