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Ultrasonic determination of texture and residual stress in polycrystalline metals
ND T Abstracts Delsanto, P.P.; Mignogna, R.B.; Clark, A.V. Jr.; Mitrakovic, D.; Moulder, J.C. 38078
Most ultrasonic stress measurement techniques measure some combination of stresses, such as the sum or difference of principal stresses, relative to some (possibly unknown) stress state. In order to apply fracture mechanics methods m assessment of flawed structures, stresses must he determined absolutely. Ultrasonic stress measurement methods rely on the acoustoelastic effect: the stress-induced change in phase velocity. Unfortunately, texture also has a comparable effect. This has limited most applications to measurement of applied (as opposed to residual) stress.
Acoustoelastic determination of residual stresses Residual Stresses in Science and Technology. Proceedings o f the International Conference, Garmisch-Partenkirchen (FRG), Oct. 1986. pp. 175-182. Deutsche Gesellschaft fur Metallkunde, 1059 pp. (1987) The general perturbative formalism for the propagation of Rayleigh wave on the surface of initially ,deformed anisolropic material plates is applied to the particular case of an orthotropic distribution of cubic crystallites. Applied and residual stresses can he determined from their correlation with the measured Rayleigh wave propagation velocity. A critical problem, especially in the case of residual stresses, is the separation of texture and acoustoelastic effect;. Two techniques for the solution of this problem are proposed and their range of validity is discussed. 37340
36814
Analytical Ultrasonics in Materials Research and Testing. Proceedings of a conference, NASA Lewis Research Center, Ohio (United States), 13- 14 Nov. 1984. pp. 61-74. NASA Conference Publication 2383 (1986). External dc magnetic field-induced changes in natural velocity of Rayleigh surface waves have been measured in steel specimens under various stress conditions. The low field slopes of curves representing the fractional changes of natural velocity have been proved to provide correct stress information in steels with different metallurgical properties. The slopes of curves under uniaxial compression, exceeding about one third of the yield stress, fall below zero in all the specimens when magnetized along the stress axis. The slopes under tension vary among different steels but remain positive in any circumstances. The stress effect is observed for both applied and residual stress. A physical interpretation of these results is given based on the stress-induced domain structure changes and the AE- effect. Most importantly, it is found that the influence of detailed metallurgical properties causes only secondary effects on the obtained stress information.
Sayers, C.M.
Ultrasonic determination of texture and residual stress in polycrystalline metals Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United Stales), 18-20 Sep. 1985. pp. 319-336. Martinus Nijhoff Publishers (1!)87) In a polycrystalline aggregate the elastic constants in the specimen reference frame vary from grain to grain due to the random orientation of the grains. Polycrystalline metals are therefore elastically inhomogeneous, and the elastic constant mismatch at the grain boundaries leads to scattering of the ultrasonic wave. In the long wavelength limit, however, the metal can be modelled as an elastic continuum with elastic constants determined by the elastic constants of the grains and the crystallite orientation distribution function (CODF). This function gives the probability of a crystallite having a given orientation with respect to the specimen frame, and gives a quantitative description of the texture, or crystallographic alignment, of the material. In a strongly l~xtured metal the yield stress varies as a function of direction and this can lead to non-uniform flow in deep drawing for example. As a result there is a need for a non- destructive measurement of texture in process control, and there is considerable interest in the use of ultrasonics for this purpose. Information on the CODF can he obtained from ultrasonic velocity measurements.
36515 Swanson, G.D. Investigation of ultrasonic methods measurement in metals
for residual stress
Allied Corporation, Bendix Kansas City Division, Missouri (United States), BDX-613-3685, 18pp. (Feb. 1987) Investigation was continued on three ultrasonic methods and one combination of methods for the nondestructive measurement of residual stress in metal parts. Experiments were designed and transducers were modified such that all measurements could be made using only single surface contact to a flat area no larger than 25 m m square. Transducer adaptability for use on curved surfaces was also considered to be important.
37339 Fukuoka, H. Ultrasonic measurement of residual stress Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United States), 18-20 Sep. 1985. pp. 275-300. Martinus Nijhoff Publishers ( ! !)87) The main point of this paper is a practical application of acoustoelastic measurement of residual stress in industry. 37338
Heyman, J.S.; Namkung, M.
Residual stress measurements in carbon steel
36505
Pritchard, S.E.
