NDT Techniques - II (UT) — Winter 2025

Define the basic principle of sound propagation and briefly list the types of sounds with their frequencies.

What is a Piezoelectric Material? State its primary role in an ultrasonic transducer.

Differentiate between the Longitudinal wave and Transverse (Shear) wave sound propagation modes in solids, with respect to particle motion with figure. State the principle of ultrasonic testing.

Mention any three advantages of Ultrasonic Testing over other NDT methods.

Define the wavelength and frequency. Find the wavelength having the frequency MHz and velocity is 6000 m/s.

What do you mean by attenuation of sound waves? How sound waves are attenuated, and what is the impact of attenuation on ultrasonic testing?

Acylindrical rod is tested using immersion ultrasonic testing. Describe setup, advantages, and inspection steps.

What is the basic working principle of Ultrasonic Testing?

What is the role of the transducer in UT? What are types of transducers used in UT?

The acoustic impedance of air is 0.004 X 105 kg/m2 s, water is 1.5 X 105 kg/m2 s, and steel is about 46.5 X 105 kg/m2 s. Explain how this impedance differences affect the reflection and transmission of ultrasonic waves at the air to steel and water to steel interfaces.

An ultrasonic pulse takes 12 microseconds to travel to a defect and return. If sound velocity is 6000 m/s, find the depth of the defect.

A 50 mm thick steel plate is tested for internal flaws using pulse-echo UT. Explain how reflection signals help locate defects with depth calculation.

Awelded steel plate is inspected using a shear wave transducer. Explain the full procedure for detecting side-wall cracks using angle-beam inspection. Page 1 of

Name the types of calibration clocks used in UT.

What is the critical angle in UT? How many critical angles are there in UT to carry inspection by oblique incident? Write angles of them.

Explain the pulse-echo technique to carry inspection on a steel plate having 100 mm thickness. Explain the method of calibration for normal incident on calibration block..

What parameters are responsible for the selection of probe frequency?

Match the probe frequency for particular material. Frequency of Sr. No. Materials Probe 1 4 - 6 MHz Concrete 2 5 - 6 MHz Aluminium Martensitic Stainless 3 0 - 1 MHz Steel Copper and Copper 4 2 MHz Alloys

Show the trigonometric calculation to find the defect in the weld sample by skip distance and surface distance by angle probe inspection.

What is the thumb rule to characterize the defect using UT?

Name four defects that can be characterized by UT.

Describe the A, B, and Cscan presentation of UT.

What is the principle of immersion testing? Write the advantages and limitation of test.

Discuss the principle, advantages and limitations of Acoustic Emission Testing (AET).

With neat sketch, describe the normal, TR and angle probe construction. Page 2 of