nondestructive tests

8/10/2019 nondestructive tests

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Non Destructive Testing

It is the use of techniques toIt is the use of techniques toinspect or measure withoutinspect or measure without

causing harm to the materialcausing harm to the materialor structureor structure


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Methods of NDT

VisualVisual

L i q u i d P e n

e t r a n t

M a g n e t i c P a r t i c l e

E d d y C u r r e n t

U l t r a s o n i c

X - r a y

M i c r o w a v e

A c o u s t i c E m i s s i o n

T h e r m o g r a p h y

La s e r I n t e r f e r o m e t r y

Re p lica tio n

F lu x Le a ka g e

A c o u s t i c M i c r o s c o p y

M a g n e t i c M e

a s u r e m e n

t s

T a p T e s t i n g


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Penetrant Testing


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Uses of Penetrant Testing

It is used for Surface DiscontinuitiesIt is used for Surface DiscontinuitiesCracksCracks

PorosityPorositySeamsSeams

LapsLaps

Leak DetectionLeak Detection


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Visible Type


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Preclean & Penetrant Application


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Cleaning & Developing


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Inspection


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Fluorescent Type


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Preclean & Penetrant Application


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Inspection


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Examples of results


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Magnetic Particle Inspection(MPI)


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Magnetic Particle Inspection

AA nondestructivenondestructive test method whichtest method which provides for the detection of surface and provides for the detection of surface andnear surface discontinuities innear surface discontinuities inferromagneticferromagnetic materials.materials.


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Types of defect that can bedetected with MPI

CracksCracks LapsLaps

SeamsSeams VoidsVoids

PitsPits Subsurface holesSubsurface holes


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Before inspection After inspection

Cracks emanating from a hole


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Available Techniques at MSB

Flexible conductive cableFlexible conductive cable

Yoke magnetizationYoke magnetization

ProdsProds

Central conductor Central conductor

HandscanHandscan for floor thickness monitoringfor floor thickness monitoring


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Flexible conductiveFlexible conductivecablecable

Yoke magnetization forYoke magnetization forinducing longitudinal field inducing longitudinal field


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Central conductor forCentral conductor forcircular field circular field

Prods techniqueProds technique


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Floor Thickness Monitoring

TheThe HandscanHandscan

Ideal to detectIdeal to detect

corrosion pit on floorcorrosion pit on floorof large tanksof large tanks

Examples of test results


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FF luorescentluorescent indicatioindicatio nn of of aacrack in a bearingcrack in a bearing

FF luorescentluorescent indication oindication o ffcracks at a fastener holecracks at a fastener hole


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Indication ofIndication ofcracks in a weldcracks in a weld

Indication of cracksIndication of cracksin ain a boltbolt


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FFluorescentluorescent indication ofindication of

a crack in castinga crack in casting

AA crack at a sharp radiuscrack at a sharp radius


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Fluorescent indication of cracks in a drive shaft


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Fluorescent indication

of a crack in thecrane hook

Indication of a crack ina saw blade


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Advantages of MPI Test method process is quick and simpleTest method process is quick and simple

Highly sensitive to the detection of surfaceHighly sensitive to the detection of surfaceand slightly subsurfaceand slightly subsurface indicationsindications

Test method process may often workTest method process may often workthrough contaminant layers and coatingthrough contaminant layers and coating

thicknessthickness


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Limitations of MPI

Test material must be ferrousTest material must be ferrous

Demagnetisation is often necessaryDemagnetisation is often necessaryafter after inspectioninspection


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Radiographic Testing (RT)


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Radiographic Testing


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Film Radiography

Top view of developed film

X-ray film

The film is placed at the back ofthe specimen.

= more exposure

= less exposure

The film darkness(density) will vary withthe amount of radiation

reaching the filmthrough the test object.


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EquipmentThe MSB is equipped with two X RayThe MSB is equipped with two X RayTubesTubes

A maximum of 300KV can be achievedA maximum of 300KV can be achieved providing inspection up to about 50mm of providing inspection up to about 50mm of

mild steel.mild steel.


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Types of defect that can bedetected with RT

PorosityPorosity

Slag inclusions in weldsSlag inclusions in welds

Tungsten inclusionsTungsten inclusions Lack of fusion or penetrationLack of fusion or penetration

Forging lapsForging laps Cracks (although not too suitable)Cracks (although not too suitable)


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Advantages of RT Can be used with most materialsCan be used with most materials

Discloses fabrication errorsDiscloses fabrication errors

Reveals structural discontinuitiesReveals structural discontinuities

Provides a permanent visual imageProvides a permanent visual image


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Limitations of RT

High safety considerationsHigh safety considerations

Specimen needs to be accessed on atSpecimen needs to be accessed on atleast two sidesleast two sides

Difficult on complex geometryDifficult on complex geometry


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PorosityPorosity


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Incomplete penetrationIncomplete penetration


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Tungsten inclusionsTungsten inclusions


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CracksCracks


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Slag inclusionsSlag inclusions


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Uses of Ultrasonic Testing

Detection of Flaws in MaterialsDetection of Flaws in Materials

Thickness MeasurementThickness Measurement


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Detection of Flaws in Welds

Transmitter Receiver (TR) probes are ideallysuited for the detection of near-to-surface


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suited for the detection of near to surfacediscontinuities and for thickness measurementsof thin objects.


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Other Uses of UT

T f D f h b


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Types of Defects that can bedetected with UT

CracksCracks

MisalignmentMisalignment

PorosityPorosity

InclusionsInclusions

Surface ConditionsSurface Conditions

PittingPitting


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Advantages of UTHigh Sensitivity which permits detection ofHigh Sensitivity which permits detection ofminute defects.minute defects.High Penetrating Power (6 to 7High Penetrating Power (6 to 7 metresmetres inin

steel)steel)High accuracy of Flaw positioning andHigh accuracy of Flaw positioning andSizingSizingIt needs access to only one surface of theIt needs access to only one surface of theSpecimenSpecimen


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Limitations of Ultrasonic TestingComplex Geometry of the test specimenComplex Geometry of the test specimencauses problems during inspection.causes problems during inspection.

Defect orientation affects detect abilityDefect orientation affects detect ability


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TechniquesTechniquessuitable forsuitable for

Surface DefectsSurface Defects

Liquid PenetrantLiquid Penetrant

Magnetic ParticleMagnetic Particle

TechniquesTechniquessuitable for Subsuitable for Sub --

Surface DefectsSurface Defects

RadiographyRadiography

UltrasonicUltrasonic

nondestructive tests

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