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Steel grading by micromagnetic techniques
NDT Abstracts 53394 Mohamed, A.Z.; Wafik, A.H.; Yousef, M. M i c r o s t r u c t u r e a n d B a r k h a u s e n j u m p s in a n N i - C r eutectoid
52761 Sipahi, L.B.; Jiles, D. A n investigation of various procedures for analysis of micromagnetic B a r k h a n s e n signals for n o n d e s t r u c t i v e evaluation of steels Nondestructive Testing and Evaluation, Vol. 10, No. 3, pp. 183-199 0993) Current research undertaken at Iowa State University has been concerned with both the theoretical and experimental aspects of the Barkhausen effect. Here we discuss mainly the experimental techniques and including new Barkhausen effect instrumentation to detect and measure the emissions from ferromagnetic materials under the action of an alternating magnetic field. The capability of the system includes measurements of RMS Barkhausen voltage signals induced in a flux coil, pulse height analysis of these signals, frequency spectrum analysis, and Barkhausen pulse count rate analysis.
steel Journal of Physics D. Applied Physics, Vol. 26, No. 9, pp. 1448-1452 (1993) The decomposition of anstenite following the initial rapid formation of bainitic ferrite in a eutectoid steel containing nominally ! st% Ni and I wt% Cr isothermally transformed in the bainitic region of the time- temperature transform diagram has been studiod. The microstructure and kinetics were studied using both optical and electron microscopy. Also, the mean potential difference V and the frequency F of Barkhausen jumps were measured for various bainitic transform products. Lower bainite with fine carbides shows the higher values of F and V. The, formation of upper bainite with coarser carbides leads to a considerable decrease of F and V, while in the region of upper bainite and spiky pearlite F and V increase slightly. The relative amount of the eddy currents depends on the transformation products.
52757 Govindaraju, M.R.; Strom, A.; Jiles, D.C.; Biner, S.B.; Chen, Z.J.
53037 Kuznetsov, N.S. E x a m i n a t i o n of the relationship of parameters of m a g n e t i c noise with c h a n g e s in t h e s t r u c t u r e of f e r r o m a g n e t i c steels Technical Diagnostics and Nondestructive Testing, Vol. 4, No. 4, pp. 238-241 0 9 9 2 ) The author presents the results of investigations carried out to evaluate the relationships of the emf of magnetic noise and the strength of the coercive field with the most probable dimensions of the domain in ferromagnetic steels. The results show that the value of the emf of the magnetic noise increases with an increase of the size of the domain and the strength of the coercive field decreases. The results of application of the magnetic noise in practice for nondestructive inspection of the quality of steel components are presented.
E v a l u a t i o n of fatigue d a m a g e in steel s t r u c t u r a l c o m p o n e n t s by magnetoelastic B a r k h a u s e n signal analysis Journal of Applied Physics, Vol. 73, No. 10, pp. 6165-6167 (15 May 1993) This paper is concerned with using a magnetic technique for the evaluation of fatigue damage in steel structural components. It is shown that Barkhausen effect measurements can be used to indicate impending failure due to fatigue under certain conditions. The Barkhausen signal amplitude is known to be highly sensitive to changes in density and distribution of dislocations in materials. The sensitivity of Barkhausen signal amplitude I~ fatigue damage has been studied in the low-cycle fatigue regime using smooth tensile specimens of a medium strength steel. The Barkhausen measurements were taken at depths of penetration of 0.02, 0.07, and 0.2 ram. It was found that changes in magnetic properties are sensitive to microstructural changes taking place at the surface of the material throughout the fatigue life.
52767 Lamontanara, J; Chicois, J; Fleischmann, P; Fougeres, R M o n i t o r i n g fatigue d a m a g e in i n d u s t r i a l steel by b a r k h a u s e n noise Nondestructive Characterization of Materials V, Karuizawa (Japan), 27- 30 May 1991. pp 603-614. Edited by T. Kishi, T. Saito, C. Ruud and R. Green. Iketanii Science and Technology Foundation (1993) Barkhausen noise measurements were performed in order to detect the microstructure changes and the initiation of the damage in the case of a cyclic strained industrial steel. The influence of the number of cycles and the unloading mode, on the Barkhausen noise, is studied. Fatigue tests are performed according to a push-pull mode under total strain controlled conditions. Results are analyzed from the microstructural changes by cyclic deformation of the steel specially taking into account the sign and the level of internal stress field as well as changes in the density of crystal defects, the precipitation state, and the initiation and the development of microcracks. Finally characteristics of Barkhausen peaks are proposed as indicators of the fatigue damage.
