NDT - Non-Destructive Testing Discontinuity Interpretation and Evaluation Questions and Answers

Question 1

An NDT technician evaluates a radiograph of a multi-pass weld and observes several dark, irregularly shaped indications with well-defined outlines, located between weld passes.
Which type of discontinuity is most likely being observed?

Accepted Answer

Slag Inclusions

Answer

Incomplete Penetration

Answer

Porosity

Answer

Longitudinal Cracking

Question 2

In the context of Nondestructive Testing, what is the fundamental distinction between a "discontinuity" and a "defect"?

Accepted Answer

A "discontinuity" is an interruption in the material, while a "defect" is a discontinuity that does not meet specified acceptance criteria.

Answer

A discontinuity is always subsurface, while a defect is always surface-breaking.

Answer

A "defect" is a discontinuity that has been proven to be three-dimensional.

Answer

A "discontinuity" refers to metallurgical anomalies, while a "defect" refers to mechanical damage.

Question 3

During a shear wave ultrasonic inspection of a weld, the technician observes a sharp, high-amplitude signal that moves across the A-scan display as the transducer is moved parallel to the weld. The signal's amplitude changes significantly with slight angulation of the transducer. This is most characteristic of:

Accepted Answer

A planar discontinuity, such as a crack or lack of fusion.

Answer

A cluster of porosity.

Answer

A large slag inclusion.

Answer

Geometric reflections from the weld crown.

Question 4

When evaluating a known discontinuity, which of the following characteristics is generally considered the MOST critical in determining its potential to cause a structural failure under tensile stress?

Accepted Answer

Its sharp, narrow tip and orientation perpendicular to the primary stress.

Answer

Its overall volume.

Answer

Its location deep within the material, far from the surface.

Answer

Its rounded, spherical shape.

Question 5

An inspector performs a liquid penetrant test on a new aluminum casting. After applying the developer, a series of very fine, intermittent linear indications appear. Upon closer visual examination, the inspector notes that these indications perfectly align with the machining marks from a previous manufacturing step. How should these indications be classified?

Accepted Answer

Non-relevant indications.

Answer

Relevant, rejectable cracking.

Answer

False indications due to improper cleaning.

Answer

Relevant, acceptable porosity.

Question 6

An NDT Level II inspector identifies and measures a relevant indication that exceeds the maximum allowable length specified in the applicable acceptance standard. The final step in the evaluation process is to:

Accepted Answer

report the indication as "unacceptable" or "rejectable."

Answer

recommend the part for immediate repair without further documentation.

Answer

classify the indication as a "severe discontinuity."

Answer

request a second opinion from another Level II inspector before making a decision.