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Effects of grain size and cooling rate on magnetoacoustic stress measurement in AISI 4140 steel
40580 Gremaud, G. Study of the dislocation dynamics by ultrasonic cyclic bias stress experiments U l t r a s o n i c M e t h o d s In E v a l u a t i o n of I n h o m o g e n e o u s M a t e r i a l s , P r o c e e d i n g s , E r i c e , ( I t a l y ) , 15-25 Oct. 1985, pp. 187-196. E d i t e d by A . A l i p p i a n d W . G . M a y e r , N a t o A d v a n c e d S t u d y I n s t i t u t e Series E A p p l i e d Sciences, Vol. 126, M a r t i n u s Nijhoff, 1987 In this new technique attenuation, alpha, and velocity, v, of ultrasonic waves are measured in a sample subjected to a low frequency cyclic stress, sigma. Closed curves DELTA alpha (sigma) and DELTA v/v(sigma) are measured during each cycle of the applied stress. The shapes of these curves and their evolution characterize each mechanism controlling the dislocation motion. The shapes of these curves have been called the signatures of the mechanisms controlling the dislocation dynamics. In this paper, it will be shown that the closed curves DELTA alpha (sigma) and DELTAv/v (sigma) can be called the signatures of a particular dislocation motion mechanism and how powerful this technique is in finding the mechanisms controlling the dislocation dynamics. 40506
Wedgwood, F.A.
Some optical methods of characterizing solid and particulate materials during manufacturing processes N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 643-656. E d i t e d by J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 In this paper two methods of non-invasive measurement using lasers will be described, which can be made on hot or fast moving materials and hence at an early stage in some manufacturing processes. The first method is generation and detection of ultrasound in solids. This can be used for measuring grain scattering and attenuation of ultrasound using lasers of moderate power. Applications include measurement of grain size in metals during rolling operations and monitoring during welding. The second method is optical sizing of particles or droplets in a gas stream. Instrumentation has been refined so that a wide range of particle sizes and types can be measured. Applications to powder metallurgy, plasma spraying, spray drying and paint spraying will be described. In application to paint spray quality control it was found that the economical solution in practice is to develop an accurate model using the optical measurements for validation and use the model, with cheaper on-line measurements, for process control. 40440
Canella, G.; Taddei, M.
Correlation between ultrasonic attenuation and fracture toughness of steels N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 261-270. E d i t e d by J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 An ultrasonic index has been found for direct NDT estimation of the fracture toughness of three different steels; one forged bainitic and two rolled: ferritic-pearlitic and acicular ferritic. Direct correlations have been found between ultrasonic attenuation and Critical Stress Intensity Factor in plain strain (K/sub IC/), Ductile Fracture Appearance Transition Temperature of Charpy-V curve (FATT) and Shelf Energy of the Charpy-V curve itself (KV). A direct correlation has also been found between fracture toughness indices and grain size. To obtain these results a new method has been developed for measuring ultrasonic attenuation at room temperature on thin specimens even at high absorption. 40434
Birring,A.S.; Hanley, J.J.
Effect of cavities on ultrasonic attenuation and velocity N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 673-682. E d i t e d b y J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 A theoretical investigation of nondestructive ultrasonic methods for detection of creep cavitation in steels was performed. Ultrasonic scattering theories were converted into computer software and used to predict the effect of cavities on ultrasonic attenuation and velocity. From the results, it was theoretically concluded that measurements of absolute velocity and velocity and attenuation variation with frequency have a strong potential to detect cavitation. The study also looked at the effects of scattering from grain boundaries and from graphite and carbide inclusions in steels. Grain scattering affects attenuation and velocity, and methods were formulated to compensate for such effects. The scattering from inclusions is expected to be less than that from cavities, as cavities produce a higher impedance mismatch than inclusions. The study concludes that ultrasonic methods will be able to detect creep cavitation in carbon steels used for high-temperature applications. 40420
Delsanto, P.P.; Mignogna, R.B.; Clark, A. V. Jr.
Ultrasonic texture analysis for polycrystalline aggregates of cubic materials displaying orthotropic symmetry N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul. 1986. pp. 535-544. E d i t e d b y J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 The propagation of Rayleigh Waves (RW) on the surface of unstressed materials is studied in this paper in an attempt to distinguish between the effects of stress and texture. Material anisotropy is then defined by the elastic constants of the crystallites and their orientation distribution function (which is a way of measuring texture). Changes in RW phase velocity are measured due to slight anisotropy and a formula derived. This general formula is then applied to the special case of an orthotropic distribution of cubic crystallites (such as rolled plates of aluminium, copper and iron). The change in RW velocity is given by
NDT International October 1989
the CODF and the elastic constants of the crystallites. Finally the texture of the sample is determined.
