1
Q
What is Penetrant Testing (PT)?
A
A non-destructive testing (NDT) method to detect surface-breaking defects in non-porous materials
Relies on capillary action—penetrant liquid seeps into surface flaws and is drawn out to reveal defects.
2
Q
List the steps involved in Penetrant Testing.
A
- Pre-cleaning
- Application of Penetrant
- Dwell Time
- Excess Removal
- Developer Application
- Inspection
- Post-cleaning
Each step is crucial for accurate defect detection.
3
Q
What are the advantages of Penetrant Testing?
A
- Simple
- Cost-effective
- Detects very fine cracks
However, it has limitations such as only detecting surface defects.
4
Q
What is Cohesion in the context of Penetrant Testing?
A
The intermolecular attraction between like molecules
High cohesion in penetrant can reduce its ability to spread and enter fine cracks.
5
Q
What is Adhesion in Penetrant Testing?
A
The attraction between unlike molecules
Good adhesion ensures penetrant wets the surface and enters defects.
6
Q
What does Capillary Action depend on in Penetrant Testing?
A
- Low surface tension
- High wetting ability
These properties are optimized in penetrant liquids for maximum flaw detection.
7
Q
What is Type I penetrant?
A
Fluorescent Penetrant
Requires UV light for inspection and has higher sensitivity than Type II.
8
Q
What is Type II penetrant?
A
Visible Dye Penetrant
Inspected under white light and suitable for general industrial use.
9
Q
What is an Emulsifier?
A
A substance that combines with the penetrant and converts it into an emulsion
Allows the penetrant to be rinsed away with water after inspection.
10
Q
What are the types of emulsifiers?
A
- Lipophilic (Method B)
- Hydrophilic (Method D)
Each type has different applications and methods of action.
11
Q
What is the purpose of a Lipophilic Emulsifier?
A
Oil-based emulsifier applied directly to the surface
Works by dissolving into the penetrant and making it water-washable.
12
Q
What is the purpose of a Hydrophilic Emulsifier?
A
Water-based emulsifier that uses surfactants to break down penetrant
Allows for easier rinsing and is often used in aerospace.
13
Q
What is a Solvent-Removable Penetrant?
A
Penetrant removed using a dry cloth followed by a solvent-dampened cloth
Used in field inspections where water is not available.
14
Q
What are Solvent Cleaners used for?
A
Remove excess penetrant from the surface in solvent-removable systems
Must be non-corrosive and leave no residue.
15
Q
What is the purpose of Developers in Penetrant Testing?
A
Draw penetrant out of defects and provide a contrasting background
Enhances visibility of indications.
16
Q
What are the types of developers?
A
- Dry Powder
- Water-Suspendable / Water-Soluble
- Non-Aqueous Wet Developer (NAWD)
Each type serves different applications and conditions.
17
Q
What is capillary action in the context of NDT Penetrant testing?
A
The ability of a liquid to flow in narrow spaces without the assistance of external forces
Capillary action is crucial for the effectiveness of penetrant testing as it allows the penetrant to enter small cracks and voids.
18
Q
What is the function of wetting in NDT Penetrant testing?
A
To ensure that the penetrant adheres to the surface and fills any surface-breaking defects
Proper wetting is essential for accurate detection of flaws during the testing process.
19
Q
Capillary action requires:
* is unrelated to the adhesive properties
* requires a high contact angle
* good wetting ability to work properly
* low wetting ability to work properly
A
Answer: good wetting ability to work properly. Explanation: Penetrant is drawn into surface-breaking flaws by capillary action. This requires strong adhesion (wetting) to the surface and a low contact angle, which allows the liquid to spread and enter tight openings.
20
Q
If water is left on the surface of a part to be liquid penetrant examined, it:
* would be unacceptable for any liquid penetrant exam
* would be acceptable for water washable and both post emulsifiable penetrant exams
* would be unacceptable for solvent removable process only
* would be acceptable for water washable process only
A
Answer: would be unacceptable for any liquid penetrant exam. Explanation: Residual water prevents proper wetting and can block penetrant entry. All penetrant processes require a clean, dry surface prior to application.
21
Q
The best technique for cleaning a rough sand cast surface would be:
* the post emulsified process
* the leak through process
* the water washable process
* the solvent removable process
A
Answer: the post emulsified process
Explanation: For very rough surfaces, post-emulsifiable penetrant allows controlled removal of excess penetrant, reducing background on porous or textured cast surfaces.
22
Q
The wavelength of the ultraviolet light allowed to pass through a black light filter are:
* from 550 to 895 nm
* from 200 nm to 800 nm
* centered on 550 nm
* centered on 365 nm
A
Answer: centered on 365 nm
Explanation: Standard UV-A inspection lamps for fluorescent penetrant testing emit light peaking near 365 nm (UV-A band).
23
Q
Interpretation refers to:
* the process of determining what caused an indication
* the process of determining whether the indication is acceptable or unacceptable
* the process of developing the test
* something only level III technicians can do
A
Answer: the process of determining what caused an indication
Explanation: Interpretation identifies the nature and source of an indication. Evaluation is the step that compares it against acceptance criteria.
24
Q
When we are talking about water washable or post emulsifiable processes we are discussing:
* a developing process
* a method of applying the dye penetrant to the surface
* a pre-cleaning process
* a method of removing excess dye penetrant
A
Answer: a method of removing excess dye penetrant
Explanation: Water-washable and post-emulsifiable classify penetrants by how excess penetrant is removed prior to developer application.
25
Liquid penetrant testing will detect:
* only flaws open to the surface
* only flaws that are wholly sub-surface
* only cracks
* all flaws
Answer: only flaws open to the surface
Explanation: Penetrant can only enter discontinuities that break the surface; it cannot detect entirely subsurface flaws.
26
Which of the following is a form of developer?
* High penetration developer
* Dry soluble developer
* Non-aqueous wet developer
* Non-aqueous dry developer
Answer: Non-aqueous wet developer
Explanation: Standard developer types include dry powder, water-soluble, water-suspendable, and non-aqueous wet. 'Dry soluble' and 'non-aqueous dry' are not standard terms.
