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Detection of fabrication stresses by the Barkhausen noise method
N DT Abstracts 38958
Kameda, J.
38030 Cook, K.V.; McClung, R.W. Flaw density examinations of a clad boiling water reactor
C h a r a c t e r i z a t i o n of t e m p e r e d m a r t e n s i t e m i c r o s t r u c t u r e and embrittlement by acoustic a n d m a g n e t i c B a r k h a u s e n signal
p r e s s u r e vessel segment Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States), NUREG-CR-4860, 30 pp. (Apr. 1987) As part of the Oak Ridge National Laboratory's Heavy-Section Steel Technology Program, studies have been conducted to determine flaw density in a section of reactor pressure vessel cut from the Hope Creek Unit 2 vessel. This boiling water reactor vessel was never in service. One objective was to evaluate the approximate 0.7 by 3-m (2- by 10-ft) segment of the vessel provided using ultrasonic flaw detection methods performed with both ASME Code techniques and supplemental ultrasonic methods. A second objective was to evaluate the inner surface stainless steel cladding for cracks with a high sensitivity penetrant examination. Both objectives were successfully completed.
measurement Scripta Metallurgica, Vol. 22, No. 9, pp. 1487-1492 (Sep. 1988) It has been well recognized that ultrahigh strength alloy steels exhibit embrittlement when they are tempered in the temperature range from 300 to 400sup(o)C. This phenomenon is referred to as tempered martensite embrittlement and is attributed to the occurrence of intergranular and/or cleavage fracture. The fracture mode depends on the alloy composition and the impurity content of steels. The intergranular embrittlement is caused by two events: segregation of impurities such as sulfur and phosphorus, and carbide precipitation at grain boundaries. The intergranular segregation of impurities during austenitization weakens grain boundaries and the precipitation of carbides during tempering promotes the nucleation and propagation of cracks. The objective of this study is to evaluate nondestrnctively the characteristics of tempered martensite microstructure and embrittlement in an ultrahigh strength steel by measuring the two types of Barkhausen signals.
37933
J.P. The
Scruby, C.B.; Buttle, D,I.; Briggs, G.A.D.; Jakubovics, monitoring
of
stress
and
microstructure
by
magnetoacoustic emission United Kingdom Atomic Energy Authority, Harwell, AERE-R12782, 16 pp. (Oct. 1987) Magnetoacoustic emission (MAE) is generated by Iocalised magnetostrictive strains when domain walls move in ferromagnetic materials. MAE amplitude is a function of internal and applied stresses: however it is also dependent upon the microstructure so that these two effects must be separated for practical applications. Using the ratio of MAE at high and low fields, there is good sensitivity to stress in certain mild steel microstructures (e.g. ferritic/pearlitic) and much lower sensitivity to heat treatment. In rapidly cooled microstructures however, there is a much greater sensitivity to microstructure. In a separate study MAE has been used to monitor the subtle microstructural changes that accompany neutron irradiation of steels. It is concluded that MAE should he developed further as a nondestructive method for measuring stress and monitoring microstructure.
Karjalainen, L.P.; Rautioaho, R.H. Detection of fabrication sltresses by the Barkhansen noise method 38843
The Effects of Fabrication Related Stresses on Product Manufacture and Performance, Cambridge (United Kingdom), 23-25 Sep. 1985. pp. 149-161. Edited by J.F. Alder. The Welding Institute (1987) The high efficiency of the magnetic Barkhausen noise method for qualitative detection of stress changes due to welding, thermal and mechanical stress relief, machining and shot peening in structural steels is demonstrated. The importance of properly adjusting the strength of magnetization is pointed out. The steel composition, metallurgical structure, texture, dislocations and biaxiality of the stress field all affect the inherent Barkhansen noise level and its .,=tressdependence, so that calibration for accurate determination of stress magnitudes does not generally seem reasonable. Examples of the practical applications of the method are briefly outlined.