Mignogna, R.B.; Delsanto, P . P . ; Clark, A.V. Jr.; Rath, B.B.; Void, C.L. 40419
U l t r a s o n i c measurements on t e x t u r e d m a t e r i a l s N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul. 1986. pp. 545-554. E d i t e d b y J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 Ultrasonic measurements of texture are described together with theoretical results for Rayleigh waves incorporating crystallite orientation distribution functions. Acoustic birefringence results support the surface wave results and show texture variations through the plate thickness. Results of surface waves to bulk or plate waves in the presence of texture and stress inhomogeneity is also discussed. 40415
Electric Power Research Institute
Lamb Wave inspection for large cracks in centrifugally cast stainless steel E l e c t r i c P o w e r R e s e a r c h I n s t i t u t e , Palo A l t o , C a l i f o r n i a ( U n i t e d States), E P R I N P 5963, 120 pp. ( A u g . 1988) The detection of sizing of cracks in centrifugally cast stainless steel (CCSS) is not rehable with standard ultrasonic techniques which are based on bulk wave propagation. However, Lamb waves which propagate in a subsurface mode, can detect cracks that penetrate into the outer 20% of a component wall. This has important safety implications for PWR piping. Liquid-wedge transducers were used and after the study, the most effective frequencies and transducer separation distances could be assessed. Further investigation is needed to back up this initial study. 40387
Utrata, D.; Namkung, M.
Effects of Grain size and cooling rate on magnetoacousfic stress measurement in AISI 4140 steel N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 605-614. E d i t e d b y J.E. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 Effects of microstructures on the uniaxial stress dependence of low- field magnetoacoustic response were studied. Test samples were cut from a steel bar and heat treated to obtain both coarse- and fine- grained specimens for study. The specific test procedure involved measurement of the fractional frequency shift of phase-locked ultrasonic waves propagated in a sample simultaneously being magnetized. Curves of frequency shift vs. magnetic induction were then obtained for each specimen at various applied test loads. The results indicate that both the permeability of the samples and the quantitative behavior of the fractional frequency shift curves are dependent on heat treatment and microstructure. Qualitatively, the test results from this study agree with previous investigations of various low- and medium-carbon steels. It is concluded that the stress dependence of acoustic fractional frequency shift exhibited in the magnetoacoustic test method is more dependent on carbon content than on microstructure. 40310
Baaklini, G.Y.; Generazio, E.R.; Kiser, J.D.
High frequency ultrasonic characterization of sintered SiC N a t i o n a l A e r o n a u t i c s a n d Space A d m i n i s t r a t i o n , C l e v e l a n d , O H . L e w i s R e s e a r c h C e n t e r ( U n i t e d States), N88-23985, 19 pp. (1987) High frequency (60 to 160 MHz) ultrasonic nondestructive evaluation was used to characterize variations in density and microstructural constituents of sintered SiC bars. Ultrasonic characterization methods included longitudinal velocity, reflection coefficient, and precise attenuation measurements. The SiC bars were tailored to provide bulk densities ranging from 90 to 98 percent of theoretical, average grain sizes ranging from 3.0 to 12.0 microns, and average pore sizes ranging from 1.5 to 4.0 microns. Velocity correlated with specimen bulk density irrespective of specimen average grain size, average pore size, and average pore orientation. Attenuation coefficient was found to be sensitive to both density and average pore size variations, but was not affected by large differences in average grain size. 40281 Saniie, J.; Wang, T.; Bilgutay, N.M. S p e c t r a l evaluation of u l t r a s o n i c g r a i n s i g n a l s P r o c e e d i n g s of the I E E E 1987 U l t r a s o n i c S y m p o s i u m , D e n v e r , C o l o r a d o ( U n i t e d States), 14-16 Oct. 1987. Vol. 2, pp. 1015-1026. E d i t e d by B . R . M c A v o y . I n s t i t u t e of E l e c t r i c a l a n d E l e c t r o n i c s Engineers. The ultrasonic wave traveling through solids is subject to energy losses due to scattering and absorption. In the Rayleigh scattering region, both scattering and absorption are functions of frequency and grain size distribution. Grain scattering results in an upward shift in the expected frequency of a broadband ultrasonic wave, while the attenuation effect influences the frequency shift in a downward direction. These opposing phenomena can be utilized for grain size evaluation. In this report, a spectral-shift quantization technique is presented using homomorphic processing and moment analysis. Computer simulation and experimental results obtained from steel samples with different grain sizes support the feasibility of using spectral quantization techniques for grain size characterization. 40139 Reno, R.C.; Fields, R.J.; Clark, A.V. Jr. C r y s t a l l o g r a p h i c t e x t u r e in rolled a l u m i n u m plates: neutron pole f i g u r e
measurements
303
Wedgwood, F.A.