27
The least sensitive penetrant exam would be:
* the solvent removable process
* the lipophilic post emulsifiable process
* the water washable process
* the hydrophilic removable process
Answer: the solvent removable process
Explanation: Solvent-removable penetrant is typically used for small localized areas and tends to provide the lowest overall sensitivity compared to water-washable and post-emulsifiable processes.
The solvent removable penetrant process is generally considered the least sensitive because:
- Lower Penetrant Retention
Solvent removal tends to clean the surface aggressively, which can also remove penetrant from shallow or fine flaws. This reduces the chance of detecting very small discontinuities.
- Limited Developer Interaction
Solvent-based systems often rely on non-aqueous wet developers, which do not provide as strong a contrast or indication buildup as systems using water-based developers
28
If a part to be examined by liquid penetrant has scale on it which of the choices below would be acceptable for preparing the surface?
* Ultrasonic cleaner
* Acid etching then rinse with water and clean with a solvent cleaner
* Solvent cleaning
* Paint remover then clean with a solvent cleaner
Answer: Acid etching then rinse with water and clean with a solvent cleaner
Explanation: Tightly adherent oxides or scale must be removed (e.g., by chemical etch), followed by thorough rinsing and final solvent cleaning to ensure the surface is clean and dry for penetrant.
29
Which of the following surface preparations are unacceptable prior to performing a liquid penetrant examination?
* Hand wire brushing
* Acid etch with water rinse
* Solvent cleaning
* Shot blasting
Answer: Shot blasting
Explanation: Shot peening/blasting can smear metal and close small surface openings, masking discontinuities and making penetrant ineffective.
30
If a procedure defined the area to be examined with liquid penetrant as the weld and 1/2" adjacent base material, the minimum area to be pre-cleaned would be:
* the weld only
* the weld and 3" each side of the weld
* the weld and 1 1/2" on each side of the weld
* the weld and 1/2" of the base material on each side of the weld
Answer: the weld and 1/2" of the base material on each side of the weld
Explanation: Pre-cleaning must cover, at minimum, the full area to be examined so penetrant can properly wet and reveal indications throughout the specified region.
31
One of the most important steps needed to obtain a valid liquid penetrant exam would be:
* the technique used to removing the excess penetrant from the surface
* the application of a wet developer
* the pre-cleaning of the surface prior to the penetrant exam
* the method of applying a penetrant to the surface
Answer: the pre-cleaning of the surface prior to the penetrant exam
Explanation: Cleanliness is critical; contaminants such as oil, paint, scale, and water inhibit wetting and capillary action, leading to false or missed indications.
32
The purpose of an emulsifier is to:
* allow for higher temperature inspections
* render the penetrant on the surface to be water washable
* enhance the capillary action
* penetrate the part to remove the dye
Answer: render the penetrant on the surface to be water washable
Explanation: In post-emulsifiable systems, the penetrant is initially water-insoluble. The emulsifier chemically modifies it so the excess penetrant can be washed off with water.
33
Which process has a pre-rinse step?
* Water washable
* Post emulsifiable using a hydrophilic emulsifier
* Solvent removable
* Post emulsifiable using a lipophilic emulsifier
Answer: Post emulsifiable using a hydrophilic emulsifier
Explanation: Hydrophilic (detergent-type) emulsifiers require a water pre-rinse to remove loosely held penetrant before applying the emulsifier, then a final rinse. Lipophilic emulsifiers are applied without a pre-rinse.
Hydrophilic Emulsifier:
Water-loving
Works by making penetrant water-soluble for rinsing
Requires water spray and precise timing
Used for high-sensitivity inspections
Lipophilic Emulsifier:
Oil-loving
Dissolves into penetrant before rinse
Less aggressive, easier to control
Used for medium-sensitivity inspections
34
What is the purpose of the **developer** in liquid penetrant NDT testing?
To draw penetrant out of surface flaws and provide a contrasting background
## Footnote
The developer is applied after excess penetrant is removed.
35
Name the **three main types of developers** used in liquid penetrant NDT testing.
* Dry Powder Developer
* Wet Developer (Non-Aqueous)
* Wet Developer (Aqueous)
## Footnote
Each type of developer has specific applications and characteristics.
36
What is a **Dry Powder Developer**?
Fine absorbent powder applied to dry surfaces
## Footnote
Commonly used in fluorescent penetrant inspections.
37
What characterizes a **Wet Developer (Non-Aqueous)**?
Suspended in a volatile solvent and sprayed onto the part
## Footnote
Often used for field or localized applications.
38
What does a **Wet Developer (Aqueous)** include?
Water-soluble and water-suspendable forms
## Footnote
Applied by immersion or spray, then dried before inspection.
39
Dry developers work best in situations where **fluorescent penetrant inspections** are performed in a _______.
controlled environment (darkroom)
## Footnote
Dry powder provides a strong contrast under UV light.
40
What must be ensured about parts when using **dry developers** after penetrant removal?
Parts are completely dry
## Footnote
Any residual moisture will cause clumping and poor coverage.
41
Dry developers are suitable for **smooth or slightly rough surfaces** where the powder can _______.
adhere evenly
## Footnote
This ensures effective coverage during inspections.
42
Dry developers are commonly used for **small to medium-sized components** that can be easily _______.
handled and dusted without contamination
## Footnote
This facilitates effective application of the developer.
43
Dry developers are commonly used in **Method A** and **Method D** penetrant systems for _______.
high-sensitivity inspections
## Footnote
Method A is water-washable, and Method D is post-emulsifiable hydrophilic.
44
The ability of a liquid penetrant to penetrate into flaws is solely
dependent on:
- Viscosity only
- Surface tension only
- A proper balance of the properties of the penetrant materials
- Temperature only
Answer: A proper balance of the properties of the penetrant materials
Explanation: Penetrant effectiveness depends on a combination of properties like viscosity, surface
tension, and wetting ability.
45
The maximum temperature permitted in a dryer oven is:
- 125°F
- 160°F
- 200°F
- 180°F
Answer: 160°F
Explanation: Higher temperatures can degrade penetrant or developer properties, affecting test
reliability.
46
If a test surface is below 50°F, the penetrant dwell time shall:
- Decrease due to low viscosity
- Increase due to increased viscosity
- Remain unchanged
- Be eliminated
Answer: Increase due to increased viscosity
Explanation: At lower temperatures, penetrant becomes more viscous, slowing its ability to enter flaws.
