Презентация на тему Introduction to ultrasonic testing

Krautkramer NDT Ultrasonic Systems

Introduction to
Ultrasonic Testing
SD 218

© Michael Berke
Agfa NDT GmbH, Hürth, Germany
1994 - 2002

Krautkramer NDT Ultrasonic Systems

socket

matching- element

damping- block

crystal

protecting face (probe delay)

housing

workpiece

Sound pulse

Straight beam probe

Krautkramer NDT Ultrasonic Systems

crystal

perspex wedge (probe delay)

damping blocks

socket

housing

workpiece

Sound pulse

Angle beam probe

Krautkramer NDT Ultrasonic Systems

near field

far field

acoustical axis (central beam)

N = near field length

γ = angle of divergence

3

Sound field

Krautkramer NDT Ultrasonic Systems

Flaw detection

Krautkramer NDT Ultrasonic Systems

Flaw detection

Krautkramer NDT Ultrasonic Systems

Flaw detection

Krautkramer NDT Ultrasonic Systems

Bad flaw orientation

Krautkramer NDT Ultrasonic Systems

crack

Improper flaw location

Krautkramer NDT Ultrasonic Systems

10

20

30

40

crack

Angle reflection

Krautkramer NDT Ultrasonic Systems

Angle reflection

Krautkramer NDT Ultrasonic Systems

10

20

30

40

Vertical, near surface flaw

Krautkramer NDT Ultrasonic Systems

T

R

a

1

Tandem technique (top)

Krautkramer NDT Ultrasonic Systems

T

R

a

2

Tandem technique (middle)

Krautkramer NDT Ultrasonic Systems

10

15

5

10

15

5

T

R

a

3

Tandem technique (bottom)

Krautkramer NDT Ultrasonic Systems

10

20

30

40

Improper flaw orientation

Krautkramer NDT Ultrasonic Systems

10

20

30

40

Perfect flaw orientation

Krautkramer NDT Ultrasonic Systems

sound beam

flat defect

15

10

5

reflected sound waves

Flaw detectability with improper flaw orientation

Krautkramer NDT Ultrasonic Systems

s

Flaw distance

Krautkramer NDT Ultrasonic Systems

start signal
(pulse)

finish signal
(echo)

transmitter

transit time measurement

probe

work piece

sound transit path

Stop- watch

Principle of transit time measurement

Krautkramer NDT Ultrasonic Systems

CRT / A-scan display

Krautkramer NDT Ultrasonic Systems

work piece

probe

sound wave starts at crystal

light point

transmitter

transmission pulse

Priciple, transmission pulse

Krautkramer NDT Ultrasonic Systems

work piece

probe

sound wave

transmitter

Priciple, sound wave in the workpiece

Krautkramer NDT Ultrasonic Systems

work piece

probe

transmitter

Priciple, sound pulse at the back wall

Krautkramer NDT Ultrasonic Systems

transmitter

Priciple, sound pulse at the coupling surface

Krautkramer NDT Ultrasonic Systems

transmitter

Priciple, echo display and 2nd run

Krautkramer NDT Ultrasonic Systems

2

4

6

8

10

protecting face

crystal

probe

electrical zero (initial pulse)

mechanical zero (surface)

Probe delay

Krautkramer NDT Ultrasonic Systems

electical zero (initial pulse)

mechanical zero (surface)

sound wave

work piece

delay (wedge)

probe

Probe delay

Krautkramer NDT Ultrasonic Systems

Flaw location and echo display

Krautkramer NDT Ultrasonic Systems

work piece

probe

back wall echo

flaw

flaw echo

Flaw location and echo display

Krautkramer NDT Ultrasonic Systems

work piece

probe

back wall echo

flaw

flaw echo

Flaw location and echo display

Krautkramer NDT Ultrasonic Systems

flaw echo covered by initial pulse

work piece

probe

back wall echo

flaw

Flaw location and echo display

Krautkramer NDT Ultrasonic Systems

back wall echo:

