GB2151786A - Ultrasonic flaw detection - Google Patents

Ultrasonic flaw detection Download PDF

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Publication number
GB2151786A
GB2151786A GB08429825A GB8429825A GB2151786A GB 2151786 A GB2151786 A GB 2151786A GB 08429825 A GB08429825 A GB 08429825A GB 8429825 A GB8429825 A GB 8429825A GB 2151786 A GB2151786 A GB 2151786A
Authority
GB
United Kingdom
Prior art keywords
probe
signal
ultrasound
flaws
flaw
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08429825A
Other versions
GB8429825D0 (en
Inventor
Thomas Harry Sargent
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UK Atomic Energy Authority
Original Assignee
UK Atomic Energy Authority
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by UK Atomic Energy Authority filed Critical UK Atomic Energy Authority
Publication of GB8429825D0 publication Critical patent/GB8429825D0/en
Publication of GB2151786A publication Critical patent/GB2151786A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/06—Visualisation of the interior, e.g. acoustic microscopy
    • G01N29/0609—Display arrangements, e.g. colour displays
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/24—Probes
    • G01N29/2487—Directing probes, e.g. angle probes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0422—Shear waves, transverse waves, horizontally polarised waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/044—Internal reflections (echoes), e.g. on walls or defects
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/056—Angular incidence, angular propagation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/10—Number of transducers
    • G01N2291/102—Number of transducers one emitter, one receiver

Abstract

Flaws (12, 13), not readily detectable by pulsed ultrasound because of their location or orientation, are detected audibly by demodulating the pulse frequency of the ultrasound. A first shear wave probe (14) operating in the pulse/echo mode has located at a distance (d) behind it a second receiving probe (17). The first probe processes (15, 16) received signals using conventional ultrasonic techniques. The second probe, with a wider reception angle, demodulates (18) received signals to give an audio output (19). <IMAGE>

