CWI NDE Methods and Symbols 4

Question 1

In liquid penetrant testing, what is the minimum recommended dwell time for most standard penetrants on steel weldments per ASME standards?

Accepted Answer

10 minutes

Answer

ASME Section V typically specifies a minimum penetrant dwell time of 10 minutes for standard penetrants on steel to allow adequate capillary action into discontinuities.

Question 2

What is the primary limitation of liquid penetrant testing compared to other NDE methods?

Accepted Answer

It can only detect surface-open discontinuities

Answer

PT relies on penetrant entering open discontinuities at the surface, so it cannot detect sub-surface or embedded defects.

Question 3

In RT, the wire-type IQI is placed on the source side of the part. If the required 2T wire is visible on the radiograph, what does this confirm?

Accepted Answer

The technique has sensitivity sufficient to detect a flaw equivalent to 2% of the material thickness

Answer

The visible 2T wire confirms the radiographic technique sensitivity meets code requirements, typically 2% of material thickness for most codes.

Question 4

Which scanning pattern in ultrasonic testing involves moving the transducer perpendicular to the weld axis while indexing along the weld?

Accepted Answer

Raster scan

Answer

A raster scan moves the probe perpendicular to the weld in parallel passes, systematically indexing along the weld length to provide full volumetric coverage.

Question 5

What type of radiation source is commonly used in industrial radiography for field inspection of thick steel welds where X-ray machines are impractical?

Accepted Answer

Iridium-192 (Ir-192)

Answer

Ir-192 is the most widely used gamma-ray isotope for field radiography of steel welds due to its appropriate energy level, portability, and practical half-life of 73.8 days.

CWI Practice Test

CWI Practice Test

CWI NDE Methods and Symbols 4