Longer dwell time compensates for this.
47
Which developer should NOT be used with visible penetrant
systems?
- Dry powder developer
- Non-aqueous wet developer
- Aqueous wet soluble developer
- None of the above
Answer: Aqueous wet soluble developer
Explanation: Visible penetrant systems typically use dry or non-aqueous wet developers. Aqueous wet
soluble developers are incompatible.
48
The primary contaminant found in water washable penetrant
would be:
- Oil
- Water
- Dust
- Solvent
Answer: Water
Explanation: Since the system uses water for removal, water contamination in penetrant is common
and can affect sensitivity.
49
Emulsifiers shall be applied by:
- Brushing, spraying, or dipping
- Pouring only
- Immersion only
- None of the above
Answer: Brushing, spraying, or dipping
Explanation: These methods ensure uniform coverage without damaging the part surface.
50
Rough surfaces would be best developed with:
- Dry powder developer
- Non-aqueous wet developer
- Aqueous wet developer
- None of the above
Answer: Non-aqueous wet developer
Explanation: Non-aqueous wet developers provide better coverage on irregular surfaces compared to
dry or aqueous types.
51
The final evaluation of the exam is based on:
- Color of indication
- Size of the bleed-out indication
- Shape of the part
- Temperature of the part
Answer: Size of the bleed-out indication
Explanation: Indication size reflects flaw size and is the primary criterion for acceptance or rejection.
52
The most sensitive penetrant system would be:
- Visible dye penetrant
- Water washable fluorescent penetrant
- Post-emulsified fluorescent penetrant system
- None of the above
Answer: Post-emulsified fluorescent penetrant system
Explanation: Fluorescent penetrants are more sensitive than visible dyes, and post-emulsification
enhances flaw detection.
53
The term dwell refers to:
- Time to dry developer
- Any time period required to pass before performing another step
- Time to heat part
- None of the above
Answer: Any time period required to pass before performing another step
Explanation: Dwell time is the interval during which penetrant or developer remains on the part to allow
proper action.
54
The chemistry of penetrant materials must be controlled for
stainless, nickel, and titanium alloys because:
- They must be limited to 1% by weight for halogens and sulfur
- They must contain no oxygen
- They must be magnetic
- None of the above
Answer: They must be limited to 1% by weight for halogens and sulfur
Explanation: Excess halogens or sulfur can cause corrosion or cracking in these alloys.
55
When removing excess penetrant, the main concern is:
- Cleaning the penetrant from the broad, shallow flaws
- Removing all penetrant
- Drying the part
- None of the above
Answer: Cleaning the penetrant from the broad, shallow flaws
Explanation: Improper removal can mask indications or cause false positives.
56
The temperature of the parts and materials may not exceed:
- 125°F
- 160°F
- 180°F
- 200°F
Answer: 125°F
Explanation: Higher temperatures can alter penetrant properties and affect test accuracy.
57
The most effective system to examine threaded parts would be:
- Visible dye penetrant
- Water washable penetrant
- Post-emulsifiable lipophilic fluorescent penetrant
- None of the above
Answer: Water washable system
58
A disadvantage of the water washable system is:
- It is the least sensitive of the systems
- It is the most expensive
- It requires special lighting
- None of the above
Answer: It is the least sensitive of the systems
Explanation: Water washable systems are convenient but generally less sensitive than
post-emulsifiable systems.
59
Which of the following developers should not be used with water washable penetrants?
-Dry developer
- Aqueos wet suspensible developers
- Aqueos wet soluble developers
- Non-aqueous wet developers
Aqueous wet soluble developers
60
An aluminum cracked block is used to
* verify the smallest flaw that may be detected
* check the concentration of the emulsifier
* compare test conditions such as temperatures or materials
* verify the water content of the liquid penetrant held in open tanks
Answer: compare test conditions such as temperatures or materials
Explanation: The cracked block simulates real flaws, allowing two different methods/conditions to be compared.
61
A 'TAM' panel is required to verify
* concentration of emulsifier
* developer contamination
* the quality of penetrant systems held in open tanks
* the amount of contamination in a penetrant tank
Answer: the quality of penetrant systems held in open tanks
Explanation: TAM panels provide a standardized way to check penetrant performance over time.
62
The amount of visible (white) light permitted in a black-light viewing area is
* none
* 2 uW/cm2
* 2 foot-candles (fc)
* 100 foot-candles (fc)
Answer: 2 foot-candles (fc)
Explanation: Excessive white light can mask fluorescent indications, so limits are set for accuracy.
63
All parts should be post cleaned
* only when they will require painting
* at all times because of the potential for corrosion
* unless they are going to be welded later
* only when working on aerospace products
Answer: at all times because of the potential for corrosion
Explanation: Residual penetrant can cause corrosion or interfere with subsequent processes.
64
The meniscus test is
* determines the viscosity of the penetrant
* is performed by the manufacturer and determines the brightness and dye concentration
* performed on developers to verify concentration
* performed by the manufacturer's customer
Answer: is performed by the manufacturer and determines the brightness and dye concentration
Explanation: This test ensures the penetrant meets brightness and dye standards for detection.
65
Evaluation would be
* determining if the part is suitable for penetrant examination
* waiting for the developer to develop indications
* determining if the indication meets the acceptance criteria
* determining what caused the indication
Answer: determining if the indication meets the acceptance criteria
Explanation: Evaluation compares indications against standards to decide part acceptability.
66
A black light verification must be done daily and be
* a minimum of 800 uW/cm2
* a minimum of 100 foot-candles (fc)
* a minimum of 75 foot-candles (fc)
* a minimum of 1000 uW/cm2a
Answer: a minimum of 1,000 uW/cm2
Explanation: Adequate UV intensity is critical for fluorescent penetrant visibility.
67
False indications are
* required to be evaluated
* usually there by design
* usually unacceptable
* caused by poor technique
Answer: caused by poor technique
Explanation: Improper cleaning or application can create misleading indications.
68
The concentration of a hydrophilic emulsifier should be verified
* with a hydrometer
* with a comptometer
* with a refractometer
* with a centrifuge
Answer: with a refractometer
Explanation: Refractometers measure concentration accurately to maintain process control.