Swartzendruber, L.I.; Hicho, G.E. Effect of sensor c o n f i g u r a t i o n o n m a g n e t i c Barkhausen 52756
observations Research in Nondestructive Evaluation, Vol. 5, No. 1, pp. 41-50 (1993) A number of characteristics of the magnetic Barkhausen signal, including power density, autocorrelation, jumpsum density, and noise emission rates, are obtained with different sensor types on low-carbon sheet steels and compared. The steel samples used in this study produced single, narrow Barkhausen peaks and the shapes of the rms voltage and jumpsum curves were found to be nearly independent of the sensor type. 52754 Dhar, A.; Atherton, D.L. C o r r e l a t i o n between m a g n e t i c flux leakage a n d m a g n e t i c B a r k h a u s e n noise in steel pipelines British Journal of Nondestructive Testing, Vol. 35, No. 6, pp. 307-309 (Jun. 1993) Magnetic Barkhausen Noise (MBN) measurements were made around the circumference of a 610 mm pipeline section. A strong variation in the measured MBN activity was found. This variation is attributed to the residual stress concentrations resulting from the metallurgical processing. Magnetic Flux Leakage (MFL) measurements were made over five identical defects deliberately introduced in the pipeline section at different regions of Barkhausen Noise activity. The defect-induced MFL signals showed an almost linear correlation with the MBN rms voltage in the region of the defect.
52766 Kohle, T.D; Sengupta, A.K; Dobmann, G; Kroning, M Steel g r a d i n g by m i c r o m a g n e t i c techniques Nondestructive Characterization of Materials V, Karuizawa (Japan), 27- 30 May 1991. pp 615-621. Edited by T. Kishi, T. Saito, C. Ruud and R. Green. Iketani Science and Technology Foundation (1993) Tube samples of six different steel qualities namely ST 35, ST 45, ST 52, ST 55, ST 65 (DIN standards 2391 T2) and 10 CrMo 9 10 (DIN standard 17175) and four different kinds of thermomechanical treatments (eg cold worked; cold worked and annealed; cold worked, annealed and cold drawn; the one without proper cold working for ST 65 and 10 CrMo 9 I 0 only) were sorted by the micromagnetic methods on the basis of the different magnetic properties of these materials. Magnetic Barkhausen noise (MBN) the cnercivity (H) corresponding to maximum MBN, distortion factor (k) and the coercivity (H) derived from the upper harmonics of the tangential field strength were measured and estimated for each tube sample using a laboratory set-up.
52559 Kwon, O-Y.; Ono, K. Detection of irradiation effects on reactor vessel steels by magneto- acoustic emission 9th InternationalConference on Nondestructive Evaluation in the Nuclear Industry, Tokyo (Japan), 25-28 Apr. 1988, pp. 575-582. Edited by K. lida,J.E. Doherty and X. Edelmann. A S M (1988)
52762 Jayakumar, T.; Koh~!e,T.D.; Theiner, W.A.; Raj, B. M a g n e t i c methods for c h a r a c t e r i s a t i o n of cold rolled AISI type 304 stainless steel Nondestructive Testing and Evaluation, Vol. 10, No. 4, pp. 205-214 (1993) Magnetic hysteresis loop and magnetic and acoustic Barkhausen noise measurements have been made to characterise strain induced ~'- martensite in cold worked AISI type 304 stainless steel. Both magnetic hysteresis and MBN measurements are found to be more sensitive in detection of ct'-martensite as compared to equivalent o'- ferrite and X-ray diffraction measurements. ABN signals could be observed only in the case of 50% cold worked specimens containing high amount of c(-martensite.
The irradiation effects of reactor vessel steels were studied by magneto-acoustic emission (MAE). Two commercial steels, A302B plate and A533B weld, and two model alloys were irradiated at four different conditions: high and low flux, two fiuence levels (0.5 or 1 x 10(sup(19) n/cm sup (2)) and three temperatures (271,288 and 307sup(o)C). For each material/condition and unirradiated control samples, MAE intensity in rms voltage with increasing magnetic field was measured. MAE waveform analysis can monitor the microscopic changes in the steel components subjected to neutron irradiation.