The use of ultrasonics for residual stress analysis NDT International, Vol. 20, No. I, pp. 57-60 (Feb 1987) A 'critical size' defect, as defined in fracture mechanics calculations, is influenced by the fracture toughness and microstructure of the material in the vicinity of the crack and also by the level of local stress assisting or impeding crack development. It has been realized at the National NDT Centre for some time that a balanced assessment of crack significance requires not only detailed information on crack location, crack dimensions and crack nature, but also quantitative data on microstructural variations and on levels of residual stress. The present paper discusses Harwelrs programme in recent years to develop an ultrasonic technique to assess residual stress.
Clark, A.V.; Moulder, J.C., Mignogna, R.B.; DelSanto,
P.P. A comparison of several ultrasonic techniques for absolute stress determination in the presence of texture Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United Stales), 18-20 Sep. 1985. pp. 345-360. Martinus Nijhoff Publishers (1987)
Each entry in NDT Abstracts consists of the serial number in the National NDT Centre Information Store for identification purposes; the title of the paper, book or report; the name of the author; the name of the source journal or document and the abstracts. Where necessary, author's names and the title of foreign j ournals have been transliterated into the Latin alphabet according to British Standard BS 2979:1958.
Information Service. US Department of Commerce, Springfield, Virginia 22151, USA. British and foreign standards can be obtained from Sales Department, British Standards Institution, 101 Pentonville Road, London NI 9ND; and British and foreign patents from the Patents Office Sales Branch, Block C, Station Square House, St Mary Cray, Orpington, Kent BR5 3RD.
Availability of Publications
Information-retrievalService
Most papers listed may be obtained as loans or copies via local library or direct from Loans Department, British Library Document Supply Centre, Boston Spa, Wetherby, Yorkshire LS23 7BQ. Details of the British Lending Library's UK and International Services may be obtained from The Director, BritzLshLibrary Lending Division. Technical reports are also available from the Loans Department of the British Lending Library and in the USA from the National Technical
All entries are indexed in a computerized retrieval system, located at Harwell, which allows rapid searching of information relevant to any particular inspection problem. This service is available to both UK and overseas organizations through the National NDT Centre's Qualtis Subscription Scheme - further details are available from Phil Lawrence on Abingdon (0235) 433391. :~ 1994 United Kingdom Atomic Energy Authority
121
Most ultrasonic stress measurement techniques measure some combination of stresses, such as the sum or difference of principal stresses, relative to some (possibly unknown) stress state. In order to apply fracture mechanics methods m assessment of flawed structures, stresses must he determined absolutely. Ultrasonic stress measurement methods rely on the acoustoelastic effect: the stress-induced change in phase velocity. Unfortunately, texture also has a comparable effect. This has limited most applications to measurement of applied (as opposed to residual) stress.
Acoustoelastic determination of residual stresses Residual Stresses in Science and Technology. Proceedings o f the International Conference, Garmisch-Partenkirchen (FRG), Oct. 1986. pp. 175-182. Deutsche Gesellschaft fur Metallkunde, 1059 pp. (1987) The general perturbative formalism for the propagation of Rayleigh wave on the surface of initially ,deformed anisolropic material plates is applied to the particular case of an orthotropic distribution of cubic crystallites. Applied and residual stresses can he determined from their correlation with the measured Rayleigh wave propagation velocity. A critical problem, especially in the case of residual stresses, is the separation of texture and acoustoelastic effect;. Two techniques for the solution of this problem are proposed and their range of validity is discussed. 37340
36814
Analytical Ultrasonics in Materials Research and Testing. Proceedings of a conference, NASA Lewis Research Center, Ohio (United States), 13- 14 Nov. 1984. pp. 61-74. NASA Conference Publication 2383 (1986). External dc magnetic field-induced changes in natural velocity of Rayleigh surface waves have been measured in steel specimens under various stress conditions. The low field slopes of curves representing the fractional changes of natural velocity have been proved to provide correct stress information in steels with different metallurgical properties. The slopes of curves under uniaxial compression, exceeding about one third of the yield stress, fall below zero in all the specimens when magnetized along the stress axis. The slopes under tension vary among different steels but remain positive in any circumstances. The stress effect is observed for both applied and residual stress. A physical interpretation of these results is given based on the stress-induced domain structure changes and the AE- effect. Most importantly, it is found that the influence of detailed metallurgical properties causes only secondary effects on the obtained stress information.