69
Which of the following developers do not normally require a quality control check periodically?
* Wet aqueous soluble developer
* Dry developer
* Wet aqueous suspendible developer
* Non-aqueous wet developer
Answer: Dry developer or wet Non-Aqueous wet developer (in can)
Explanation: Dry developers are less prone to contamination compared to wet types.
70
Light meters and pressure gages must be calibrated every
* month
* three months
* year
* six months
Answer: six months
Explanation: Regular calibration ensures accurate readings for compliance and safety.
71
An indication around a riveted joint would be considered
* unacceptable
* relevant
* false
* nonrelevant
Answer: nonrelevant
Explanation: Such indications often result from geometry rather than actual flaws.
72
True/False - A defect is any discontinuity that is judged harmful to the products end use and is determined by the acceptance criteria given in the code, specification, or procedure to be unacceptable.
True
73
False indications are the same as non-relevant indications?
False Indications
Definition: Indications that appear during inspection but do not correspond to any actual discontinuity or defect.
Cause: Usually due to poor technique, contamination, improper cleaning, or excessive penetrant left on the surface.
Example: Smearing of penetrant during removal creates a line that looks like a crack but isn’t.
Non-Relevant Indications
Definition: Indications that are real penetrant responses, but they occur because of part geometry or design features—not because of a defect.
Cause: Surface conditions like rivets, threads, keyways, or sharp corners that trap penetrant.
74
Difference between linear and rounded discontinuity?
Linear discontinuity has an aspect ratio of 3:1 or greater. Must be defined by code.
75
What are the three categories of discontinuities?
Inherent, Processing (primary & secondary), and Service
76
What are primary processing discontinuities?
Forging, drawing, or extruding
77
What are secondary processing discontinuities?
Machining, welding, bending
78
What are the three most common ingot discontinuities?
Piping, Porosity (gas), non-metallic inclusions (oxides)
79
Primary processing discontinuities for Plate
Laminations
Description: Internal separations or layers within the plate, often parallel to the surface.
Cause: Entrapped oxides, scale, or inclusions during rolling that prevent full bonding.
Appearance: Subsurface defect, usually detected by ultrasonic testing.
Impact: Reduces structural integrity and can lead to crack propagation under stress.
Scabs
Description: Irregular patches of metal adhering to the surface, often with rough edges.
Cause: Oxide scale or metal splinters pressed into the surface during rolling or incomplete removal of surface defects.
Appearance: Visible surface defect, sometimes raised or flaky.
Impact: Can interfere with coatings, welding, and may hide deeper flaws.
Key Difference:
Lamination = Internal defect (layered separation)
Scab = Surface defect (adhered patch)
80
Primary processing discontinuities for Bar stock
1. Seams
Description: Long, narrow surface discontinuities running along the length of the bar.
Cause: Rolled-in cracks or folds during hot rolling.
Impact: Can propagate under stress, especially during machining or service.
2. Stringers
Description: Elongated inclusions (often non-metallic) aligned in the rolling direction.
Cause: Segregation or inclusions stretched during rolling.
Impact: Reduces toughness and can lead to laminar tearing in welded structures.
81
Primary processing discontinuities from forging
1. Forging Lap
Description: A fold or overlap of metal on the surface.
Cause: Improper die design or insufficient forging pressure causing metal to flow over itself.
Impact: Creates stress concentration points that can crack under load.
2. Burst
Description: Internal rupture or cavity within the forging.
Cause: Excessive forging at low temperature or high strain rate.
Impact: Hidden defect that severely weakens the part.
3. Flaking
Description: Small, thin cracks or flakes near the surface.
Cause: Hydrogen embrittlement during cooling or improper heat treatment.
Impact: Often appears after machining; can lead to failure under stress.
4. Hydrogen Crack (HYD Crack)
Description: Cracks caused by hydrogen absorption during forging or heat treatment.
Cause: Moisture in furnace atmosphere or improper degassing of steel.
Impact: Serious defect that can propagate under stress and cause catastrophic failure.
82
What is Cold shut?
Definition
A cold shut is a discontinuity caused by incomplete fusion between two metal fronts during pouring.
It appears as a thin line or crack, often slightly rounded and smooth.
Causes
Low pouring temperature (metal loses fluidity too quickly).
Poor gating design causing turbulence or multiple flow fronts.
Contaminants or oxides at the interface.
83
Definition of a hot tear
A hot tear is a casting defect that occurs during the solidification phase when the metal is still hot but has started to solidify.
Definition
A hot tear is a crack or rupture that forms in a casting due to restrained contraction during cooling.
It typically appears as an irregular, branched crack, often near junctions or areas of abrupt section changes.
Causes
High thermal stresses caused by uneven cooling.
Poor mold design that restricts free contraction.
Sharp corners or heavy sections that cool at different rates.
84
How are shrinkage and hot tears different?
Key Difference:
Shrinkage = lack of metal feed → cavities
Hot Tear = contraction stress → cracks
85
What is the difference between porosity and blow holes?
Key Difference:
Porosity = many small, scattered voids
Blow Holes = fewer, larger cavities (often near surface)
86
Why are **water-soluble developers** prohibited for use with **water-washable penetrants**?
They can dissolve or wash away the penetrant from the surface and from defects
## Footnote
This defeats the purpose of the test.
87
What is a key risk associated with **water-soluble developers**?
* Penetrant removal risk
* Loss of sensitivity
* Compatibility issue
* Standards compliance
## Footnote
These risks compromise the reliability and accuracy of the test.
88
What does **penetrant removal risk** refer to?
Water-soluble developers can interact with the penetrant, causing it to leach out or dilute
## Footnote
This reduces the indication strength.
89
What is the consequence of **loss of sensitivity** in penetrant testing?
Flaws may not show up clearly, leading to missed defects
## Footnote
The penetrant trapped in flaws creates visible indications.
90
What is a **compatibility issue** with water-washable penetrants?
Introducing a water-based developer can wash away penetrant from shallow or fine cracks
## Footnote
Water-washable penetrants are designed to be removed with water during cleaning.
91
Which industry standards explicitly prohibit the use of **water-soluble developers** with water-washable penetrants?
