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Transducer for ultrasonic testing of pipe
oscilloscope screen. For a defect in an internal wall a succession of attenuated echoes appears and similarly for a defect in an outer wall, by turning down the gain on the part of the screen where the initial echo appears from the external fault but conserving the gainfor an internal fault we are able to measure the latter by a series of level selecting gates (diagram given). (1100) Device for locating discontinuities by ultrasonic echo especially to find the liquid/solid interface during the continous flow Concast A. G. French Patent 1,548,870 (6 December 1968) (Applied for 12 December 1967) Transducers serving as emitter and receiver are isolated electrically and acoustically, arranged at an angle to the plane in which they are coupled to the sample by a liquid. (diagram given) (1101) Air-coupled ultrasonic probes (Lead zircomate titanate) Dean, D. S. The Journal of the Non-Destructive Testing Society of Great Britain, Vol 10, No 3 (September 1968) p 56 A 1Ocm focal length (in air) lead zirconate titanate transducer, undamped, is driven by short bursts of oscillation at its natural frequency and recurrence frequency -lOOHa. The bursts must be long enough to allow build up to a peak mechanical oscillation. Power output is much greater than single pulse excitation. Continuous transmission ,annot be used because of overheating of the transducer. 500 kHz was chosen as the best compromise frequency between flaw resolution and absorption in the specimen. Receiver bandwith was -5kHz. Transmissions through steel plates at 500°C were successful but fluctuation of signal strength due to heating of the air layer near the plates was obtained. (1102) Ultrasonic testing of melt-through welds in small-diameter thin walled tubing couplers Hagemaier, D., Posakony, G. J. Materials Evaluation,Vol xxvi,No 11 (November 1968) p 221 The paper describes various non-destructive test methods and techniques for investigating melt-through and butt-welded joints. The purpose of the ultrasonic study was to investigate the possible reliable tests for fusion welded tubing couplers of weld thickness 0.070in. Both longitudinal and shear waves are considered and the former showed to be more successful. The design and building of a 25MHz ultrasonic test unit and the effect of various weld conditions on its performance is discussed and analysed in detail. Further non-ultrasonic tests are made on the same welds and the validity of the ultrasonic ‘esting is indicated. Finally the modified search unit is described and limits to its usefulness discussed. (1103) Ultrasonic wave pulse method for test of material Kawle, K. R. W. Japanese Patent JPC 27280/68 (22 November 1968) (Applied for 12 September 1964) A pulse which is caused in a pulse device by the pulse field of electric, magnetic or electromagnetic type, is received by antennas electrostatically or inductively. The pulse is amplified by the signal and whilst the pulse is received by the pulse device an automatic supervisory device, for example a monitor, is operated by the amplified signal received from the antennas. (1104) Ultrasonic measurement of hardening depth of steel rolls. Koppelmann, J. British Iron and Steel Industry Translation 6570 (Translated from German version in Materialprafung, Vol 9, No 11 (November 1967) pp 401-405) Grain sizes can be aetermmed from ultrasonic backscattering values and a method of
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1969
moving the transceiver to average the statistical back-scattering is described. Hardened steel rolls can be measured at frequencies of 30 and 6OMHz. (1105) Transducer for ultrasonic testing of pipe Kortenhoven, P. US Patent 3,413,843 (3 December 1968) (Filed 6 October 1965) The apparatus for testing elongated objects includes an ultrasonic piezoelectric crystal mounted on a carriage and a means for supportmg the carriage on the specimen to be tested. Normally the crystal is surrounded by a rubber boat, which is filled with a liquid to reduce the impedance mismatch between crystal and the specimen. Various means are provided to adjust the position of the crystal with respect to the surface of the article to be inspected. (1106) Ultrasonic theory applied to automatic inspection of welds Lovelace, J. F., Luini, L. A. Materials Evaluation, Vol xxvi, No 10 (October 1968) p 204 Factors effecting the success of angle-beam ultrasonic testing are discussed in detail. These include the beam pattern of the transducer behaviour. Accuracy and resolution limits are mentioned and also the averaging effect of the transducer. There is particular reference to the transmitting properties of probe-to-weldment interfaces and its effect on the sensitivity of particular experiments, with practical advice on the interpretation of tests. The theory is then used to design an automatic inspection system, details of which are given along with tests of a prototype. (1107) Apparatus for measuring the mass per unit area of sheet material Nils Bertil Agdur, Weissglas, P. British Patent 1,139,142 (Applied for 1966) (Sweden 1965) Published 1969 This paper describes an acoustic method for measuring the mass per unit area of sheet material such as paper. Pulses of sound of frequency 15kHz are caused to impinge on the surface of the material under test, the force being applied at right-angles to the plane of the material. The amplitude of vibration of the material is detected by various