[ z» Ì£ ÉZÅ Non rDestructive Testing

Non Destructive Testing

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Radiographic Testing

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Rayleigh Scattering

Pair Production

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RT

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)IQI (

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External concavity(insufficient fill)

Excess weld metal

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Lack of side wallfusion

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Internal rootundercut

External undercut

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Linear Misalignment Burn through Spatter

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Crater crack orStar crack

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Arc strike

Cap undercut

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Cap undercut

) (

Gas porpsity Sand inclusions

Cavity shrinkage Dendritic shrinkage Sponge shrinkage

Cracks

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Ultrasonic Testing

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Ultrasonic machining

ultrasonic cleaningUltrasonic welding

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Acoustic Spectrum

0 10 100 1K 10K 100K 1M 10M 100M

Sonic / Audible

Human

16Hz 20kHz

Ultrasonic

> 20kHz = 20,000Hz

Ultrasonic Testing

0.5MHz 50MHzUltrasonic : Sound with frequency above 20 KHz

UT

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: ): m mm(:

): Hz cps(:

): m/sec(:

fV

Velocity

Frequency

Wavelength

One cycle53

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FrequencyFrequency: Number of cycles per second

1 second

1 cycle per 1 second = 1Hertz

18 cycle per 1 second =18 Hertz

3 cycle per 1 second = 3Hertz

1 second 1 second

THE HIGHER THE FREQUENCY THE SMALLER THE WAVELENGTH

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Velocity The velocity of sound in a particular material is CONSTANTIt is the product of DENSITY and ELASTICITY of the materialIt will NOT change if frequency changes (only the wavelengthchangesExamples:

V Compression in steel : 5960 m/sV Compression in water : 1470 m/sV Compression in air : 330 m/s

STEEL WATER AIR

5 M Hz

)Longitudinal waves(

:

:

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)Transversal waves(

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)Rayleigh waves(

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)Lamb or plate waves(

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Reflected

Transmitted

Interface

VZ

reflectedZZZZ

% Sound Reflected + % Sound Transmitted = 100%

• Steel 46.7 x 106

• Water 1.48 x 106

• Air 0.0041 x 106

• Perspex 3.2 x 106

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Steel

AirSteel

Air

Steel

Steel Aluminum

Steel

Large Acoustic Impedance Ratio Large Acoustic Impedance Ratio

No Acoustic Impedance Difference Small Acoustic ImpedanceDifference

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solid metals

Substance Density(g/cm3)

Vl(m/s)

Vs(m/s)

Aluminum, rolled 2.7 6420 3040Beryllium 1.87 12890 8880Brass (70 Cu, 30 Zn) 8.6 4700 2110Copper, annealed 8.93 4760 2325Copper, rolled 8.93 5010 2270Gold, hard drawn 19.7 3240 1200Iron, Armco 7.85 5960 3240Lead, annealed 11.4 2160 700Lead, rolled 11.4 1960 690Molybdenum 10.1 6250 3350Monel metal 8.90 5350 2720Nickel 8.9 6040 3000Platinum 21.4 3260 1730Silver 10.4 3650 1610Steel, mild 7.85 5960 3235Steel, 347 Stainless 7.9 5790 3100Tin, rolled 7.3 3320 1670Titanium 4.5 6070 3125Tungsten, annealed 19.3 5220 2890

Tungsten Carbide 13.8 6655 3980Zinc, rolled 7.1 4210 2440

solid non metal

Substance Density(g/cm3)

Vl(m/s)

Vs(m/s)

Fused silica 2.2 5968 3764Glass, Pyrex 2.32 5640 3280Glass, flint 3.88 3980 2380Lucite 1.18 2680 1100Polyethylene 0.90 1950 540Polystyrene 1.06 2350 1120Resin, epoxy 1.2 2600 1100Perspex 1.18 2730 1430Polyamide 1.1 2400 1150Polyester 1.06 2350 1150Paraffin 0.83 2200

liquids

Substance Formula Density(g/cm3)

Velocity(m/s)

Acetone C3H60 0.79 1174Benzene C6H6 0.870 1295Castor oil C11H10O10 0.969 1477Chloroform CHCl3 1.49 987Ethanol amide C2H7NO 1.018 1724Ethyl ether C4H10O 0.713 985Ethylene glycol C2H6O2 1.113 1658Glycerol C3H8O3 1.26 1904Water (distilled) H2O 0.998 1496.7

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)dead zone(

)near zone(

)far zone(

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V

fDD

Df

KV

D

KSin

FZ

Distance

Intensity varies

Exponential Decay

MainBeam

Dead zone

NZ

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1 M Hz 5 M Hz

1 M Hz

5 M Hz

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5MHz 10mm:

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mmV

fD

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DfKVSine

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VVLogdB

PPLog

PPLogdB

IILogdB

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) ( )couplant(

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UT

1- 2- 3- 4- CRT5- 6- 7- 8,9- ) (

10- 11,12- ) (13,14- 15- 16- 17- 18- 19-

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)cathode ray tube) (CRT (

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)piezoelectric(

)capacitive(- )EMAT(

)laser( )magnetosctriction(

)phased arrays(

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:

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77Short pulse, 1 or 2 cycles Long pulse 12 cycles

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)normal probe, normal beam transducer(

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) T/R( )double crystal probe or transducer(

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)angle beam probe or transducer(

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: . )RT( 2 tan(RT) m/s 3230 .

CRT RT 33/2 . 35 45 60 70 80

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)skip distance(

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A

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4/5/7 step blocks

ASTM E797

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ASTM Distance AmplitudeSet of 19

ASTM E127ASTM E428

ASTM Area AmplitudeSet of 8

ASTM E127ASTM E428

ASTM Distance/Area AmplitudeSet of 10

ASTM E127ASTM E428

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V1 ) (

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V1) (

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V2 ) (

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V2 ) (

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V2

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Tandem

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