ASTM E1417
## Footnote
This prohibition is due to compromised test reliability and accuracy.
92
What is the correct pairing for **water-washable penetrant**?
Dry powder developer or non-aqueous wet developer (NAWD)
## Footnote
This pairing ensures effective testing without compromising results.
93
What type of developer should be used with **solvent-removable penetrant**?
Non-aqueous wet developer
## Footnote
This ensures compatibility and effectiveness in testing.
94
What is the recommended developer for **post-emulsifiable penetrant**?
Dry powder or NAWD
## Footnote
This pairing maintains the integrity of the testing process.
95
What is **Viscosity**?
A measure of a fluid’s resistance to flow
## Footnote
Low viscosity = thin, flows easily (like water); High viscosity = thick, flows slowly (like honey).
96
How does **viscosity** affect penetrant testing?
Determines how easily the penetrant can move into surface-breaking defects
## Footnote
Low viscosity penetrants flow quickly; high viscosity penetrants flow slowly.
97
What happens with **low viscosity penetrants**?
* Flow quickly into fine cracks
* Require shorter dwell times
* Good for detecting very tight or shallow defects
## Footnote
Faster penetration due to lower resistance.
98
What are the characteristics of **high viscosity penetrants**?
* Flow slowly
* Require longer dwell times
* Preferred for rough surfaces or larger openings
## Footnote
They stay in place better due to higher resistance.
99
Fill in the blank: **Thin penetrant (low viscosity)** → _______.
Short dwell time
## Footnote
This is because penetration happens faster.
100
Fill in the blank: **Thick penetrant (high viscosity)** → _______.
Longer dwell time
## Footnote
This is necessary to ensure full saturation of flaws.
101
What factors also affect **dwell time**?
* Defect size and type
* Material surface condition
* Temperature
## Footnote
Tight cracks need more time even with low viscosity; rough surfaces slow penetration; higher temperature lowers viscosity.
102
What does **wetting ability** refer to?
How well a liquid spreads over a solid surface
## Footnote
In penetrant testing, it’s the ability of the penetrant to cover and adhere to the surface uniformly, including entering small surface discontinuities.
103
Why is **good wetting** important in penetrant testing?
Ensures the penetrant can flow into fine cracks and pores
## Footnote
Poor wetting may cause the penetrant to bead up or fail to enter defects, reducing test sensitivity.
104
List the **factors affecting wetting**.
* Surface cleanliness
* Penetrant formulation
* Temperature
## Footnote
Oil, dirt, or oxide layers reduce wetting; surface tension and viscosity of the penetrant matter; higher temperature generally improves wetting.
105
What is the **flash point** of a liquid?
The lowest temperature at which a liquid produces enough vapor to ignite in air
## Footnote
This occurs when exposed to an ignition source.
106
Why does **flash point** matter in penetrant testing?
* Safety concern
* Storage and handling
## Footnote
Penetrants and removers often contain solvents; a low flash point means higher fire risk and requires special precautions.
107
What are the **typical flash points** for non-aqueous wet developers and solvent-based penetrants?
Around 40°C to 60°C (104°F to 140°F)
## Footnote
Water-based materials generally have very high flash points, making them much safer.
108
What is the definition of an **indication** in penetrant testing?
Any visible signal on the surface after applying penetrant and developer
## Footnote
It shows where penetrant has come out of a discontinuity and may or may not indicate a defect.
109
What is a **false indication**?
A visible mark that looks like a defect but is caused by testing errors or contamination
## Footnote
Examples include residual penetrant left on the surface, developer clumping, or over-washing causing streaks.
110
What can a **false indication** lead to?
Misinterpretation and unnecessary rework
## Footnote
False indications do not represent actual defects.
111
Define **non-relevant indication**.
An indication caused by a real physical feature that is not considered a defect for the part’s service requirements
## Footnote
Examples include machining marks, threads, and surface porosity that is acceptable by specification.
112
Is a **non-relevant indication** considered a defect?
No
## Footnote
It is real but not rejectable per the acceptance criteria.
113
What is the impact of a **false indication**?
Can lead to misinterpretation and unnecessary rework
## Footnote
False indications can confuse inspectors and lead to incorrect conclusions.
114
Fill in the blank: An **indication** may or may not be a _______.
defect
## Footnote
It is just a sign that something is present.
115
What are some examples of **non-relevant indications**?
* Machining marks
* Threads
* Surface porosity acceptable by specification
## Footnote
These features are real but do not indicate a defect.
116
What are **Post-Emulsifiable Penetrants** used for?
Better control over removal, especially for critical parts
## Footnote
These penetrants require an emulsifier to make them water-washable after the dwell time.
117
What is the nature of a **Lipophilic Emulsifier**?
Oil-based
## Footnote
Applied by immersion (dip method).
118
What is a critical consideration when using a **Lipophilic Emulsifier**?
Timing is critical; over-emulsification can wash penetrant out of defects
## Footnote
The penetrant and emulsifier mix gradually.
119
What is the preferred use case for **Lipophilic Emulsifiers**?
* Rough surfaces
* Parts with complex geometry
* High-sensitivity inspections
## Footnote
Common in aerospace and critical components.
120
What is the nature of a **Hydrophilic Emulsifier**?
Water-based
## Footnote
Applied by spray or immersion, followed by water rinse.
121
What is required before applying a **Hydrophilic Emulsifier**?
Pre-rinse with water
## Footnote
The emulsifier breaks down penetrant film and allows water to remove it.
122
What is the ideal use case for **Hydrophilic Emulsifiers**?
* Large parts
* Field inspections
* Situations where water handling is easier
## Footnote
Provides more uniform removal and less risk of over-emulsification compared to lipophilic.
123
What is a key difference in **application** between Lipophilic and Hydrophilic Emulsifiers?
* Lipophilic: Immersion only
* Hydrophilic: Spray or immersion
## Footnote
Hydrophilic emulsifiers require a pre-rinse.
124
Which emulsifier type is more sensitive to timing in removal control?
Lipophilic
## Footnote
Hydrophilic emulsifiers have easier control with less risk of over-removal.
125
Typical uses for **Lipophilic Emulsifiers** include:
Aerospace, critical parts
## Footnote
They are preferred for high-sensitivity inspections.