means and if a relation is established between the mass/unit area of the material under test and the receiver amplitude, it is possible to continuously sample this parameter. Various arrangements for the detection of the amplitude of vibratio.1 of the material under test. (1108) System for locating underwater objects Salathiel, R. A. US Patent 3,409,868 (5 November 1968) (Filed 10 March 19671 Underwater well heads and other submerged facilities are located and identified by transmitting acoustic impulses into the water and detecting distinctive pulses returned by reflectors mounted adjacent to these facilities. (1109) A study of the behaviour of plastically deformed carbon steel by means of ultrasonic attenuation Saivaragi , Y., et al British Iron and Steel Industry Translation 6832 (Translation from Japanese version in Journal of Society of Materials Science, Japan,Vol 17 (March 1968) pp 219-225) Steels SlOC,S2OC,S3OC and S4OC were used and attenuation was related to plastic deformation and annealing temperatures. Movement of a dislocation line is the mechanism assumed and internal stress is related to magnetomechanical losses associated with micro-eddy currents induced by vibration of magnetic domain walls. (1110)
Implications of the attenuation-produced pulse distortion upon the ultrasonic method of NDT Serabian. S. Materials Evaluation, Vol xxvi, No 9 (September 1968) p 173 Distortion produced by attenuation of the amplitude-frequency content of an ultrasonic pulse in nondispersive materials is investigated with respect to degradation of flaw detecting ability and to measurement of velocity and attenuation. Experimental evidence is presented of such distortion and the requirements for its production. Detecting ability is shown to suffer as only lower frequencies in the pulse are effective, and so resolving power and sensitivity also suffer. The problems in measuring velocity and attenuation are shown to be lack of uniqueness of the testing pulse due to the distortion. Some techniques and apparatus for rorrective actions are given. (1111) On-stream ultrasonic examination in the oil industry Wilkinson, L. The Journal of the Non-Destructive Testing Society of Great Britain, Vol 10. No 3 (September 1968) pp 57-58 Using presently available equipment and applying known corrections, the accuracies that can be expected when measuring metal thickness under field conditions are; Temperature
ambient up to 200°C * 0. 151n
200” ~ 350°C
i 0. 021n
350°C up + 0. 025111 When using heat barrier couplants, corrections for calibration on a cold test piece must be made. These are negligible when free water cooling and couplants are used. Ceramic transducers with heat resistant plastic Inserts are subject to errors due to heating of the plastic. Typical curves are given for various contact periods and temperatures. The relation between transducer heating and contact time is not linear, large corrections being necessary at higher temperatures. This suggests the use of short contact times at high temperatures. (1112) Acoustic leak detecting apparatus (Pertains to apparatus for passing through a pressurized pipeline and acoustically detecting leaks) Wood, F. M. US Patent 3,413,653 (26 November 1968) (Filed 25 July 196’7) The apparatus is used for acoustically detecting leaks in a pressurized pipeline, through which it can be passed. One transducer on the upstream side of a pipeline pg, and one transducer on the downstream side. are connected to the circuitry which includes suitable filters for filtering out environmental low frequencies, a differential amplifier for cancelling the background noise not filtered out from the detected leak noise, and a multi-channel recording system. By means of this system the output of the differential amplifier and one or both of the separate channel signals may be recorded. In additiu.1, a magnetic responsive device may be included for detecting and recording magnetic field responses. (1113) Research on correlations between structural characteristics of silicon-aluminous refractories and ultra-sound Aliprandi, G., Ratto, A., Savioli, F. Metallurgica Italiana, Vol 60, No 4 (April 1968) (Proceedings of the 5th Seminar on Nondestructive Testing, Sirmione, March 1967) pp 331-333 (In Italian) (1114) Recommended ultrasonic practice for evaluating wrought steel products for aerospace application. (Interim draft) American Society for NDT Aerospace Committee Report No 3 Materials Evaluation, Vol xxvi,No 9 (September 1968) p 18A (1116)
144
ULTRASONICS
April
1969
moving the transceiver to average the statistical back-scattering is described. Hardened steel rolls can be measured at frequencies of 30 and 6OMHz. (1105) Transducer for ultrasonic testing of pipe Kortenhoven, P. US Patent 3,413,843 (3 December 1968) (Filed 6 October 1965) The apparatus for testing elongated objects includes an ultrasonic piezoelectric crystal mounted on a carriage and a means for supportmg the carriage on the specimen to be tested. Normally the crystal is surrounded by a rubber boat, which is filled with a liquid to reduce the impedance mismatch between crystal and the specimen. Various means are provided to adjust the position of the crystal with respect to the surface of the article to be inspected. (1106) Ultrasonic theory applied to automatic inspection of welds Lovelace, J. F., Luini, L. A. Materials Evaluation, Vol xxvi, No 10 (October 1968) p 204 Factors effecting the success of angle-beam ultrasonic testing are discussed in detail. These