456A Weld Quality Inspection, Testing & Occupational Safety

Question 1

What is the primary difference between a 'destructive test' and a 'non-destructive test' (NDT) in weld inspection?

Accepted Answer

Destructive tests destroy the test coupon/weld to measure properties; NDT examines the weld without destroying it, allowing the tested component to remain in service

Answer

Destructive tests are performed on production welds; NDT is only for procedure qualification

Answer

NDT detects surface defects only; destructive tests detect internal defects

Answer

Destructive testing is optional; NDT is always mandatory on production welds

Question 2

What does 'visual inspection' (VT) detect in welds and what tools are used per CSA W59?

Accepted Answer

Surface discontinuities including cracks, undercut, overlap, surface porosity, crater fill, weld profile/size, and weld length; tools include weld gauges, magnifying lens, fillet gauges, and adequate lighting

Answer

Only weld size and geometry; no discontinuities can be detected visually

Answer

Internal discontinuities such as lack of fusion and internal porosity

Answer

Visual inspection is not an accepted inspection method under CSA W59

Question 3

What is 'radiographic testing' (RT) of welds and what type of defects is it most sensitive to?

Accepted Answer

X-ray or gamma-ray imaging of the weld; most sensitive to volumetric discontinuities — porosity, slag inclusions, burn-through, incomplete penetration

Answer

Ultrasonic vibration of the weld metal; most sensitive to planar defects

Answer

Magnetic field application to detect surface-breaking cracks only

Answer

Penetrant dye applied to the surface; reveals surface-breaking discontinuities

Question 4

What is 'ultrasonic testing' (UT) and what type of weld defects is it best suited to detect compared to RT?

Accepted Answer

Uses high-frequency sound waves; best suited to planar defects (cracks, LOF, LOP) that are poorly detected by RT due to orientation

Answer

Uses electromagnetic induction to detect surface defects only

Answer

Uses visible light refraction to measure weld geometry from the surface

Answer

Uses acoustic emission detection during weld solidification to predict internal defects

Question 5

What is 'magnetic particle testing' (MT) and on which base metals can it be used?

Accepted Answer

Uses magnetic fields and iron particle indicators to reveal surface and near-surface discontinuities; can only be used on ferromagnetic materials (carbon steel, low-alloy steel)

Answer

Uses high-powered magnets to attract subsurface defects to the surface for visual inspection

Answer

Can be used on all metals including austenitic stainless steel and aluminum

Answer

Detects internal voids using magnetic resonance imaging technology

Question 6

What is 'dye penetrant testing' (PT) and what is the correct sequence of steps?

Accepted Answer

Apply penetrant → dwell → remove excess → apply developer → inspect → post-clean; detects surface-breaking discontinuities in any non-porous material

Answer

Apply developer → apply penetrant → inspect → remove; works on all metals and non-metals

Answer

Apply penetrant permanently and inspect under UV light immediately; used for subsurface defects

Answer

Apply magnetic developer → wait → read with ultraviolet lamp; used for ferromagnetic metals only