126
Typical uses for **Hydrophilic Emulsifiers** include:
Large parts, field work
## Footnote
Ideal for situations where immersion tanks are impractical.
127
Tungsten may only occur with which of the following welding processes?
* SAW
* FCAW
* GMAW
* GTAW
GTAW: Gas Tungsten Arc Welding
128
Viscosity will:
* Not penetrate the flaws if the viscosity is high
* Cause the material to be flammable
* Determine the speed of penetration of a penetrant material
* Cause the penetrant material to draw back from areas on the surface of the part due to poor wetting caused by high viscosity
* Determine the speed of penetration of a penetrant material
129
Which of the following statements is true?
* All penetrants have emulsifiers mixed in at the time of manufacture of the penetrant.
* Visible penetrants have three sensitivity ratings.
* Visible dye penetrant exams should never be performed on the same part prior to a fluorescent penetrant exam.
* Dry powder developer should not be used with fluorescent penetrant.
Visible dye penetrant exams should never be performed on the same part prior to a fluorescent penetrant exam.
Visible dye penetrant exams should never be performed on the same part prior to a fluorescent penetrant exam because visible penetrant leaves residual dye that can contaminate the surface and interfere with the fluorescent penetrant’s ability to properly indicate flaws.
130
Solvent removable penetrant testing is considered to be Method:
* A
* B
* C
* D
Solvent removable penetrant testing is considered Method C according to the standard classification in penetrant testing methods (ASTM E1417 and similar standards).
Method A: Water-washable
Method B: Post-emulsifiable (lipophilic)
Method C: Solvent-removable
Method D: Post-emulsifiable (hydrophilic)
131
A discontinuity only found at the root pass of a weld would be:
* hot tear
* lack of penetration
* porosity
* slag
lack of penetration
132
Any break or separation of the material’s structure would be considered a:
* indication
* nonrelevant indication
* discontinuity
* defect
discontinuity
133
Sensitivity ratings are used for:
* visible penetrants only
* penetrants
* developers
* fluorescent penetrants only
Sensitivity ratings are used for fluorescent penetrants only.
Here’s why:
Fluorescent penetrants are classified by sensitivity levels (usually Levels 1–4) because they are used for high-precision inspections where defect size and detection capability matter.
Visible penetrants do not have sensitivity ratings; they are generally less sensitive and used for less critical applications.
Developers and penetrants as a general category do not have sensitivity ratings—only fluorescent penetrants do.
134
Fatigue cracks are usually due to:
* uneven heating and cooling
* corrosion
* cyclic condition (bending motion) of the part
* forging at an incorrect temperature
cyclic condition (bending motion) of the part
135
Any discontinuity caused when rolling out plate from an ingot is considered to be:
* a service discontinuity
* shrink
* an inherent discontinuity
* a processing discontinuity
a processing discontinuity
136
Fluorescent penetrant is Type:
* I
* II
* III
* IV
Fluorescent penetrant is classified as Type I in the penetrant testing system.
Type I: Fluorescent penetrant
Type II: Visible dye penetrant
Type III: Dual (fluorescent and visible) penetrant
137
The difference between the post emulsified technique and the water washable technique is:
a. the post emulsified technique takes more steps to complete.
b. the water washable is more sensitive.
c. the post emulsified is more sensitive to subsurface flaws.
d. the water washable technique can only be used with visible dye.
a. the post emulsified technique takes more steps to complete.
Explanation:
Post-emulsifiable penetrant requires an additional step: after applying the penetrant and allowing dwell time, you must apply an emulsifier before rinsing. This makes the process longer and more controlled.
Water-washable penetrant can be removed directly with water after dwell time, so it’s simpler and faster.
Sensitivity is generally higher for post-emulsifiable systems, not water-washable.
Both techniques can be used with visible or fluorescent dyes, so option d is incorrect.
Subsurface flaw detection is not relevant here because penetrant testing is for surface-breaking defects only.
138
A typical classification or type of developer is:
a. water washable.
b. water suspendible.
c. solvent removable.
d. post emulsifiable.
b. water suspendible.
Developers in penetrant testing are classified by how they are applied and their base. Common types include:
Dry powder
Water-suspendible (particles suspended in water)
Water-soluble
Solvent-removable
Water washable and post-emulsifiable refer to penetrant types, not developer types. So options a and d are incorrect.
Option c (solvent removable) is also a valid developer type, but the question asks for a typical classification, and water-suspendible is one of the most common.
139
A linear or multi-facited indication at the start or stopping point of a weld is likely to be:
a. a HAZ cracking condition.
b. a crack due to excessive hydrogen content.
c. a crater crack.
d. a toe crack.
c. a crater crack.
140
A hydrophilic emulsifier concentration is verified by the use of:
a. a refractometer.
b. a hydrometer.
c. a meniscus lens.
d. TAM pan.
a. a refractometer.
Hydrophilic emulsifier concentration is typically checked using a refractometer, which measures the refractive index of the solution. The refractive index correlates with the concentration of the emulsifier in water.
Hydrometer measures density, not refractive index, so it's not commonly used for this purpose.
Meniscus lens is unrelated to concentration measurement.
TAM pan is used for measuring penetrant removability or performance, not emulsifier concentration.
141
Which of the following may not be used with visible dye penetrant examinations?
a. Nonaqueous developer
b. Hydrophilic emulsifier
c. Dry developer
d. Solvent cleaner
b. Hydrophilic emulsifier.
Visible dye penetrant examinations use penetrants that can be removed by water (water-washable) or solvent, and developers like nonaqueous, dry, or water-suspendible can be used.
Hydrophilic emulsifier is part of the post-emulsifiable penetrant system, which is typically used with fluorescent penetrants, not visible dye penetrants.
Therefore, hydrophilic emulsifier is not used in visible dye penetrant testing.
142
The indication formed by two closely mating parts such as press fits would be:
a. a relevant indication.
b. a nonrelevant indication.
c. a false indication.
d. a flaw.
b. a nonrelevant indication.
143
The indication formed by two closely mating parts such as press fits would be:
a. a relevant indication.
b. a nonrelevant indication.
c. a false indication.
d. a flaw.
b. a nonrelevant indication.
