non-destructive testing (chapter 6)
TRANSCRIPT
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
1/63
Non-Destructive Testing
allow parts and material to be inspected andmeasured w/o damaging them
Allow inspection w/o interfering with aproducts final use
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
2/63
Six Most Common NDT Methods
Visual
Liquid Penetrant
Magnetic Ultrasonic
Eddy Current
X-ray
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
3/63
Visual Inspection
Basic principle illuminate the test specimen with light Examine the specimen with the eye
Used to
To magnify defects which can not be detectedby the unaided eye
To assist in the inspection of defects To permit visual checks of areas not accessible
to unaided eye.
Most widely used of all the NDT tests Simple easy to apply, quickly carried out
and usually low in cost
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
4/63
Visual Inspection Equipment Magnifying glass
Magnifying mirror
Microscope
Borescope Endoscope or endoprobes
Felxible Fiber Optic Borescope Working length are normally 60 to 365 cm with
diameters from 3-12.5 mm
Video Imagescope
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
5/63
Borescope
Rigid Flexible fiber optic
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
6/63
Robotic crawlers permit observation inhazardous or tight areas, such as airducts, reactors, pipelines.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
7/63
X-ray or Radiography Testing
This method consists in passing a mixedbeam of x-rays through the object andstudying the shadow formed either on
fluorescent screen or photographic film
Any imperfection will absorb the rays lessbecause of less density
The position of imperfection is marked onthe film by dark areas
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
8/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
9/63
X-ray or Radiography Testing
The radiation used inradiography testing isa higher energy(shorter wavelength)
version of theelectromagneticwaves that we see asvisible light. Theradiation can comefrom an X-raygenerator or aradioactive source.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
10/63
Film Radiography
Top view of developed film
X-ray film
The part is placed between the radiation
source and a piece of film. The part will
stop some of the radiation. Thicker and
more dense area will stop more of the
radiation.
= more exposure
= less exposure
The film darkness
(density) will vary with
the amount of radiation
reaching the film throughthe test object.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
11/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
12/63
X-Rays Images
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
13/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
14/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
15/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
16/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
17/63
Liquid penetrant inspection
extension of visual inspection
for detection of surface flaws
two kinds ; dye penetrant and
fluorescent penetrants
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
18/63
Liquid penetrant inspection is amethod that is used to reveal
surface breaking flaws bybleedout of a colored orfluorescent dye from the flaw.
Liquid Penetrant Testing
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
19/63
The technique is based on the ability of
a liquid to be drawn into a "clean"surface breaking flaw by capillary action.
Fluorescentpenetrant onsurface seeps into
the crack.
PenetrantPenetration
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
20/63
Emulsifies is applied to the penetrant. Emulsifier mixes
with penetrant on the surface, but penetrant in thecrack is not emulsified. Emulsifier makes the mixturewashable .
Liquid Penetrant Testing
Penetrant only
Emulsifier and penetran
Emulsification
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
21/63
Water spray removes the emulsified penetrant. Waterremoves the surface film as well.
Liquid Penetrant Testing
Penetrant only
water
Rinse
Li id P t t T ti
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
22/63
A developer is applied to pull the trapped penetrant out thedefect and spread it on the surface where it can be seen.
Liquid Penetrant Testing
Penetrant
Development
developer
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
23/63
Black light causes the penetrant to glow in
dark.
Liquid Penetrant Testing
Penetrant
Inspection
Developer
Black Light
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
24/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
25/63
Ultrasonic Testing
The propagation of sound waves throughsolid materials have been used to detecthidden crack, voids, porosity and other
internal discontinuities.
High frequency sound waves reflect fromflaws in predictable ways, producingdistinctive echo patterns that can bedisplayed and recorded by portableinstruments
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
26/63
f
plate
crack
0 2 4 6 8 10
initial
pulse
crack
echo
back surface
echo
Oscilloscope, or flaw
detector screen
Ultrasonic testing
We can measure the distance/depthfor flaw in the sample by measuringthe echo distance from the initial
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
27/63
Flaw size can also be interpreted
It is used on aircraft, the power stationsgenerating plant, or welds in pressure vessels atan oil refinery or paper mill.
technician training and skill is required.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
28/63
Eddy current
When an energized coil is broughtnear to the surface of a metal orconducting component, eddy current
set up a magnetic field that tend tooppose the original magnetic field.The impedance of coil in close
proximity to the specimen is affectedby the presence of the induced eddycurrents in the specimen
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
29/63
when the eddy currents in the
specimen are distorted by thepresence of the flaws or materialvariations, the impedance in the coilis altered. This changes is measuredand displayed in a manner thatindicates the types of flaw ormaterial condition
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
30/63
Eddy Current Testing
Conductivematerial
CoilCoil'smagnetic field
Eddycurrents
Eddy current'smagnetic field
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
31/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
32/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
33/63
Eddy Current Testing
Eddy current testing is particularly well suited for detecting
surface cracks but can also be used to make electricalconductivity and coating thickness measurements. Here a
small surface probe is scanned over the part surface in an
attempt to detect a crack.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
34/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
35/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
36/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
37/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
38/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
39/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
40/63
Application
Detect defect under coated material
Detect defect that are so small
To check welds
Application inside tube such as in heatexchanger
Detect surface crack, pit, subsurface
crack, corrosion inner surface
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
41/63
Magnetic Particle Testing
Magnetic particle inspection is amethod that can be used to find
surface and near surface flaws inferromagnetic materials such assteel and iron.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
42/63
Magnetic Particle Testing
The technique uses the principle thatmagnetic lines of force (flux) will be
distorted by the presence of a flaw in a
manner that will reveal it's presence.
