NDT Techniques - I (VI, LPT, MPT) — Summer 2025

What is the scope of non destructive testing in 21st century?

List the NDT methods with their prime importance in the industry.

Define the terms defect and discontinuity. With neat sketch illustrate the welding defects and write any remedies for any two defects.

What are the possible reasons to reject the product? By which means evaluator/inspector decides that whether component having non- conformity is acceptable or not?

What are the visual aids to be used for inspecting component by VT?

Which visual aid is used to inspect inside edge of steel pipe? Explain about its function and working principle with neat sketch.

What are the types of measuring and transferring instruments and welding gauges are used in visual testing? Write the least count of vernier caliper and micrometer screw gauge.

Define leak and leak rate.

Find the leak rate for a football with the given data: Diameter of football is 0.22 m, pressure of the football (Internal pressure) = 1900 mbar. The football is flat after 1 month (internal pressure = external ∆p pressure). External pressure is 1000 mbar. Formula (Q = V ) ∆t Where ∆p is the difference between the internal pressure and the external pressure, ∆t is the time, and Vis the volume of the container.

With neat sketch explain the helium leak detector.

List the technological and physical characteristics of penetrant.

What are the types of penetrant? Explain the sensitivity difference between both the penetrants.

Explain the procedural steps to carry liquid penetrant testing.

What is the principle of liquid penetrant testing?

Acomponent having fatigue crack, the component is made up of aluminium. Which method is suitable out of LPT and MPT?

List the excess penetrant removable methods. Explain any two in details. OR1

Draw the hysteresis loop. What is the significance in MPT?

What happen if the component is not to be demagnetized before using in service?

To generate the magnetism in the component, which law has to obey? By using it, explain the circular and longitudinal magnetization.

What is the basic principle of magnetic particle testing?

Explain the yoke and prod method of MPT.

What is fluorescent MPT and how does it differ from visible MPT? List applications where fluorescent MPT is preferred.

List the equipment used in magnetic particle inspection.

Differentiate between diamagnetic, paramagnetic and ferromagnetic materials.

Discuss the common applications and limitations of MPT.