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52761 Sipahi, L.B.; Jiles, D. A n investigation of various procedures for analysis of micromagnetic B a r k h a n s e n signals for n o n d e s t r u c t i v e evaluation of steels Nondestructive Testing and Evaluation, Vol. 10, No. 3, pp. 183-199 0993) Current research undertaken at Iowa State University has been concerned with both the theoretical and experimental aspects of the Barkhausen effect. Here we discuss mainly the experimental techniques and including new Barkhausen effect instrumentation to detect and measure the emissions from ferromagnetic materials under the action of an alternating magnetic field. The capability of the system includes measurements of RMS Barkhausen voltage signals induced in a flux coil, pulse height analysis of these signals, frequency spectrum analysis, and Barkhausen pulse count rate analysis.
steel Journal of Physics D. Applied Physics, Vol. 26, No. 9, pp. 1448-1452 (1993) The decomposition of anstenite following the initial rapid formation of bainitic ferrite in a eutectoid steel containing nominally ! st% Ni and I wt% Cr isothermally transformed in the bainitic region of the time- temperature transform diagram has been studiod. The microstructure and kinetics were studied using both optical and electron microscopy. Also, the mean potential difference V and the frequency F of Barkhausen jumps were measured for various bainitic transform products. Lower bainite with fine carbides shows the higher values of F and V. The, formation of upper bainite with coarser carbides leads to a considerable decrease of F and V, while in the region of upper bainite and spiky pearlite F and V increase slightly. The relative amount of the eddy currents depends on the transformation products.
52757 Govindaraju, M.R.; Strom, A.; Jiles, D.C.; Biner, S.B.; Chen, Z.J.
53037 Kuznetsov, N.S. E x a m i n a t i o n of the relationship of parameters of m a g n e t i c noise with c h a n g e s in t h e s t r u c t u r e of f e r r o m a g n e t i c steels Technical Diagnostics and Nondestructive Testing, Vol. 4, No. 4, pp. 238-241 0 9 9 2 ) The author presents the results of investigations carried out to evaluate the relationships of the emf of magnetic noise and the strength of the coercive field with the most probable dimensions of the domain in ferromagnetic steels. The results show that the value of the emf of the magnetic noise increases with an increase of the size of the domain and the strength of the coercive field decreases. The results of application of the magnetic noise in practice for nondestructive inspection of the quality of steel components are presented.
E v a l u a t i o n of fatigue d a m a g e in steel s t r u c t u r a l c o m p o n e n t s by magnetoelastic B a r k h a u s e n signal analysis Journal of Applied Physics, Vol. 73, No. 10, pp. 6165-6167 (15 May 1993) This paper is concerned with using a magnetic technique for the evaluation of fatigue damage in steel structural components. It is shown that Barkhausen effect measurements can be used to indicate impending failure due to fatigue under certain conditions. The Barkhausen signal amplitude is known to be highly sensitive to changes in density and distribution of dislocations in materials. The sensitivity of Barkhausen signal amplitude I~ fatigue damage has been studied in the low-cycle fatigue regime using smooth tensile specimens of a medium strength steel. The Barkhausen measurements were taken at depths of penetration of 0.02, 0.07, and 0.2 ram. It was found that changes in magnetic properties are sensitive to microstructural changes taking place at the surface of the material throughout the fatigue life.
52767 Lamontanara, J; Chicois, J; Fleischmann, P; Fougeres, R M o n i t o r i n g fatigue d a m a g e in i n d u s t r i a l steel by b a r k h a u s e n noise Nondestructive Characterization of Materials V, Karuizawa (Japan), 27- 30 May 1991. pp 603-614. Edited by T. Kishi, T. Saito, C. Ruud and R. Green. Iketanii Science and Technology Foundation (1993) Barkhausen noise measurements were performed in order to detect the microstructure changes and the initiation of the damage in the case of a cyclic strained industrial steel. The influence of the number of cycles and the unloading mode, on the Barkhausen noise, is studied. Fatigue tests are performed according to a push-pull mode under total strain controlled conditions. Results are analyzed from the microstructural changes by cyclic deformation of the steel specially taking into account the sign and the level of internal stress field as well as changes in the density of crystal defects, the precipitation state, and the initiation and the development of microcracks. Finally characteristics of Barkhausen peaks are proposed as indicators of the fatigue damage.