Description

SPECIFICATION Ultrasonic flaw detection This invention relates to ultrasonic flaw detection and is concerned with the problem of failure, with known apparatus, to detect flaws such as may arise because the flaw has an unfavourable orientation or is located too near the surface of the specimen being tested.
According to the present invention there is provided apparatus for ultrasonically detecting flaws in a body to be inspected, said apparatus comprising a first probe for generating ultrasonic energy, means for driving the first probe with a high frequency signal modulated with a low frequency signal, a second probe located in spaced relation to the first probe and arranged to receive acoustic energy derived from the first probe as a result of scattering of the transmitted signal by defects in the body, means for demodulating the received signal to retrieve said low frequency signal, and signalling means operable by the demodulated low frequency signal.
One embodiment of the invention comprises an ultrasonic flaw detector which has associated with it at least a pair of probes, one of which transmits ultrasound and receives flaw-reflected pulsed ultrasound which can then be processed in known manner to give ultrasonic flaw detection, and the other receives flaw-reflected pulsed ultrasound and processes it in a radio receiver tuned to the ultrasound frequency with demodulation of the ultrasound to give a signal, such as an audio signal, derived from the pulse rate frequency.
The invention will now be described further, by way of example, with reference to the accompanying single figure drawing which is a sectional elevation of a piece of flawed material under test.
Test material 10 is assumed to have a flaw 11 in the body of the material and a flaw 12 near the surface of the material. Line 13 represents the path of transmitted and received narrow ultrasound beam (2-4 MHz) pulsed at an audio frequency.
The ultrasound is derived from an angled shearwave probe 14 operating in the pulse echo mode having a detector 15 processing ultrasound received back from flaws in the material to give ultrasonic flaw detection in the known manner such as at an oscilloscope 16.
A second similar angled shear wave probe 17 (having the same operating frequency as probe 14 but differing from probe 14 in that it has a wider reception angle and operates as a receiver of the audio pulsed ultrasound scattered back from flaws hit by ultrasound transmitted by probe 14 as shown by lines 13a) is located behind the probe 14 and spaced at a distance d from the probe 14.
Probe 17 has the same or a multiple of the operational frequency of probe 14 and is connected to the input of a radio receiver 18 tuned to the ultrasound frequency or a multiple of the frequencies and including a demodulator so that the pulse rate of the ultrasound appears as an audio signal at a loudspeaker, earphone, or recorder output 19 of the receiver.
Most flaws (such as those represented by flaw 11) will give rise to a detectable signal at detector 15 and receiver 18. However, in the case of certain flaws (such as those represented by flaw 12 and vertical flaws) an identifiable ultrasonic signal will not be received at detector 15 but an identifiable sound signal will be received at receiver 18, with its sharply tuned circuits. Such flaws can then be made the subject of special ultrasonic investigation using alternative techniques in which their location, size and orientation can be better resolved.
The distance d is not critical. With test material 10 of 100 mm thickness the probe 17 could be placed in the range of 150 to 300 mm behind probe 14.
Bonus advantages may arise from the invention such as the reduction in the number of probes required with ultrasonic detectors and the probability of reducing overall cost of flaw detection equipment.
Circuitry in the receiver 18 could be used to drive the transmitting probe 14.
1. Apparatus for ultrasonically detecting flaws in a body to be inspected, said apparatus comprising a first probe for generating ultrasonic energy, means for driving the first probe with a high frequency signal modulated with a low frequency sig nal, a second probe located in spaced relation to the first probe and arranged to receive acoustic energy derived from the first probe as a result of scattering of the transmitted signal by defects in the body, means for demodulating the received signal to retrieve said low frequency signal, and signalling means operable by the demodulated low frequency signal.
2. Apparatus as claimed in Claim I in which high frequency signal is pulsed and the pulse repetition rate constitutes said low frequency signal.
3. Apparatus as claimed in Claim 1 or 2 in which the first probe also functions as a receiving probe.
4. Apparatus as claimed in Claim 3 in which the first probe is coupled to a flaw detector for processing and displaying the output from said first probe.
5. Apparatus as claimed in any one of Claims 14 in which said low frequency signal is within the audio range and the signalling device is driven by the demodulated signal to provide an audible output.
6. Apparatus as claimed in any one of Claims 15 in which both probes are angled shear-wave probes.
7. Apparatus as claimed in any one of Claims 16 in which the second probe has a wider reception angle than the first probe.
8. Apparatus for ultrasonically detecting flaws in a body, said apparatus being substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.
9. A method of ultrasonic testing comprising