144
Viscosity is:
a. the ability of the fluid to wet the part surface.
b. the "thickness" or "consistency" of the fluid and its ability to flow.
c. capillary action.
d. the tendency of the penetrant to form fumes at the part surface and combust.
b. the "thickness" or "consistency" of the fluid and its ability to flow.
145
An example of a nonrelevant indication is:
a. penetrant on the part from the inspector's hands.
b. penetrant bleed out from a press fit.
c. penetrant bleed out from slag.
d. penetrant on the part from touching another part with dye on it.
b. penetrant bleed out from a press fit.
Nonrelevant indications occur due to part geometry or design features, not actual flaws.
A press fit creates a very tight joint where penetrant can get trapped and later bleed out, even though there is no discontinuity.
a and d (penetrant from inspector’s hands or from touching another part) are examples of false indications caused by contamination or handling errors.
c (penetrant bleed out from slag) is a relevant indication, because slag is a discontinuity.
146
The greatest danger with the water washable technique is:
a. over washing the parts.
b. examinations being done in high temperatures.
c. water contamination of the emulsifier.
d. insufficient wash time.
a. over washing the parts.
In the water-washable penetrant technique, the penetrant is removed directly with water after dwell time.
The greatest risk is over-washing, which can remove penetrant from actual discontinuities, leading to missed defects and false negatives.
b. high temperatures can affect dwell time but is not the primary danger.
c. water contamination of the emulsifier applies to post-emulsifiable systems, not water-washable.
d. insufficient wash time usually leaves excess penetrant on the surface, causing background noise, but it's less critical than over-washing.
147
Incomplete removal of the penetrant when using a post emulsified penetrant can be corrected by:
a. decreasing the water temperature.
b. clean the part and reprocess completely with a longer emulsifying time.
c. reapply emulsifier.
d. use a solvent wipe.
b. clean the part and reprocess completely with a longer emulsifying time.
If penetrant is not fully removed during a post-emulsifiable process, it usually means the emulsification step was insufficient.
The proper corrective action is to start over: clean the part thoroughly and repeat the process, ensuring a longer emulsifier dwell time for complete removal.
a. decreasing water temperature does not address incomplete removal.
c. reapply emulsifier is not recommended because the process must be controlled and consistent; partial reapplication can lead to uneven results.
d. use a solvent wipe is not allowed because it can smear penetrant and compromise test integrity.
148
The purpose of the developer is:
a. provide blotting and a contrasting background.
b. assist in drying the part and blotting the dye from the flaw.
c. provide a contrasting background and keep the bleedout the same size as the flaw.
d. keeping the brilliance of the dye consistent.
a. provide blotting and a contrasting background.
The developer in penetrant testing serves two main purposes:
Blotting action: It draws penetrant out of surface-breaking discontinuities to make indications visible.
Contrasting background: It provides a light, uniform background so the penetrant indication stands out clearly.
b mentions drying the part, which is not the developer’s primary role.
c is incorrect because the bleed-out often spreads beyond the flaw size; the developer does not keep it the same size.
d is incorrect because maintaining dye brilliance is not the developer’s function.
149
One of the most important steps in obtaining a valid liquid penetrant exam result is:
a. applying the dye with an electro static spray.
b. precleaning the surface properly.
c. allowing at least 10 minutes of drying time between cleaning the excess dye off and applying the developer.
d. using fluorescent dye for the exam
b. precleaning the surface properly.
150
An acceptable form of precleaning prior to applying the penetrant would be:
a. solvent cleaning.
b. sand blasting.
c. acid etching.
d. shot blasting.
a. solvent cleaning.
Solvent cleaning is an acceptable and common pre-cleaning method before applying penetrant because it removes oils, grease, and contaminants without damaging the surface.
Sand blasting and shot blasting can smear metal or create surface roughness that traps penetrant, leading to false indications.
Acid etching is only used in special cases (e.g., removing smeared metal after machining) and is not a standard pre-cleaning method for routine penetrant testing.
151
Capillary action would describe:
a. the ability of the penetrant to enter and exit small discontinuities or openings.
b. the ability of the developer to soak up the dye as it exits the openings.
c. the action that emulsifies the penetrant on the surface.
d. how emulsifiers render the penetrant water washable.
a. the ability of the penetrant to enter and exit small discontinuities or openings.
152
The most sensitive developer is:
a. aqueous suspendible developer.
b. aqueous soluble developer.
c. dry developer.
d. nonaqueous wet developer.
d. nonaqueous wet developer.
Nonaqueous wet developer (NAWD) is considered the most sensitive type of developer because:
It provides excellent contrast and uniform coverage.
It is typically used in aerosol form, which ensures a thin, even layer.
It works well with both visible dye and fluorescent penetrants, especially in critical inspections.
Dry developer is less sensitive and mainly used for fluorescent penetrants.
Aqueous suspendible and aqueous soluble developers are effective but generally less sensitive than NAWD.
153
A reason to use fluorescent penetrants over visible penetrants is:
a. easier to remove from the part.
b. easier to see small fine discontinuity indications.
c. faster to process the parts.
d. the residual penetrant left on the part would not be visible under normal light and therefore eliminate the need for post cleaning.
b. easier to see small fine discontinuity indications.
154
A reason to use fluorescent penetrants over visible penetrants is:
a. easier to remove from the part.
b. easier to see small fine discontinuity indications.
c. faster to process the parts.
d. the residual penetrant left on the part would not be visible under normal light and therefore eliminate the need for post cleaning.
b. easier to see small fine discontinuity indications.
155
The acceptance criteria is normally based on:
a. the size of the flaw.
b. the pentrant dwell time.
c. the development dwell time.
d. the size of the penetrant bleed out.
d. the size of the penetrant bleed out.
155
A typical indication found on bar stock would be:
a. lack of penetration.
b. shrink.
c. lamination.
d. seam.
d. seam.
155
The acceptance criteria is normally based on:
a. the size of the flaw.
b. the pentrant dwell time.
c. the development dwell time.
d. the size of the penetrant bleed out.
d. the size of the penetrant bleed out.
156
Examination of parts between 40°F and 50°F generally require:
a. more developer application.
b. longer wash times.
c. penetrant with higher viscosity ratings.
d. doubling the penetrant dwell time.
d. doubling the penetrant dwell time.