Swartzendruber, L.I.; Hicho, G.E. Effect of sensor c o n f i g u r a t i o n o n m a g n e t i c Barkhausen 52756
observations Research in Nondestructive Evaluation, Vol. 5, No. 1, pp. 41-50 (1993) A number of characteristics of the magnetic Barkhausen signal, including power density, autocorrelation, jumpsum density, and noise emission rates, are obtained with different sensor types on low-carbon sheet steels and compared. The steel samples used in this study produced single, narrow Barkhausen peaks and the shapes of the rms voltage and jumpsum curves were found to be nearly independent of the sensor type. 52754 Dhar, A.; Atherton, D.L. C o r r e l a t i o n between m a g n e t i c flux leakage a n d m a g n e t i c B a r k h a u s e n noise in steel pipelines British Journal of Nondestructive Testing, Vol. 35, No. 6, pp. 307-309 (Jun. 1993) Magnetic Barkhausen Noise (MBN) measurements were made around the circumference of a 610 mm pipeline section. A strong variation in the measured MBN activity was found. This variation is attributed to the residual stress concentrations resulting from the metallurgical processing. Magnetic Flux Leakage (MFL) measurements were made over five identical defects deliberately introduced in the pipeline section at different regions of Barkhausen Noise activity. The defect-induced MFL signals showed an almost linear correlation with the MBN rms voltage in the region of the defect.
52766 Kohle, T.D; Sengupta, A.K; Dobmann, G; Kroning, M Steel g r a d i n g by m i c r o m a g n e t i c techniques Nondestructive Characterization of Materials V, Karuizawa (Japan), 27- 30 May 1991. pp 615-621. Edited by T. Kishi, T. Saito, C. Ruud and R. Green. Iketani Science and Technology Foundation (1993) Tube samples of six different steel qualities namely ST 35, ST 45, ST 52, ST 55, ST 65 (DIN standards 2391 T2) and 10 CrMo 9 10 (DIN standard 17175) and four different kinds of thermomechanical treatments (eg cold worked; cold worked and annealed; cold worked, annealed and cold drawn; the one without proper cold working for ST 65 and 10 CrMo 9 I 0 only) were sorted by the micromagnetic methods on the basis of the different magnetic properties of these materials. Magnetic Barkhausen noise (MBN) the cnercivity (H) corresponding to maximum MBN, distortion factor (k) and the coercivity (H) derived from the upper harmonics of the tangential field strength were measured and estimated for each tube sample using a laboratory set-up.
52559 Kwon, O-Y.; Ono, K. Detection of irradiation effects on reactor vessel steels by magneto- acoustic emission 9th InternationalConference on Nondestructive Evaluation in the Nuclear Industry, Tokyo (Japan), 25-28 Apr. 1988, pp. 575-582. Edited by K. lida,J.E. Doherty and X. Edelmann. A S M (1988)
52762 Jayakumar, T.; Koh~!e,T.D.; Theiner, W.A.; Raj, B. M a g n e t i c methods for c h a r a c t e r i s a t i o n of cold rolled AISI type 304 stainless steel Nondestructive Testing and Evaluation, Vol. 10, No. 4, pp. 205-214 (1993) Magnetic hysteresis loop and magnetic and acoustic Barkhausen noise measurements have been made to characterise strain induced ~'- martensite in cold worked AISI type 304 stainless steel. Both magnetic hysteresis and MBN measurements are found to be more sensitive in detection of ct'-martensite as compared to equivalent o'- ferrite and X-ray diffraction measurements. ABN signals could be observed only in the case of 50% cold worked specimens containing high amount of c(-martensite.
The irradiation effects of reactor vessel steels were studied by magneto-acoustic emission (MAE). Two commercial steels, A302B plate and A533B weld, and two model alloys were irradiated at four different conditions: high and low flux, two fiuence levels (0.5 or 1 x 10(sup(19) n/cm sup (2)) and three temperatures (271,288 and 307sup(o)C). For each material/condition and unirradiated control samples, MAE intensity in rms voltage with increasing magnetic field was measured. MAE waveform analysis can monitor the microscopic changes in the steel components subjected to neutron irradiation.
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