include the beam pattern of the transducer behaviour. Accuracy and resolution limits are mentioned and also the averaging effect of the transducer. There is particular reference to the transmitting properties of probe-to-weldment interfaces and its effect on the sensitivity of particular experiments, with practical advice on the interpretation of tests. The theory is then used to design an automatic inspection system, details of which are given along with tests of a prototype. (1107) Apparatus for measuring the mass per unit area of sheet material Nils Bertil Agdur, Weissglas, P. British Patent 1,139,142 (Applied for 1966) (Sweden 1965) Published 1969 This paper describes an acoustic method for measuring the mass per unit area of sheet material such as paper. Pulses of sound of frequency 15kHz are caused to impinge on the surface of the material under test, the force being applied at right-angles to the plane of the material. The amplitude of vibration of the material is detected by various means and if a relation is established between the mass/unit area of the material under test and the receiver amplitude, it is possible to continuously sample this parameter. Various arrangements for the detection of the amplitude of vibratio.1 of the material under test. (1108) System for locating underwater objects Salathiel, R. A. US Patent 3,409,868 (5 November 1968) (Filed 10 March 19671 Underwater well heads and other submerged facilities are located and identified by transmitting acoustic impulses into the water and detecting distinctive pulses returned by reflectors mounted adjacent to these facilities. (1109) A study of the behaviour of plastically deformed carbon steel by means of ultrasonic attenuation Saivaragi , Y., et al British Iron and Steel Industry Translation 6832 (Translation from Japanese version in Journal of Society of Materials Science, Japan,Vol 17 (March 1968) pp 219-225) Steels SlOC,S2OC,S3OC and S4OC were used and attenuation was related to plastic deformation and annealing temperatures. Movement of a dislocation line is the mechanism assumed and internal stress is related to magnetomechanical losses associated with micro-eddy currents induced by vibration of magnetic domain walls. (1110)
Implications of the attenuation-produced pulse distortion upon the ultrasonic method of NDT Serabian. S. Materials Evaluation, Vol xxvi, No 9 (September 1968) p 173 Distortion produced by attenuation of the amplitude-frequency content of an ultrasonic pulse in nondispersive materials is investigated with respect to degradation of flaw detecting ability and to measurement of velocity and attenuation. Experimental evidence is presented of such distortion and the requirements for its production. Detecting ability is shown to suffer as only lower frequencies in the pulse are effective, and so resolving power and sensitivity also suffer. The problems in measuring velocity and attenuation are shown to be lack of uniqueness of the testing pulse due to the distortion. Some techniques and apparatus for rorrective actions are given. (1111) On-stream ultrasonic examination in the oil industry Wilkinson, L. The Journal of the Non-Destructive Testing Society of Great Britain, Vol 10. No 3 (September 1968) pp 57-58 Using presently available equipment and applying known corrections, the accuracies that can be expected when measuring metal thickness under field conditions are; Temperature
ambient up to 200°C * 0. 151n
200” ~ 350°C
i 0. 021n
350°C up + 0. 025111 When using heat barrier couplants, corrections for calibration on a cold test piece must be made. These are negligible when free water cooling and couplants are used. Ceramic transducers with heat resistant plastic Inserts are subject to errors due to heating of the plastic. Typical curves are given for various contact periods and temperatures. The relation between transducer heating and contact time is not linear, large corrections being necessary at higher temperatures. This suggests the use of short contact times at high temperatures. (1112) Acoustic leak detecting apparatus (Pertains to apparatus for passing through a pressurized pipeline and acoustically detecting leaks) Wood, F. M. US Patent 3,413,653 (26 November 1968) (Filed 25 July 196’7) The apparatus is used for acoustically detecting leaks in a pressurized pipeline, through which it can be passed. One transducer on the upstream side of a pipeline pg, and one transducer on the downstream side. are connected to the circuitry which includes suitable filters for filtering out environmental low frequencies, a differential amplifier for cancelling the background noise not filtered out from the detected leak noise, and a multi-channel recording system. By means of this system the output of the differential amplifier and one or both of the separate channel signals may be recorded. In additiu.1, a magnetic responsive device may be included for detecting and recording magnetic field responses. (1113) Research on correlations between structural characteristics of silicon-aluminous refractories and ultra-sound Aliprandi, G., Ratto, A., Savioli, F. Metallurgica Italiana, Vol 60, No 4 (April 1968) (Proceedings of the 5th Seminar on Nondestructive Testing, Sirmione, March 1967) pp 331-333 (In Italian) (1114) Recommended ultrasonic practice for evaluating wrought steel products for aerospace application. (Interim draft) American Society for NDT Aerospace Committee Report No 3 Materials Evaluation, Vol xxvi,No 9 (September 1968) p 18A (1116)