Some optical methods of characterizing solid and particulate materials during manufacturing processes N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 643-656. E d i t e d by J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 In this paper two methods of non-invasive measurement using lasers will be described, which can be made on hot or fast moving materials and hence at an early stage in some manufacturing processes. The first method is generation and detection of ultrasound in solids. This can be used for measuring grain scattering and attenuation of ultrasound using lasers of moderate power. Applications include measurement of grain size in metals during rolling operations and monitoring during welding. The second method is optical sizing of particles or droplets in a gas stream. Instrumentation has been refined so that a wide range of particle sizes and types can be measured. Applications to powder metallurgy, plasma spraying, spray drying and paint spraying will be described. In application to paint spray quality control it was found that the economical solution in practice is to develop an accurate model using the optical measurements for validation and use the model, with cheaper on-line measurements, for process control. 40440
Canella, G.; Taddei, M.
Correlation between ultrasonic attenuation and fracture toughness of steels N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 261-270. E d i t e d by J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 An ultrasonic index has been found for direct NDT estimation of the fracture toughness of three different steels; one forged bainitic and two rolled: ferritic-pearlitic and acicular ferritic. Direct correlations have been found between ultrasonic attenuation and Critical Stress Intensity Factor in plain strain (K/sub IC/), Ductile Fracture Appearance Transition Temperature of Charpy-V curve (FATT) and Shelf Energy of the Charpy-V curve itself (KV). A direct correlation has also been found between fracture toughness indices and grain size. To obtain these results a new method has been developed for measuring ultrasonic attenuation at room temperature on thin specimens even at high absorption. 40434
Birring,A.S.; Hanley, J.J.
Effect of cavities on ultrasonic attenuation and velocity N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 673-682. E d i t e d b y J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 A theoretical investigation of nondestructive ultrasonic methods for detection of creep cavitation in steels was performed. Ultrasonic scattering theories were converted into computer software and used to predict the effect of cavities on ultrasonic attenuation and velocity. From the results, it was theoretically concluded that measurements of absolute velocity and velocity and attenuation variation with frequency have a strong potential to detect cavitation. The study also looked at the effects of scattering from grain boundaries and from graphite and carbide inclusions in steels. Grain scattering affects attenuation and velocity, and methods were formulated to compensate for such effects. The scattering from inclusions is expected to be less than that from cavities, as cavities produce a higher impedance mismatch than inclusions. The study concludes that ultrasonic methods will be able to detect creep cavitation in carbon steels used for high-temperature applications. 40420
Delsanto, P.P.; Mignogna, R.B.; Clark, A. V. Jr.
Ultrasonic texture analysis for polycrystalline aggregates of cubic materials displaying orthotropic symmetry N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul. 1986. pp. 535-544. E d i t e d b y J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 The propagation of Rayleigh Waves (RW) on the surface of unstressed materials is studied in this paper in an attempt to distinguish between the effects of stress and texture. Material anisotropy is then defined by the elastic constants of the crystallites and their orientation distribution function (which is a way of measuring texture). Changes in RW phase velocity are measured due to slight anisotropy and a formula derived. This general formula is then applied to the special case of an orthotropic distribution of cubic crystallites (such as rolled plates of aluminium, copper and iron). The change in RW velocity is given by
NDT International October 1989
the CODF and the elastic constants of the crystallites. Finally the texture of the sample is determined.