Sayers, C.M.
Ultrasonic determination of texture and residual stress in polycrystalline metals Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United Stales), 18-20 Sep. 1985. pp. 319-336. Martinus Nijhoff Publishers (1!)87) In a polycrystalline aggregate the elastic constants in the specimen reference frame vary from grain to grain due to the random orientation of the grains. Polycrystalline metals are therefore elastically inhomogeneous, and the elastic constant mismatch at the grain boundaries leads to scattering of the ultrasonic wave. In the long wavelength limit, however, the metal can be modelled as an elastic continuum with elastic constants determined by the elastic constants of the grains and the crystallite orientation distribution function (CODF). This function gives the probability of a crystallite having a given orientation with respect to the specimen frame, and gives a quantitative description of the texture, or crystallographic alignment, of the material. In a strongly l~xtured metal the yield stress varies as a function of direction and this can lead to non-uniform flow in deep drawing for example. As a result there is a need for a non- destructive measurement of texture in process control, and there is considerable interest in the use of ultrasonics for this purpose. Information on the CODF can he obtained from ultrasonic velocity measurements.
36515 Swanson, G.D. Investigation of ultrasonic methods measurement in metals
for residual stress
Allied Corporation, Bendix Kansas City Division, Missouri (United States), BDX-613-3685, 18pp. (Feb. 1987) Investigation was continued on three ultrasonic methods and one combination of methods for the nondestructive measurement of residual stress in metal parts. Experiments were designed and transducers were modified such that all measurements could be made using only single surface contact to a flat area no larger than 25 m m square. Transducer adaptability for use on curved surfaces was also considered to be important.
37339 Fukuoka, H. Ultrasonic measurement of residual stress Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United States), 18-20 Sep. 1985. pp. 275-300. Martinus Nijhoff Publishers ( ! !)87) The main point of this paper is a practical application of acoustoelastic measurement of residual stress in industry. 37338
Heyman, J.S.; Namkung, M.
Residual stress measurements in carbon steel
36505
Pritchard, S.E.
The use of ultrasonics for residual stress analysis NDT International, Vol. 20, No. I, pp. 57-60 (Feb 1987) A 'critical size' defect, as defined in fracture mechanics calculations, is influenced by the fracture toughness and microstructure of the material in the vicinity of the crack and also by the level of local stress assisting or impeding crack development. It has been realized at the National NDT Centre for some time that a balanced assessment of crack significance requires not only detailed information on crack location, crack dimensions and crack nature, but also quantitative data on microstructural variations and on levels of residual stress. The present paper discusses Harwelrs programme in recent years to develop an ultrasonic technique to assess residual stress.
Clark, A.V.; Moulder, J.C., Mignogna, R.B.; DelSanto,
P.P. A comparison of several ultrasonic techniques for absolute stress determination in the presence of texture Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United Stales), 18-20 Sep. 1985. pp. 345-360. Martinus Nijhoff Publishers (1987)
Each entry in NDT Abstracts consists of the serial number in the National NDT Centre Information Store for identification purposes; the title of the paper, book or report; the name of the author; the name of the source journal or document and the abstracts. Where necessary, author's names and the title of foreign j ournals have been transliterated into the Latin alphabet according to British Standard BS 2979:1958.
Information Service. US Department of Commerce, Springfield, Virginia 22151, USA. British and foreign standards can be obtained from Sales Department, British Standards Institution, 101 Pentonville Road, London NI 9ND; and British and foreign patents from the Patents Office Sales Branch, Block C, Station Square House, St Mary Cray, Orpington, Kent BR5 3RD.
Availability of Publications
Information-retrievalService
Most papers listed may be obtained as loans or copies via local library or direct from Loans Department, British Library Document Supply Centre, Boston Spa, Wetherby, Yorkshire LS23 7BQ. Details of the British Lending Library's UK and International Services may be obtained from The Director, BritzLshLibrary Lending Division. Technical reports are also available from the Loans Department of the British Lending Library and in the USA from the National Technical
All entries are indexed in a computerized retrieval system, located at Harwell, which allows rapid searching of information relevant to any particular inspection problem. This service is available to both UK and overseas organizations through the National NDT Centre's Qualtis Subscription Scheme - further details are available from Phil Lawrence on Abingdon (0235) 433391. :~ 1994 United Kingdom Atomic Energy Authority
121