Pre-Cleaning (2) Flashcards
1
Q
Why do we Pre-Clean?
A
- ensure discontinuity openings are open to surface
- prevent false indications
- prevent “masking” of indications
- prevent adverse reaction with penetrant
2
Q
LPI cleaning methods (non-abrasive)
A
- Detergent
- Solvent
- Alkaline
- Acid Etch
- Steam
- Ultrasonic
- Salt Bath De-Scale
- Vapour Degrease
3
Q
Detergents are used for:
A
- light oils
- dirt
- grime
4
Q
Solvents are used for:
A
- oils
- grease
- dirt
5
Q
Alkaline’s are used for:
A
- oils
- grease
- dirt
6
Q
Acid Etches are used for:
A
- scale
- rust
- oxides
- metal smearing
7
Q
Steams are used for:
A
- dirt
- oils
- grease
- light scale
8
Q
Ultrasonic’s are used for:
A
- light grime
9
Q
Salt Bath De-scales are used for:
A
- heavy scales
- oxides
10
Q
Vapour degreasers are used for:
A
- grease
11
Q
Least damaging abrasive methods can be used, these include:
A
- plastic scrapers
- scotch brite
- shell blasting
12
Q
Long exposures to Alkaline Cleaners and salt baths will cause pitting on __, ___, and ___ parts
A
- aluminium
- magnesium
- titanium
13
Q
Chemicals containing chlorine and fluorides can promote intergranular corrosion cracking in ___ ____.
A
stainless steels
14
Q
Chemicals containing sulphur and sulphides can induce stress corrosion cracking in ___, ____, and ___ products.
A
- nickel
- stainless steel
- titanium
15
Q
Impact of temperature
A
- high temperatures can dull and/or dry the penetrant
- high temperatures can recrystallize some metals
- low temperatures = longer dwell times
