AWS Welding Defects & Quality Control

Question 1

Which NDE method is best suited for detecting surface and near-surface cracks in ferromagnetic welds?

Accepted Answer

Magnetic particle testing (MT)

Answer

Magnetic particle testing (MT) is the most sensitive and practical method for detecting surface and near-surface (up to ~1/4 inch) cracks in ferromagnetic materials like carbon and low-alloy steel welds.

Question 2

Liquid penetrant testing (PT) is applicable to:

Accepted Answer

Any material — ferromagnetic and non-ferromagnetic alike

Answer

Liquid penetrant testing works on any non-porous material regardless of magnetic properties — it detects surface-open discontinuities in metals, ceramics, and plastics alike.

Question 3

Lack of fusion (LOF) in a groove weld is best detected by:

Accepted Answer

Ultrasonic testing (UT)

Answer

Ultrasonic testing (UT) is most effective for detecting lack of fusion because planar defects (LOF, cracks) perpendicular to the ultrasonic beam reflect strong signals, while RT often misses planar defects oriented parallel to the X-ray beam.

Question 4

Lamellar tearing in welded joints occurs:

Accepted Answer

In the base metal below the HAZ in low-ductility, through-thickness directions of rolled plate

Answer

Lamellar tearing occurs in the base metal below and parallel to the fusion line in rolled plate with low through-thickness ductility, caused by through-thickness contraction stresses during weld cooling.

Question 5

What does 'Charpy V-notch' (CVN) impact testing measure in weld procedure qualification?

Accepted Answer

The fracture toughness (energy absorbed during fracture) at specified temperatures

Answer

CVN testing measures the energy (in ft-lbs or Joules) absorbed by a notched specimen during fracture impact, characterizing the weld metal's fracture toughness and ductile-to-brittle transition temperature.

AWS Practice Test

AWS Practice Test

AWS Welding Defects & Quality Control