Teori Dasar Ultrasonik

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Krautkramer NDT Ultrasonic Systems

Introduction toUltrasonic Testing

SD 218

Introduction toUltrasonic Testing

SD 218© SLAMET WALUYO

PT. MULTI KHARISMA PERKASA2007

socket

matching-element

damping-block

crystalprotecting face(probe delay)

housing

workpiece Sound pulse

Straight beam probe

crystal

perspex wedge(probe delay)

damping blocks

socket

housing

workpiece Sound pulse

Angle beam probe

near field

far field

acoustical axis (central beam)

N = near field length

= angle of divergence

Sound field

Flaw detection

10 20 30 40

Flaw detection

10 20 30 40

Flaw detection

Bad flaw orientation

Improper flaw location

10 20 30 40

Angle reflection

10 20 30 40

Vertical, near surface flaw

10 155 10 155T R

Tandem technique (top)

10 155 10 155T R

Tandem technique (middle)

10 155 10 155T R

Tandem technique (bottom)

10 20 30 40

Improper flaw orientation

10 20 30 40

Perfect flaw orientation

sound beam

flat defect

reflected sound waves

Flaw detectability with improper flaw orientation

Flaw distance

start signal(pulse)

finish signal(echo)

transmitter

transit timemeasurement

work piece

sound transitpath

Stop-watch

Principle of transit time measurement

0 2 4 6 8 10

CRT / A-scan display

0 2 4 6 8 10

work piece

sound wave starts at crystal

light point

transmittertransmittertransmission

Priciple, transmission pulse

0 2 4 6 8 10

work piece

sound wave

transmittertransmitter

Priciple, sound wave in the workpiece

0 2 4 6 8 10

work piece

Priciple, sound pulse at the back wall

0 2 4 6 8 10

work piece

Priciple, sound pulse at the coupling surface

0 2 4 6 8 10

work piece

back wallecho

Priciple, echo display and 2nd run

2 4 6 8 10

protecting face

crystal

electricalzero

(initial pulse)

mechanicalzero

(surface)

Probe delay

electicalzero

(initial pulse)

mechanicalzero

(surface)sound wave

work piece

delay(wedge)

probe 0 2 4 6 8 10

Probe delay

0 2 4 6 8 10

work piece

probeback wall

flawecho

Flaw location and echo display

0 2 4 6 8 10

work piece

back wallecho

flawecho

0 2 4 6 8 10

work piece

back wallecho

flawecho

0 2 4 6 8 10

flaw echocoveredby initialpulse

work piece

back wallecho

0 2 4 6 8 10

back wallecho:

without

with flaw

work piece

0 2 4 6 8 10

flaw echosequence

work piece

0 2 4 6 8 10

dead zone

Dead zone

Near surface detectability with angle beam pobes

receiversocket

transmittersocket

damping blocks

crystal

acousticalbarrier

TR-probe / dual crystal probe

0 2 4 6 8 10

work piece

TR-probe

Probe delay with TR-probes

0 2 4 6 8 10

cross talkecho

flawecho

TR-probe

Cross talk at high gain

0 2 4 6 8 10

0 100 mm50

steel, L

Range calibration

5 10 15

Calibration block 1 with angle beam probes

5 10 15

0 2 4 6 8 10

100 mm

1st echo from circular section

5 10 15

0 2 4 6 8 10

100 mm 200 mm 300 mm

Echo sequence from 100 mm radius

s = 25 mms = 100 mms = 175 mmetc.

this wave will be absorbed !

25 mm radius of calibration block 2

s = 50 mms = 125 mms = 200 mmetc.

50 mm radius of calibration block 2

5 10 15

0 2 4 6 8 10

0 100 mmsteel

100 mm range calibration on K2

work piece reflector

0 2 4 6 8 10

s = k•R

s = sound pathk = scale factorR = screen reading

Flaw location

flaw location

Sound entry point projectionpoint

a = s•sin ßd = s•cos ß

ßß = probe angles = sound patha = surface distanced = depth

"flaw triangle"

Flaw location with angle beam probes

work piece reflector

index point -front edge of probe

a = surface distancea' = reduced surface distancex = x-value = distance:

Flaw location with angle beam probes

apparent flaw location

sd = apparent depth

Flaw location with an angle beam probe on a plate

apparent flaw location

real flaw location

d' = apparent depthd = real depthT = work piece thickness

a = s • sind‘ = s • cosd = 2T - d

Flaw location with an angle beam probe on a plate

Large defects parallel to the scanning surface

Scanning the edge of the defect

Flaw echo drops to 50% of its maximum value

0 2 4 6 8 100 2 4 6 8 10 0 2 4 6 8 10

IP BER IP BER IP BER

Flaw sizes and echo amplitudes

0 2 4 6 8 10

IP BER

Flaw distances and echo amplitudes

0 2 4 6 8 10

IP BEF

instrument gain: G = 34 dB

Defect evaluation by comparison - 1

0 2 4 6 8 10

IP BER

instrument gain: 34 dB

0 2 4 6 8 10

IP BERE

+ 8 dB

instrument gain: 42 dB

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