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Ultrasonic flaw detection This invention relates to ultrasonic flaw detection and is concerned with the problem of failure, with known apparatus, to detect flaws such as may arise because the flaw has an unfavourable orientation or is located too near the surface of the specimen being tested. According to the present invention there is provided apparatus for ultrasonically detecting flaws in a body to be inspected, said apparatus comprising a first probe for generating ultrasonic energy, means for driving the first probe with a high frequency signal modulated with a low frequency signal, a second probe located in spaced relation to the first probe and arranged to receive acoustic energy derived from the first probe as a result of scattering of the transmitted signal by defects in the body, means for demodulating the received signal to retrieve said low frequency signal, and signalling means operable by the demodulated low frequency signal. One embodiment of the invention comprises an ultrasonic flaw detector which has associated with it at least a pair of probes, one of which transmits ultrasound and receives flaw-reflected pulsed ultrasound which can then be processed in known manner to give ultrasonic flaw detection, and the other receives flaw-reflected pulsed ultrasound and processes it in a radio receiver tuned to the ultrasound frequency with demodulation of the ultrasound to give a signal, such as an audio signal, derived from the pulse rate frequency. The invention will now be described further, by way of example, with reference to the accompanying single figure drawing which is a sectional elevation of a piece of flawed material under test. Test material 10 is assumed to have a flaw 11 in the body of the material and a flaw 12 near the surface of the material. Line 13 represents the path of transmitted and received narrow ultrasound beam (2-4 MHz) pulsed at an audio frequency. The ultrasound is derived from an angled shearwave probe 14 operating in the pulse echo mode having a detector 15 processing ultrasound received back from flaws in the material to give ultrasonic flaw detection in the known manner such as at an oscilloscope 16. A second similar angled shear wave probe 17 (having the same operating frequency as probe 14 but differing from probe 14 in that it has a wider reception angle and operates as a receiver of the audio pulsed ultrasound scattered back from flaws hit by ultrasound transmitted by probe 14 as shown by lines 13a) is located behind the probe 14 and spaced at a distance d from the probe 14. Probe 17 has the same or a multiple of the operational frequency of probe 14 and is connected to the input of a radio receiver 18 tuned to the ultrasound frequency or a multiple of the frequencies and including a demodulator so that the pulse rate of the ultrasound appears as an audio signal at a loudspeaker, earphone, or recorder output 19 of the receiver. Most flaws (such as those represented by flaw 11) will give rise to a detectable signal at detector 15 and receiver 18. However, in the case of certain flaws (such as those represented by flaw 12 and vertical flaws) an identifiable ultrasonic signal will not be received at detector 15 but an identifiable sound signal will be received at receiver 18, with its sharply tuned circuits. Such flaws can then be made the subject of special ultrasonic investigation using alternative techniques in which their location, size and orientation can be better resolved. The distance d is not critical. With test material 10 of 100 mm thickness the probe 17 could be placed in the range of 150 to 300 mm behind probe 14. Bonus advantages may arise from the invention such as the reduction in the number of probes required with ultrasonic detectors and the probability of reducing overall cost of flaw detection equipment. Circuitry in the receiver 18 could be used to drive the transmitting probe 14. CLAIMS
1. Apparatus for ultrasonically detecting flaws in a body to be inspected, said apparatus comprising a first probe for generating ultrasonic energy, means for driving the first probe with a high frequency signal modulated with a low frequency sig nal, a second probe located in spaced relation to the first probe and arranged to receive acoustic energy derived from the first probe as a result of scattering of the transmitted signal by defects in the body, means for demodulating the received signal to retrieve said low frequency signal, and signalling means operable by the demodulated low frequency signal.
2. Apparatus as claimed in Claim I in which high frequency signal is pulsed and the pulse repetition rate constitutes said low frequency signal.
3. Apparatus as claimed in Claim 1 or 2 in which the first probe also functions as a receiving probe.
4. Apparatus as claimed in Claim 3 in which the first probe is coupled to a flaw detector for processing and displaying the output from said first probe.
5. Apparatus as claimed in any one of Claims 14 in which said low frequency signal is within the audio range and the signalling device is driven by the demodulated signal to provide an audible output.
6. Apparatus as claimed in any one of Claims 15 in which both probes are angled shear-wave probes.
7. Apparatus as claimed in any one of Claims 16 in which the second probe has a wider reception angle than the first probe.
8. Apparatus for ultrasonically detecting flaws in a body, said apparatus being substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.
9. A method of ultrasonic testing comprising coupling ultrasound into a body to be inspected, the ultrasound being derived from a first probe driven by a high frequency electrical signal modulated with a lower frequency signal, locating a second probe on the body in spaced relation to the first probe so that any defect is differently orientated with respect to the two probes, the second probe being arranged to receive acoustic energy scattered from any defect present, demodulating the electrical output of the second probe to derive said low frequency signal and using the demodulated signal to drive a signalling device.
10. A method as claimed in Claim 9 in which the signalling device provides an audible output when energised with said demodulated signal.
11. A method of ultrasonic testing substantially as hereinbefore described with reference to the accompanying drawing.
GB08429825A 1983-12-19 1984-11-26 Ultrasonic flaw detection Withdrawn GB2151786A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB838333796A GB8333796D0 (en) 1983-12-19 1983-12-19 Ultrasonic flaw detection

