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Ultrasonics International 75
CONFERENCE REPORTS Ultrasonics International 75 London, UK. 24-26 March
About 300 delegates from 24 countries calne to this three-day conference: the second of the series of meetings derived from the earlier Ultrasonics for industry. Thirteen sessions covered recent advances in ultrasonics including one on ndt and another on visualisation. The session on ndt was chaired by A. A. Pollock of Dunegan-Endevco who gave a paper hinrself on acoustic enrission, D. M. Marsh of Tl Research Laboratories, UK, reported on the continuing work of his group which is attempting to predict the response o f ultrasonic pulses to defects by constructing mathematical models which are checked against schlieren visualization of pulses in glass. The models nrust take into a.ccotnlt the complex transfornrations of the ultrasound. Tire research has now been extended to a range o f defect depths and incidence angles. E. A. Lloyd of the City University, London, UK also mentioned computers when he reviewed developnrents in ultrasonic spectroscopy. He described applications of the method to quality assessment of carbonfibre reinforced plastics and of adhesive bonds as well as the more traditional problem of weld testing. The use of ndt to find the mechanical properties and structure of materials provided the subject for two reports. One of these, by G. Magistrali of Fiat, Italy, was given in place of tile advertised contribution on flaw detection by V. L. Newhouse of Purdue University, USA. Dr Magistrali discussed the methods used at the Fiat Foundry to control tire structure of cast iron. Inspectors use magnetic sorting and ultrasonics to find metallurgical defects. N. Mercier of tire National Office of Space Research, France, described work with a plastic-foil ultrasonic transducer o f 10 mm diameter to study tire structure of metals, The transducer is a broadband electrostatic foil which seems to have been discovered independently of the Harwell polymer transducer. The metallic samples under study differed only in their granularity. The changes in granularity were detected by changes in attenuation. The samples were given by the French concern SNECMA for the work and several delegates renrarked that they were not altogether suitable for this kind o f study as they seemed to be conrplex. Miss Mercier replied she had no choice in the matter, A. A. Pollock of Dunegan Endevco UK, started his discussion of acoustic emission by stating that it is its ability to locate defects which is most useful at the moment. The classification of defects is not yet a reliable possibility. Itislalk covered much recent unfamiliar work from the Ebor pressure vessel in the LISA and the KEMA pressure vessel in tire Netherhmds. In t h e K E M A w o ~ k the correlation with ultrasonic inspection was found to be good. In work with cracks around bolt holes, acoustic emission revealed cracks bett~re anv other method other than dismantling. The last contribution of the session on acoustic impact testing was written by P. A. Lloyd of Chelsea College and A. .loinson and (;. Curtis of AERE ttarwell. UK. Dr Curtis
204
delivered the paper for the others. He described a programme to evaluate the usefulness of acoustic testing, tie described the lhctors involved including the impact itself, the clamping of the testpiece, the response of transducers and the data process. Needless to say a computer proves its usefulness The author complained that variations within manufacturing tolerances severely affect the results but nonetheless frequency filters for certain shifts in frequency can allow reliable testing. Other papers at the conference had a less direct ~ellerence t~ ndt but there was much of interest ill the visualization and transducer sections. The visualization work was from British and Italian research centres. It dealt with improved imaging of ultrasound by Sokolov tubes, stereoscopy, mechanical scanning and surface waves, hr the transducer and arra~ sessions G. Curtis of AERE Harwell described tile polymeric t\/il transducers for C-scanning. Other attthors referred to rather more basic research or referred to areas other tlla~ inspeclion. In those areas of ultrasonics of interest to ndt this year'a crop of papers brought no surprises. The rise of the computer as a means of harnessing complex physical phenomeu-~ to inspection has already been in evidence for some year~. There seems to be a steady advance in ultrasonic visualiJ~ltion and in complex data evaluation. Both of these pns>lbilities will no doubt be taken up generally when tl~erc is ;~ greater knowledge of the significance of defects. Meanwhile industry will not pay a lot of money to see tire me-mingles~.
