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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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)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
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Gas porpsity Sand inclusions
Cavity shrinkage Dendritic shrinkage Sponge shrinkage
Cracks
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Ultrasonic Testing
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:
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Ultrasonic machining
ultrasonic cleaningUltrasonic welding
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: 20000 . 0/5 25
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( : )( )(
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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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: )(:
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90 .
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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
:
5MHz 10mm:
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mmV
fD
o
DfKVSine
: )cm21(
)( . ): ( )dB B(:
.
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VVLogdB
PPLog
PPLogdB
IILogdB
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:
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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 (
) (
)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
90 ) ( .
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)angle beam probe or transducer(
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)skip distance(
)couplant(
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2.
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A
B
C
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A
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)-(
) (
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)(
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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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V1) (
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V1) (
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V1) (
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V1) (
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V1) (
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V1) (
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V2 ) (
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V2 ) (
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125
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V2
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Tandem
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...
......
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