37930
38249 Ranjan, R. M i c r o s t r u c t u r a l characterization of ferromagnetic materials
Ranjan,R.
M i c r o s t r u c t n r a l c h a r a c t e r i z a t i o n of ferromagnetic m a t e r i a l s using magnetic NDE techniques Dissertation Abstracts International, Voi. 48, No. 4, p. 1129 (Oct. 1987) Magnetic NDE techniques, namely, the acoustic Barkhausen noise, the magnetic Barkhausen noise and the magnetic hysteresis curves, were simultaneously used for microstructural characterization of nickel and steels. Results showed that, in nickel, the non-180 deg domain wails interact more strongly with dislocations than the 180 deg domain walls. A study of the grain size effect on the magnetic and acoustic Barkhausen noises showed a great potential as a NDE grain size measurement tool. Moreover, the Barkhausen signals indicate that the 180 deg domain walls in nickel seem to have a stronger interaction with grain boundaries than the non-180 deg domain walls, as indicated by the acoustic Barkhausen signal. Based on the experimental observations, a theoretical model is being proposed to explain the grain size effect on the Barkhausen signals.
using magnetic NDE techniques Ames Laboratory, Ames, Iowa (United States), IS-T-1231, DE87010918, 117 pp. (Jun. 1987) Magnetic NDE techniques, namely, the acoustic Barkhausen noise, the magnetic Barkhausen noise and the magnetic hysteresis curves, were simultaneously used for microstrnctural characterization of nickel and steels. Results showed that, in nickel, the non-180 deg domain walls interact more strongly with dislocations t!han the 180 deg domain walls. A study of the grain size effect on the magnetic and acoustic Barkhausen noises showed a great potential as a NDE grain size measurement tool. Moreover, the Barkhausen signals indicate that the 180 deg domain walls in nickel seem to have a stronger interaction with grain boundaries than the non-180 deg domain walls, as indicated by the acoustic Barkhausen signal. Based on the experimental observations, a theoretical model is being proposed to explain the grain size effect on the Barkhansen signals. The model takes into account the density of magnetic domain walls and their initial velocity, with both quantities being strongly dependent on microstructure. The acoustic and magnetic Barkhausen noises were also found to he very sensitive to the change in carbide morphology.
Hetherington, M.G.; Jakubovics, J.P.; Szpunar, J.A.; Tanner, B.K. 37631
High-voltage L o r e n t z electron microscopy studies of d o m a i n s t r u c t u r e s a n d m a g n e t i z a t i o n processes in pearlitic steels Philosophical Magazine B, Voi. 56, No. 5, pp. 561-577 (Nov. 1987) Pearlitic steels with volume fractions of pearlite from 5 to 100% have been studied using a high-voltage electron microscope and by measuring the Barkhausen activity. The results indicate that the microstructural parameters that affect the coercivity most strongly are the volume fractions and grain sizes of ferrite and pearlite. In electron microscope studies it was observed that domain walls were particularly strongly pinned in cementite lamellae in pearlite grains. A simple model is derived from these observations, which correctly predicts the coercivity of a large number of steels.
38238 Buttle, D.I.; Scruby, C.B.; Briggs, G.A.D.; Jakubovics, J.P. The measurement of stress in steels of v a r y i n g m i c r o s t r u c t u r e by magnetoacoustic and B a r k h a u s e n emission Proceedings of the Royal Society of London Series A, Vol. 414, No. 1847, pp. 469-497 (1987) Magnetoacoustic emission (MAE) and Barkhausen emission (BE) have been measured as a function of applied magnetic field and tensile stress from mild-steel samples in a wide range of heat treatments, to develop a technique to measure stress without prior knowledge of the microstructure. The results are supplemented by measurements of magnetic coercivity and mechanical hardness. MAE is found to decrease with increasing applied stress, whereas the variation of BE is more complicated. The amplitudes of both MAE and BE, as well as the coercivity and hardness are also found to depend on the microstructure to varying degrees. The dependence of MAE and BE on magnetic field are discussed in terms of domain-wall nucleation and irreversible motion in ferri~te at higher fields, and irreversible wall motion through martensite or pearlite at lower fields. The results imply that MAE can be used alone to measure stress provided the general form of the microstructure is known; otherwise BE can he used as an additional technique to resolve any ambiguity.