157
If the weld and 1/2" of adjacent base material is determined to be the examination area, what are the requirements for precleaning the part?
a. The weld and 1" adjacent base material
b. The weld and 1/2" adjacent base material
c. The weld and 2" of adjacent base material
d. The weld and 1 1/2" of adjacent base material
a. The weld and 1" adjacent base material.
According to most penetrant testing standards (such as ASME Section V, Article 6), the precleaning area must extend beyond the examination area by at least 1/2 inch on all sides.
If the examination area is the weld plus 1/2" of adjacent base material, then you need to clean an additional 1/2" beyond that.
158
Emulsifier is contained in:
a. solvent removable penetrant.
b. post emulsifiable penetrant.
c. water washable penetrant.
d. water soluble developer.
d. water soluble developer.
159
During a penetrant exam the technician noticed a linear penetrant indication on the part after bumping it against the station rack that wasn't there previously. This indication would be classified as:
a. relevant.
b. nonrelevant.
c. false.
d. rejectable.
c. false.
160
The two types of aqueous developers are:
a. nonaqueous and wet suspendible.
b. dry and nonaqueous developers.
c. wet suspendible and dry developers.
d. wet suspendible and wet soluble.
d. wet suspendible and wet soluble.
161
A large reduction in blacklight intensity readings could indicate:
a. a dirty lens.
b. positioning the black light too close to the sensor.
c. a fully charged battery.
d. a cut in the electrical insulation on the cable.
a. a dirty lens.
162
When forging material at an incorrect temperature, the most likely flaw that may result would be:
a. shrink.
b. forging porosity.
c. burst.
d. laps.
c. burst.
163
A process control check would not be required for:
a. water washable penetrants.
b. aqueous wet soluble developer.
c. emulsifier.
d. nonaqueous wet developer.
d. nonaqueous wet developer.
164
The most likely choice of techniques for testing a stainless steel pipe weld in a power plant would be:
a. solvent removable technique.
b. lipophilic post emulsifiable technique.
c. water washable technique.
d. hydrophilic post emulsifiable technique.
a. solvent removable technique.
165
Which of the following could be classified as a processing discontinuity?
a. Fatigue crack
b. Lack of penetration
c. Stress corrosion crack
d. Corrosion
b. Lack of penetration
166
Visible dye liquid penetrant:
a. is available in various sensitivities.
b. is more sensitive to the eyes than fluorescent penetrant.
c. is easier to use in the field than fluorescent dye penetrant testing.
d. is only allowed to be used with dry powder developer.
c. is easier to use in the field than fluorescent dye penetrant testing.
167
The least sensitive technique is:
a. Solvent removable technique.
b. water washable technique.
c. post emulsifiable technique.
d. the sensitivity is the same for all techniques.
b. water washable technique.
Post-emulsifiable (lipophilic or hydrophilic) systems are the most sensitive.
Solvent removable is moderately sensitive.
Water washable is the least sensitive, because the penetrant contains surfactants that make it easier to wash off, which can reduce its ability to stay in very fine discontinuities.
d. the sensitivity is the same for all techniques is incorrect because sensitivity varies significantly between methods.
168
The "thickness" of the penetrant controls the flow of the penetrant and refers to:
a. wetting ability.
b. surface tension.
c. viscosity.
d. capillary action.
c. viscosity.
169
If a dry developer is contaminated, it will be noticeable by:
a. the results of the hydrometer test.
b. the fluorescing in the developer bin.
c. the use of the refractometer.
d. during the drying of the part.
b. the fluorescing in the developer bin.
170
A painted or coated surface:
a. can be examined as is.
b. is acceptable to test if the thickness if under 2 mils.
c. must always have the coating removed.
d. will not affect the examination.
c. must always have the coating removed.
171
The act of "evaluation" would be:
a. determining if the discontinuity is acceptable according to the acceptance criteria.
b. reading and understanding the spec or procedure for performing liquid penetrant examination.
c. determining what caused the indication.
d. filling out the report properly for the penetrant examination.
a. determining if the discontinuity is acceptable according to the acceptance criteria.
In NDT, evaluation means assessing the indications found during the inspection and deciding whether they meet the acceptance criteria specified by codes, standards, or customer requirements.
172
Dry developer would be best used:
a. on rough surfaces with a visible dye.
b. on a smooth machined surface.
c. on a relatively rough surface when using fluorescent penetrant.
d. when using visible dye with the solvent removable technique.
c. on a relatively rough surface when using fluorescent penetrant.
Dry developer is best suited for fluorescent penetrant testing on rough surfaces because:
It can adhere better to irregular surfaces compared to nonaqueous wet developers.
It provides good blotting action without excessive background fluorescence.
a (rough surface with visible dye) is incorrect because dry developer is rarely used with visible dye penetrants; nonaqueous wet developer is preferred for visible dye.
b (smooth machined surface) is better for nonaqueous wet developer.
d (visible dye with solvent removable technique) is incorrect because dry developer is not typically used with visible dye penetrants.
173
Liquid penetrant is not recommended for:
a. porous products.
b. aluminum.
c. powdered metal products.
d. glass.
a. porous products.
174
Which of the following are provided in differing levels of sensitivity?
a. Both visible and fluorescent penetrants of all techniques
b. Only fluorescent penetrants
c. Only post emulsifiable fluorescent penetrants
d. Only visible dye penetrants
b. Only fluorescent penetrants
175
Which of the following is an advantage of solvent removable penetrants over water washable penetrants?
a. No special lighting is necessary during inspection
b. Solvent removable penetrants are faster than water wash
c. Solvent removable does not require developer
d. Solvent removable is easier to use in the field and remote locations
d. Solvent removable is easier to use in the field and remote locations
176
The difference between the post emulsified technique and the water washable technique is:
a. the post emulsified technique takes more steps to complete.
b. the water washable is more sensitive.
c. the post emulsified is more sensitive to subsurface flaws.
d. the water washable technique can only be used with visible dye.
a. the post emulsified technique takes more steps to complete.
177
A typical classification or type of developer is:
a. water washable.
b. water suspendible.
c. solvent removable.
d. post emulsifiable.
b. water suspendible.
ASNT Penetrant Testing
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