S N S NN S
IRON POWDER
CRACK
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
43/63
Magnetic Particle Testing
N S
IRON POWDER
CRACK
COIL
(COMPLETELY
CLOSED MAGNET)
M ti P ti l T ti
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
44/63
Magnetic Particle Testing
The flaw (for example, a crack) is located from
the "flux leakage", following the application offine iron particles, to the area under examinatioThere are variations in the way the magnetic fielis applied.
N S
IRON POWDER
S N
N S
IRON POWDER
CRACK
CRACK
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
45/63
Magnetic Particle Testing
The iron particles can be applied dry or wet;suspended in a liquid, colored or fluorescent.While magnetic particle inspection is primarily
used to find surface breaking flaws, it can also beused to locate sub-surface flaws. But it'seffectiveness quickly diminishes depending on theflaw depth and type.
Magnetic Particle Testing
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
46/63
Magnetic Particle Testing
Surface irregularities and scratches can givemisleading indications. Therefore it is necessary toensure careful preparation of the surface before
magnetic particle testing is undertaken.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
47/63
Advantages and limitation
Advantages Simplicity of operation and application Complex shapes can be tested Detect small fine crack
Low cost
Disadvatages Restricted to ferromagnetic materials Restricted to surface or near surface flaws Required cleaning process Need more than two magnetization in order to
inspect complex shape.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
48/63
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
49/63
Common Application of
NDT
Inspection of RawProducts
Inspection FollowingSecondary Processing
In-Services DamageInspection
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
50/63
Inspection of Raw Products
Forgings,Castings,Extrusions,etc.
I ti F ll i
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
51/63
MachiningWeldingGrindingHeattreatingPlatingetc.
Inspection Following
Secondary Processing
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
52/63
Cracking
CorrosionErosion/Wear
Heat Damage
etc.
Inspection For
In-Service Damage
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
53/63
Power Plant Inspection
Probe
Signals produced
by various
amounts of
corrosion
thinning.
Periodically, power plants are
shutdown for inspection.Inspectors feed eddy current
probes into heat exchanger
tubes to check for corrosion
damage.
Pipe with damage
Wi R I ti
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
54/63
Wire Rope InspectionElectromagnetic devices andvisual inspections are used to
find broken wires and otherdamage to the wire rope thatis used in chairlifts, cranes andother lifting devices.
St T k I ti
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
55/63
Storage Tank InspectionRobotic crawlers useultrasound to inspectthe walls of largeabove ground tanksfor signs of thinningdue to corrosion.
Cameras onlongarticulating
arms are usedto inspectundergroundstorage tanksfor damage.
Ai ft I ti
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
56/63
Aircraft Inspection Nondestructive testing is used
extensively during the
manufacturing of aircraft. NDT is also used to find cracks
and corrosion damage duringoperation of the aircraft.
A fatigue crack that started at thesite of a lightning strike is shown
below.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
57/63
Jet Engine InspectionAircraft engines are overhauled after
being in service for a period of time.
They are completely disassembled,cleaned, inspected and thenreassembled.
Fluorescent penetrant inspection isused to check many of the parts for
cracking.
C h f U it d Fli ht 232
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
58/63
Sioux City, Iowa, July 19, 1989A defect that went
undetected in anengine disk was
responsible for
the crash of
United Flight 232.
Crash of United Flight 232
Press re Vessel Inspection
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
59/63
Pressure Vessel InspectionThe failure of a pressure vessel
can result in the rapid release of a
large amount of energy. To protectagainst this dangerous event, the
tanks are inspected using
radiography and ultrasonic testing.
Rail Inspection
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
60/63
Rail Inspection
Special cars are used to
inspect thousands of miles ofrail to find cracks that couldlead to a derailment.
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
61/63
Bridge Inspection Corrosion, cracking and
other damage can allaffect a bridgesperformance.
Bridges get a visualinspection about every 2years.
Some bridges are fittedwith acoustic emissionsensors that listen forsounds of cracks growing.
Pipeline Inspection
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
62/63
NDT is used to inspect pipelines toprevent leaks that could damage the
environment. Visual inspection,radiography and electromagnetictesting are some of the NDTmethods used.
Remote visual inspection usinga robotic crawler.
Radiography of weld joints.
Magnetic flux leakage inspection.This device, known as a pig, isplaced in the pipeline and collectsdata on the condition of the pipe as itis pushed along by whatever is beingtransported.
Pipeline Inspection
Special Measurements
-
8/13/2019 Non-Destructive Testing (CHAPTER 6)
63/63
Special Measurements
Boeing employees in Philadelphia were given the privilegeof evaluating the Liberty Bell for damage using NDT
techniques. Eddy current methods were used to measurethe electrical conductivity of the Bell's bronze casing atvarious points to evaluate its uniformity.