without

with flaw

work piece

probe

flaw

Flaw location and echo display

Krautkramer NDT Ultrasonic Systems

flaw echo sequence

work piece

probe

flaw

Flaw location and echo display

Krautkramer NDT Ultrasonic Systems

dead zone

Dead zone

Krautkramer NDT Ultrasonic Systems

direction of osscillation

direction of propagation

wave length

Longitudinal wave

Krautkramer NDT Ultrasonic Systems

direction of osscillation

direction of propagation

wave length

Transverse wave

Krautkramer NDT Ultrasonic Systems

Relection and refraction

Krautkramer NDT Ultrasonic Systems

10

20

30

40

L

T

possible flaw locations

Angle beam probe with both wave types

Krautkramer NDT Ultrasonic Systems

T

L

L

T

L

perspex

steel

reflected wave

refracted waves

incident wave

α = α1 = 27.5°
βT = 33.3°
βL = 90°

Longitudinal surface wave

Krautkramer NDT Ultrasonic Systems

T

L

T

perspex

steel

reflected wave

refracted transverse wave

incident wave

α = 36.4°
βT = 45°

45° transverse wave in steel

Krautkramer NDT Ultrasonic Systems

Transverse surface wave

Krautkramer NDT Ultrasonic Systems

Total reflection

Krautkramer NDT Ultrasonic Systems

27,5°

57°

33,3°

90°

perspex

steel

L

T

Ranges for incident waves

Krautkramer NDT Ultrasonic Systems

10

20

Near surface detectability with angle beam pobes

Krautkramer NDT Ultrasonic Systems

receiver socket

transmitter socket

damping blocks

crystal

delay

acoustical barrier

TR-probe / dual crystal probe

Krautkramer NDT Ultrasonic Systems

Probe delay with TR-probes

Krautkramer NDT Ultrasonic Systems

IP

BE

flaw

cross talk echo

flaw echo

TR-probe

Cross talk at high gain

Krautkramer NDT Ultrasonic Systems

0

100

mm

50

steel, L

div.

Range calibration

Krautkramer NDT Ultrasonic Systems

5

10

15

70°

45°

100 mm

60°

Calibration block 1 with angle beam probes

Krautkramer NDT Ultrasonic Systems

100 mm

1st echo from circular section

Krautkramer NDT Ultrasonic Systems

100 mm

200 mm

300 mm

Echo sequence from 100 mm radius

Krautkramer NDT Ultrasonic Systems

this wave will be absorbed !

25 mm radius of calibration block 2

Krautkramer NDT Ultrasonic Systems

50 mm radius of calibration block 2

Krautkramer NDT Ultrasonic Systems

0

100 mm steel

100 mm range calibration on K2

Krautkramer NDT Ultrasonic Systems

5

10

15

work piece

reflector

s

s = k•R

s = sound path
k = scale factor
R = screen reading

Flaw loaction

Krautkramer NDT Ultrasonic Systems

flaw location

a

s

d

Sound entry point

projection point

a = s•sin ß d = s•cos ß

ß

ß

ß = probe angle
s = sound path
a = surface distance
d = depth

"flaw triangle"

Flaw location with angle beam probes

Krautkramer NDT Ultrasonic Systems

5

10

15

work piece

reflector

a

a'

s

d

x

index point - front edge of probe

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

Flaw location with angle beam probes

Krautkramer NDT Ultrasonic Systems

5

10

15

apparent flaw location

a

s

d

= apparent depth

T

Flaw location with an angle beam probe on a plate

Krautkramer NDT Ultrasonic Systems

5

10

15

apparent flaw location

real flaw location

a

s

d

d'

d' = apparent depth
d = real depth
T = work piece thickness

T

a = s • sinβ
d‘ = s • cosβ
d = 2T - d

Flaw location with an angle beam probe on a plate

Krautkramer NDT Ultrasonic Systems

Large defects parallel to the scanning surface

Krautkramer NDT Ultrasonic Systems

Scanning the edge of the defect

Flaw echo drops to 50% of its maximum value

Krautkramer NDT Ultrasonic Systems

"half value" positions

delamination

probe position with echo amplitude reduced to 50 %

Determination of the defect area

Krautkramer NDT Ultrasonic Systems

0

2

4

6

8

10

Flaw sizes and echo amplitudes

Krautkramer NDT Ultrasonic Systems

IP

BE

R

IP

BE

R

IP

BE

R

Flaw distances and echo amplitudes

Krautkramer NDT Ultrasonic Systems

B 4 S

6 mm

4 mm

3 mm

BE

F

Distance amplitude curves on the CRT screen

Krautkramer NDT Ultrasonic Systems

IP

BE

F

F

instrument gain: G = 34 dB

80 %

Defect evaluation by comparison - 1

Krautkramer NDT Ultrasonic Systems

instrument gain: 34 dB

Defect evaluation by comparison - 2

Krautkramer NDT Ultrasonic Systems

IP

BE

RE

+ 8 dB

instrument gain: 42 dB

Defect evaluation by comparison - 3

Krautkramer NDT Ultrasonic Systems

10

20

30

40

10

20

30

40

10

20

30

40

10

20

30

40

1

1

2

2

3

3

4

4

Echo

Position

Distance amplitude curve (DAC)

Krautkramer NDT Ultrasonic Systems

time corrected gain

DAC

DAC and TCG

Krautkramer NDT Ultrasonic Systems