Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MPI > 2: Methods & Techniques > Flashcards

2: Methods & Techniques Flashcards

1
Q

What are 3 ways to figure out the magnetic field direction?

A
  1. Right Hand Rule
  2. Pie Gauges
  3. Quantitative Quality Indicators (QQI’s)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What units do magnetic field indicators measure in?

A

Gauss or Tesla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a digital type of Gauss Meter?

A

Hall Effect Meter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Main difference between circular and longitudinal magnetism?

A

Longitudinal has external poles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Solenoids produce what kind of field?

A

Longitudinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do defects show up?

A

Same direction as current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is one of the best ways to detect subsurface discontinuities when using half wave DC or half rectified AC?

A

Circular magnetization with prods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Coils are typically around what type of frame?

A

Molten

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a pole piece?

A

Stuck on the end of a part to create length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Parts less than what require a pole piece?

A

Two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Parts exceeding what max length need to be inspected in separate pieces?

A

18 inches (26 cm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the fill factor?

A

Diameter of part compared to diameter of coil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When using DC current, amps depend on what thickness?

A

Cross-sectional thickness

Direct Contact Formula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are QQI’s used for?

A

Ensure proper technique is used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Wet fluorescence is often referred to as what? (2)

A

Background or background fluorescent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is furring caused?

A

Excessive longitudinal field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Contact area is referred to what?

A

Cross section

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the rule for how close prods are together?

A

2”-8”

6” is good

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When using prods and a material less than 3/4” ..what amperage should you use?

A

90-115 amps/inch of spacing

3.5-4.5 amps/mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When using prods and a material more than 3/4” thick, what amperage should you use?

A

100-125 amps/inch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the formula for low fill factor in a coil?

A

45,000/(L/D) x 1/n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the formula for high fill factor in a coil?

A

35,000/(L/D)+2 x 1/n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

An effective inspection area is what?

A

4x diameter of the conductor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is amperage based on when using a central conductor?

A

Wall thickness and diameter of centre conductor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Doubling the radius will do what to the flux density?
Cut flux density in half
26
What are the 6 basic steps on an MPI?
1. Part prep 2. Mag methods 3. Application of particle 4. Inspection & Interpretation 5. Demagnetization 6. Post Cleaning
27
What type of cleaner do you HAVE to have around welders?
Non-chlorinated | Will create lethal phosgene
28
What is the disadvantage of ferromagnetic coatings on a part you are trying to inspect?
Could provide false indications and mask discontinuities
29
What best results, are characteristics of particles do we want?
High permeability and low retentivity
30
What is the idea particle density?
5-8x thicker than water
31
In wet applications, what is required in order to avoid settling of particles?
Constant agitation
32
What are “contrast aid paints”?
White pigment suspended in quick drying, colourless solvent
33
Choosing particles depends on what 3 things?
1. Type of defect 2. Size of surface defect 3. Convenience
34
1 advantage and 1 disadvantage of dry visible method?
Less sensitive to tiny surface defects but better for finding sub surface flaws
35
What are pie gauges made out of?
Low carbon steel pie sections, furnace brazed and copper plated
36
What is a multidirectional unit?
Capable of producing both field at the same time
37
Describe the current in the central conductor method?
Strong circular field around conductor and specimen BUT no current through specimen itself
38
AC is used to induce eddy currents into parts during which method because it can’t be properly inspected using direct contact or central conductor techniques?
Induced current technique
39
Core material should have a minimum length of what?
Equal to diameter of ring shaped test piece BUT no less than 152 mm long
40
What is the most common method to test welds?
Prod method
41
Inspection of tubes, pipes, shafts or small ferromagnetic parts are generally done with what?
Portable coils
42
Why would Vector Fields occur?
Imbalanced circular and longitudinal fields in multidirectional magnetization
43
How do you calculate amperage for a low fill conductor?
12-32 amps/mm of (CC diameter + 2x wall thickness)
44
Where is the field strength strongest in a solid nonmagnetic conductor?
Surface of part
45
What is the field strength proportional to in a solid nonmagnetic conductor?
Size of conductor | Will increase proportionally to increase in current
46
Where is the field strength greatest in a solid MAGNETIC conductor?
Below the surface
47
For ferromagnetic conductors, field strength within is dependant on what?
Permeability
48
What is the field strength of a hollow nonmagnetic AND magnetic conductor?
Zero in centre of hollow section and greatest at outer surface
49
What is referred to as “skin effect”?
AC’s tendency to flow near surface of conductor
50
Detergent and aqueous cleaners are usually used for what contaminants?
Light oils, grime, soil/dirt and mild grease
51
Solvent cleaners (like non halogenated petroleum naphtha) are most commonly used for what contaminants?
Mild - moderate grease and oils | However they may leave a thin film or residue
52
Describe steam cleaning:
A form of alkaline or detergent cleaning where the solution is pressurized
53
Vapour degreasing is very effective for removing what?
Heavy souls, grease and oils
54
Steels become brittle with what type of cleaner?
Acid based
55
Titanium and nickel alloys are attacked by what type of cleaner?
Products containing halogen and sulphur
56
Particle selection is based on what?
Sensitivity required and suspected discontinuities
57
Choice of current is primarily governed by what?
Type and location of suspected discontinuities
58
What is the tail stock?
The moveable section of headstock
59
Describe the magnetic field while using indirect current with a central conductor:
Field on inside surface is smaller and opposite than what’s produced on outside
60
In a stationary magnetizing coil, the field direction is...
Parallel to axis of coil
61
Ratio of length to diameter must be at least what for coil magnetization to be effective?
2:1
62
Longer parts can actually be demagnetized by the earths magnetic field, therefor the axis should always be placed in what direction?
Long axis east to west direction

MPI (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions