NDT Exam 1 Study Guide & Non-Destructive Testing Fundamentals
Revision Notes
Capillary Action - ✔✔The process of liquid penetrating or moving towards small cracks or
fixtures in objects
Discontinuity - ✔✔Weld profiles that deviate from standard and are undercut, overlap, or
excessive convexity.
Defect - ✔✔Any mistake or flaw in a weld that makes the weld useless
Viscosity - ✔✔The fluid's resistance to flow, or how fast the liquid flows into the defect
Surface Tension - ✔✔The cohesion forces in a liquid cause surface tension or the liquids ability
to stay on the surface of the part
Dwell time - ✔✔How long the liquid is in contact with the surface of the part
Hydrophilic Emulsifier - ✔✔METHOD D -A remover of liquid penetrant that uses mechanical or
chemical action where no diffusion takes place, the detergents mostly contain solvents and
surfactants
Lipophilic Emulsifier - ✔✔METHOD B -A remover of liquid penetrant that uses mechanical and
chemical action. While the mechanical action is working on the surface of the part to remove
the liquid while the chemical diffuser works to break down and remove the liquid penetrating
the part. Then excess is removed with water
Non-relevant Indication - ✔✔Visible remains from liquid testing that are not showing material
discontinuity but rather a mistake processing
Revision Notes
Capillary Action - ✔✔The process of liquid penetrating or moving towards small cracks or
fixtures in objects
Discontinuity - ✔✔Weld profiles that deviate from standard and are undercut, overlap, or
excessive convexity.
Defect - ✔✔Any mistake or flaw in a weld that makes the weld useless
Viscosity - ✔✔The fluid's resistance to flow, or how fast the liquid flows into the defect
Surface Tension - ✔✔The cohesion forces in a liquid cause surface tension or the liquids ability
to stay on the surface of the part
Dwell time - ✔✔How long the liquid is in contact with the surface of the part
Hydrophilic Emulsifier - ✔✔METHOD D -A remover of liquid penetrant that uses mechanical or
chemical action where no diffusion takes place, the detergents mostly contain solvents and
surfactants
Lipophilic Emulsifier - ✔✔METHOD B -A remover of liquid penetrant that uses mechanical and
chemical action. While the mechanical action is working on the surface of the part to remove
the liquid while the chemical diffuser works to break down and remove the liquid penetrating
the part. Then excess is removed with water
Non-relevant Indication - ✔✔Visible remains from liquid testing that are not showing material
discontinuity but rather a mistake processing