Mignogna, R.B.; Delsanto, P . P . ; Clark, A.V. Jr.; Rath, B.B.; Void, C.L. 40419
U l t r a s o n i c measurements on t e x t u r e d m a t e r i a l s N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul. 1986. pp. 545-554. E d i t e d b y J.F. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 Ultrasonic measurements of texture are described together with theoretical results for Rayleigh waves incorporating crystallite orientation distribution functions. Acoustic birefringence results support the surface wave results and show texture variations through the plate thickness. Results of surface waves to bulk or plate waves in the presence of texture and stress inhomogeneity is also discussed. 40415
Electric Power Research Institute
Lamb Wave inspection for large cracks in centrifugally cast stainless steel E l e c t r i c P o w e r R e s e a r c h I n s t i t u t e , Palo A l t o , C a l i f o r n i a ( U n i t e d States), E P R I N P 5963, 120 pp. ( A u g . 1988) The detection of sizing of cracks in centrifugally cast stainless steel (CCSS) is not rehable with standard ultrasonic techniques which are based on bulk wave propagation. However, Lamb waves which propagate in a subsurface mode, can detect cracks that penetrate into the outer 20% of a component wall. This has important safety implications for PWR piping. Liquid-wedge transducers were used and after the study, the most effective frequencies and transducer separation distances could be assessed. Further investigation is needed to back up this initial study. 40387
Utrata, D.; Namkung, M.
Effects of Grain size and cooling rate on magnetoacousfic stress measurement in AISI 4140 steel N o n d e s t r u c t i v e C h a r a c t e r i s a t i o n of M a t e r i a l s 2, M o n t r e a l ( C a n a d a ) , 21- 23 Jul, 1986. pp. 605-614. E d i t e d b y J.E. B u s s i e r e , J.P. M o n c h a l i n , C . O . R u u d , R . E . G r e e n Jr. P l e n u m Press, 1987 Effects of microstructures on the uniaxial stress dependence of low- field magnetoacoustic response were studied. Test samples were cut from a steel bar and heat treated to obtain both coarse- and fine- grained specimens for study. The specific test procedure involved measurement of the fractional frequency shift of phase-locked ultrasonic waves propagated in a sample simultaneously being magnetized. Curves of frequency shift vs. magnetic induction were then obtained for each specimen at various applied test loads. The results indicate that both the permeability of the samples and the quantitative behavior of the fractional frequency shift curves are dependent on heat treatment and microstructure. Qualitatively, the test results from this study agree with previous investigations of various low- and medium-carbon steels. It is concluded that the stress dependence of acoustic fractional frequency shift exhibited in the magnetoacoustic test method is more dependent on carbon content than on microstructure. 40310
Baaklini, G.Y.; Generazio, E.R.; Kiser, J.D.
High frequency ultrasonic characterization of sintered SiC N a t i o n a l A e r o n a u t i c s a n d Space A d m i n i s t r a t i o n , C l e v e l a n d , O H . L e w i s R e s e a r c h C e n t e r ( U n i t e d States), N88-23985, 19 pp. (1987) High frequency (60 to 160 MHz) ultrasonic nondestructive evaluation was used to characterize variations in density and microstructural constituents of sintered SiC bars. Ultrasonic characterization methods included longitudinal velocity, reflection coefficient, and precise attenuation measurements. The SiC bars were tailored to provide bulk densities ranging from 90 to 98 percent of theoretical, average grain sizes ranging from 3.0 to 12.0 microns, and average pore sizes ranging from 1.5 to 4.0 microns. Velocity correlated with specimen bulk density irrespective of specimen average grain size, average pore size, and average pore orientation. Attenuation coefficient was found to be sensitive to both density and average pore size variations, but was not affected by large differences in average grain size. 40281 Saniie, J.; Wang, T.; Bilgutay, N.M. S p e c t r a l evaluation of u l t r a s o n i c g r a i n s i g n a l s P r o c e e d i n g s of the I E E E 1987 U l t r a s o n i c S y m p o s i u m , D e n v e r , C o l o r a d o ( U n i t e d States), 14-16 Oct. 1987. Vol. 2, pp. 1015-1026. E d i t e d by B . R . M c A v o y . I n s t i t u t e of E l e c t r i c a l a n d E l e c t r o n i c s Engineers. The ultrasonic wave traveling through solids is subject to energy losses due to scattering and absorption. In the Rayleigh scattering region, both scattering and absorption are functions of frequency and grain size distribution. Grain scattering results in an upward shift in the expected frequency of a broadband ultrasonic wave, while the attenuation effect influences the frequency shift in a downward direction. These opposing phenomena can be utilized for grain size evaluation. In this report, a spectral-shift quantization technique is presented using homomorphic processing and moment analysis. Computer simulation and experimental results obtained from steel samples with different grain sizes support the feasibility of using spectral quantization techniques for grain size characterization. 40139 Reno, R.C.; Fields, R.J.; Clark, A.V. Jr. C r y s t a l l o g r a p h i c t e x t u r e in rolled a l u m i n u m plates: neutron pole f i g u r e
measurements
303