Publications (2)

Publication Number Publication Date
GB8429825D0 GB8429825D0 (en) 1985-01-03
GB2151786A true GB2151786A (en) 1985-07-24

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GB838333796A Pending GB8333796D0 (en) 1983-12-19 1983-12-19 Ultrasonic flaw detection
GB08429825A Withdrawn GB2151786A (en) 1983-12-19 1984-11-26 Ultrasonic flaw detection

Family Applications Before (1)

Application Number Title Priority Date Filing Date
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989011651A1 (en) * 1988-05-20 1989-11-30 Moskovskoe Vysshee Tekhnicheskoe Uchilische Imeni Method for ultrasonically checking weld seams of articles
GB2292610A (en) * 1994-08-24 1996-02-28 British Aerospace Crack detection in a sheet of material around a fastener hole

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB683592A (en) * 1950-12-01 1952-12-03 Sperry Prod Inc Improvements in or relating to device for inspecting objects by means of vibration waves
GB699796A (en) * 1950-03-24 1953-11-18 Parsons & Marine Eng Turbine Improvements in or relating to the detection of cracks in engineering components
GB843532A (en) * 1955-07-18 1960-08-04 Electrocircuits Inc Improvements in or relating to method and apparatus for measuring wave propagation time
GB1549667A (en) * 1975-04-24 1979-08-08 Krautkramer Branson Ultrasonic test method and apparatus
GB2022827A (en) * 1978-06-06 1979-12-19 Panametrics Method and apparatus for examining a solid using acoustic waves
GB2034035A (en) * 1978-08-11 1980-05-29 Mannesmann Ag Ultrasonic testing of weld seams
GB2058350A (en) * 1979-09-07 1981-04-08 Mannesmann Ag Ultrasonic testing of sheet metal

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB699796A (en) * 1950-03-24 1953-11-18 Parsons & Marine Eng Turbine Improvements in or relating to the detection of cracks in engineering components
GB683592A (en) * 1950-12-01 1952-12-03 Sperry Prod Inc Improvements in or relating to device for inspecting objects by means of vibration waves
GB843532A (en) * 1955-07-18 1960-08-04 Electrocircuits Inc Improvements in or relating to method and apparatus for measuring wave propagation time
GB1549667A (en) * 1975-04-24 1979-08-08 Krautkramer Branson Ultrasonic test method and apparatus
GB2022827A (en) * 1978-06-06 1979-12-19 Panametrics Method and apparatus for examining a solid using acoustic waves
GB2034035A (en) * 1978-08-11 1980-05-29 Mannesmann Ag Ultrasonic testing of weld seams
GB2058350A (en) * 1979-09-07 1981-04-08 Mannesmann Ag Ultrasonic testing of sheet metal

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
B BANKS, G E OLDFIELD, H RAWDING, }ULTRASONIC FLOW DETECTION IN METALS}, 1962, ILIFFE PAGE 164. *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989011651A1 (en) * 1988-05-20 1989-11-30 Moskovskoe Vysshee Tekhnicheskoe Uchilische Imeni Method for ultrasonically checking weld seams of articles
EP0382844A1 (en) * 1988-05-20 1990-08-22 Moskovskoe Vysshee Tekhnicheskoe Uchilische Imeni N.E.Baumana Method for ultrasonically checking weld seams of articles
EP0382844A4 (en) * 1988-05-20 1991-03-20 Moskovskoe Vysshee Tekhnicheskoe Uchilische Imeni N.E.Baumana Method for ultrasonically checking weld seams of articles
US5060518A (en) * 1988-05-20 1991-10-29 Moskovskoe Vysshee Tekhnicheskoe Uchilische Imeni N.E. Baumana Method of ultrasonic inspection of welds of articles
GB2292610A (en) * 1994-08-24 1996-02-28 British Aerospace Crack detection in a sheet of material around a fastener hole
GB2292610B (en) * 1994-08-24 1998-08-05 British Aerospace Method for crack detection in a sheet of material around a fastener hole

Also Published As

Publication number Publication date
GB8333796D0 (en) 1984-01-25
GB8429825D0 (en) 1985-01-03

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)