D. Brocklesbv
Measuring the thickness of coatings on metals non-destructively
Derby, UK. 30 April About 50 people came to tile Railway Technical ('entre ~lt Derby for this one-day symposiuna organised by tile NonDestructive Testing Society of Great Britain. Mr K..I. Williams. president of the NDT Society chaired the meeting throughout the day. The delegates heard descriptions ~t coating thickness gauging by all the principle methods used in commercial instruments. Three speakers discussed methods which use radiatioll {~, gauge thickness. T. Latter of Fischer Instrumentation (GB~ Ltd, outlined the use of the back-scattering of beta radiali~m for thickness measurement and then went on to describ~ modern improvements in tile technique. Current pt ~.lclicc dictates accurately prepared radioisotope sources and iev, e!rimmed apertures. Mr Latter justified tile expense of such attention to detail by pointing to the accuracy ~1 tile meth,,d in gauging metal coatings at a time of rising c~sts ,d ~lt:~i:~],
NON-DESTRUCTIVE TESTING . AUGUST 1975
About 300 delegates from 24 countries calne to this three-day conference: the second of the series of meetings derived from the earlier Ultrasonics for industry. Thirteen sessions covered recent advances in ultrasonics including one on ndt and another on visualisation. The session on ndt was chaired by A. A. Pollock of Dunegan-Endevco who gave a paper hinrself on acoustic enrission, D. M. Marsh of Tl Research Laboratories, UK, reported on the continuing work of his group which is attempting to predict the response o f ultrasonic pulses to defects by constructing mathematical models which are checked against schlieren visualization of pulses in glass. The models nrust take into a.ccotnlt the complex transfornrations of the ultrasound. Tire research has now been extended to a range o f defect depths and incidence angles. E. A. Lloyd of the City University, London, UK also mentioned computers when he reviewed developnrents in ultrasonic spectroscopy. He described applications of the method to quality assessment of carbonfibre reinforced plastics and of adhesive bonds as well as the more traditional problem of weld testing. The use of ndt to find the mechanical properties and structure of materials provided the subject for two reports. One of these, by G. Magistrali of Fiat, Italy, was given in place of tile advertised contribution on flaw detection by V. L. Newhouse of Purdue University, USA. Dr Magistrali discussed the methods used at the Fiat Foundry to control tire structure of cast iron. Inspectors use magnetic sorting and ultrasonics to find metallurgical defects. N. Mercier of tire National Office of Space Research, France, described work with a plastic-foil ultrasonic transducer o f 10 mm diameter to study tire structure of metals, The transducer is a broadband electrostatic foil which seems to have been discovered independently of the Harwell polymer transducer. The metallic samples under study differed only in their granularity. The changes in granularity were detected by changes in attenuation. The samples were given by the French concern SNECMA for the work and several delegates renrarked that they were not altogether suitable for this kind o f study as they seemed to be conrplex. Miss Mercier replied she had no choice in the matter, A. A. Pollock of Dunegan Endevco UK, started his discussion of acoustic emission by stating that it is its ability to locate defects which is most useful at the moment. The classification of defects is not yet a reliable possibility. Itislalk covered much recent unfamiliar work from the Ebor pressure vessel in the LISA and the KEMA pressure vessel in tire Netherhmds. In t h e K E M A w o ~ k the correlation with ultrasonic inspection was found to be good. In work with cracks around bolt holes, acoustic emission revealed cracks bett~re anv other method other than dismantling. The last contribution of the session on acoustic impact testing was written by P. A. Lloyd of Chelsea College and A. .loinson and (;. Curtis of AERE ttarwell. UK. Dr Curtis
204
delivered the paper for the others. He described a programme to evaluate the usefulness of acoustic testing, tie described the lhctors involved including the impact itself, the clamping of the testpiece, the response of transducers and the data process. Needless to say a computer proves its usefulness The author complained that variations within manufacturing tolerances severely affect the results but nonetheless frequency filters for certain shifts in frequency can allow reliable testing. Other papers at the conference had a less direct ~ellerence t~ ndt but there was much of interest ill the visualization and transducer sections. The visualization work was from British and Italian research centres. It dealt with improved imaging of ultrasound by Sokolov tubes, stereoscopy, mechanical scanning and surface waves, hr the transducer and arra~ sessions G. Curtis of AERE Harwell described tile polymeric t\/il transducers for C-scanning. Other attthors referred to rather more basic research or referred to areas other tlla~ inspeclion. In those areas of ultrasonics of interest to ndt this year'a crop of papers brought no surprises. The rise of the computer as a means of harnessing complex physical phenomeu-~ to inspection has already been in evidence for some year~. There seems to be a steady advance in ultrasonic visualiJ~ltion and in complex data evaluation. Both of these pns>lbilities will no doubt be taken up generally when tl~erc is ;~ greater knowledge of the significance of defects. Meanwhile industry will not pay a lot of money to see tire me-mingles~.
D. Brocklesbv
Measuring the thickness of coatings on metals non-destructively
Derby, UK. 30 April About 50 people came to tile Railway Technical ('entre ~lt Derby for this one-day symposiuna organised by tile NonDestructive Testing Society of Great Britain. Mr K..I. Williams. president of the NDT Society chaired the meeting throughout the day. The delegates heard descriptions ~t coating thickness gauging by all the principle methods used in commercial instruments. Three speakers discussed methods which use radiatioll {~, gauge thickness. T. Latter of Fischer Instrumentation (GB~ Ltd, outlined the use of the back-scattering of beta radiali~m for thickness measurement and then went on to describ~ modern improvements in tile technique. Current pt ~.lclicc dictates accurately prepared radioisotope sources and iev, e!rimmed apertures. Mr Latter justified tile expense of such attention to detail by pointing to the accuracy ~1 tile meth,,d in gauging metal coatings at a time of rising c~sts ,d ~lt:~i:~],
NON-DESTRUCTIVE TESTING . AUGUST 1975