Chapter Eleven Exam Flashcards
Can a shear or transverse wave travel in water or oil?
No due to lack of atomic attraction
What is the force that causes the phenomenon called piezoelectric effect? (Multiple Choice)
voltage
Unique properties that make sound propagation in solids possible are: (Multiple Choice)
ductility, hardness and shape
The wavelength is the distance:
Between crests of thee waves
The frequency of the ultrasonic wave:
Depends on transducer selected
An ultrasonic beam changes angle or refracts when it travels from a plastic probe into a steel specimen because:
The wave velocity is different from steel to plastic.
The change in direction of an incident sound wave below the surface is know as:
Refraction
What factors are involved in energy attenuation of the wave through a material?
Beam spread, absorption and scattering.
Dampening material forms part of the cross-section of a typical probe. Why?
Control vibration of the crystal
Which of the following is true regarding the detectable reflector (defect) and wavelength?
reflector that may be detected is generally in order of half the wavelength
Transducers used in ultrasonic testing convert electrical energy into
mechanical vibrations
Velocity is one important part of the universal wave equation, and if that is true, can one velocity be used for all types of materials?
Different velocity is required for all materials.
Parts are sometimes immersed in water in order to examine them. The probe’s distance from the water surface to the part needs to be removed from the display using:
Delay
In what unit is the gain control (or attenuator) marked?
decibels
Which type of display gives a cross-sectional view showing the length and depth of discontinuities?
B scan
The ASME approach for evaluation of discontinuities are:
Amplitude size and type.
What is the common method for measuring the length of a defect?
Measure the distance on the surface between two peaks where the amplitude drops to 6dB below the max value.
Planar discontinuities include:
Cracks
Which standard defines the parameters that should be reported during the UT inspection procedure?
ASTM E164
What is the correct procedure to calibrate the screen trace for distance with a normal probe and an IIW block?
Reflectbeam from curved end with the probe at a fixed distance then adjust screen trace accordingly. WRONG. Maybe place probe and maximum and read off scale.
Rejection of discontinuities are based on two general approaches:
Quality control and fitness for purpose criterion
The indication rating (dB), that is the height and low levels of amplitude signals, is a measure of defect:
length
Difficulties with UT can arise when welds have backing bars due to reflections coming from:
Weld root, backing bar, and multiple internal reflections
The type of transducer that allows access to a flat inspection surface to examine a weld is the:
Normal wave transducer
