NDT Nondestructive Testing Methods & Techniques 3

Question 1

What NDT method uses high-frequency sound waves transmitted through a couplant to detect internal flaws?

Accepted Answer

Ultrasonic testing

Answer

Ultrasonic testing (UT) transmits high-frequency sound waves (typically 1–10 MHz) through a liquid couplant into the material to detect reflections from internal discontinuities.

Question 2

During a hydrostatic pressure test, what is the primary hazard compared to a pneumatic pressure test?

Accepted Answer

Pneumatic tests are more dangerous because compressed gas stores significantly more energy than liquid

Answer

Pneumatic tests using compressed gas store far more elastic energy than hydrostatic tests using liquid; a catastrophic failure in a pneumatic test releases energy explosively, making it significantly more hazardous.

Question 3

In eddy current testing, what effect does a crack or void in a conductive material have on the eddy current flow?

Accepted Answer

It forces eddy currents to flow around the discontinuity, changing the impedance signal

Answer

Discontinuities interrupt the normal circular eddy current paths, forcing currents to reroute, which alters the coil impedance and produces a detectable signal change.

Question 4

Which document typically establishes the specific acceptance criteria that a boilermaker NDT inspector must apply when evaluating weld indications?

Accepted Answer

The applicable construction or inspection code (e.g., ASME Section VIII)

Answer

Acceptance criteria for weld indications in pressure vessels are defined by the governing construction or inspection code, such as ASME Boiler and Pressure Vessel Code Section VIII.

Question 5

What is 'signal-to-noise ratio' in the context of ultrasonic testing?

Accepted Answer

The ratio of the flaw signal amplitude to the background noise level

Answer

Signal-to-noise ratio (SNR) compares the amplitude of the relevant flaw indication to the background noise; a high SNR makes it easier to distinguish real defects from material noise.

(NDT) Boilermaker Nondestructive Testing Certification Practice Test

(NDT) Boilermaker Nondestructive Testing Certification Practice Test

NDT Nondestructive Testing Methods & Techniques 3