37495 Rautioaho,R.; Karjalainen, P.; Moilanen, M. Stress response of B a r k h a u s e n noise in a t e m p e r e d C - M n steel Journal of Magnetism and Magnetic Materials, Vol. 68, No. 3, pp. 314- 320 (Sep. 1987) The dependence of Barkhausen noise on tensile stress is measured in a high strength vanadium microailoyed C-Mn steel after tempering at 200, 400, 500, 600 and 650 C. Simultaneously, the coercive force and two field parameters related to the magnetic reversal curve are recorded for some of the specimens tempered at 500, 600 and 650 C. Tempering causes a maximum in Barkhausen noise vs. stress curve and minima in the field strength vs. stress curves. An increase in the impedimental force due to
345
Kameda, J.
38030 Cook, K.V.; McClung, R.W. Flaw density examinations of a clad boiling water reactor
C h a r a c t e r i z a t i o n of t e m p e r e d m a r t e n s i t e m i c r o s t r u c t u r e and embrittlement by acoustic a n d m a g n e t i c B a r k h a u s e n signal
p r e s s u r e vessel segment Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States), NUREG-CR-4860, 30 pp. (Apr. 1987) As part of the Oak Ridge National Laboratory's Heavy-Section Steel Technology Program, studies have been conducted to determine flaw density in a section of reactor pressure vessel cut from the Hope Creek Unit 2 vessel. This boiling water reactor vessel was never in service. One objective was to evaluate the approximate 0.7 by 3-m (2- by 10-ft) segment of the vessel provided using ultrasonic flaw detection methods performed with both ASME Code techniques and supplemental ultrasonic methods. A second objective was to evaluate the inner surface stainless steel cladding for cracks with a high sensitivity penetrant examination. Both objectives were successfully completed.
measurement Scripta Metallurgica, Vol. 22, No. 9, pp. 1487-1492 (Sep. 1988) It has been well recognized that ultrahigh strength alloy steels exhibit embrittlement when they are tempered in the temperature range from 300 to 400sup(o)C. This phenomenon is referred to as tempered martensite embrittlement and is attributed to the occurrence of intergranular and/or cleavage fracture. The fracture mode depends on the alloy composition and the impurity content of steels. The intergranular embrittlement is caused by two events: segregation of impurities such as sulfur and phosphorus, and carbide precipitation at grain boundaries. The intergranular segregation of impurities during austenitization weakens grain boundaries and the precipitation of carbides during tempering promotes the nucleation and propagation of cracks. The objective of this study is to evaluate nondestrnctively the characteristics of tempered martensite microstructure and embrittlement in an ultrahigh strength steel by measuring the two types of Barkhausen signals.
37933
J.P. The
Scruby, C.B.; Buttle, D,I.; Briggs, G.A.D.; Jakubovics, monitoring
of
stress
and
microstructure
by
magnetoacoustic emission United Kingdom Atomic Energy Authority, Harwell, AERE-R12782, 16 pp. (Oct. 1987) Magnetoacoustic emission (MAE) is generated by Iocalised magnetostrictive strains when domain walls move in ferromagnetic materials. MAE amplitude is a function of internal and applied stresses: however it is also dependent upon the microstructure so that these two effects must be separated for practical applications. Using the ratio of MAE at high and low fields, there is good sensitivity to stress in certain mild steel microstructures (e.g. ferritic/pearlitic) and much lower sensitivity to heat treatment. In rapidly cooled microstructures however, there is a much greater sensitivity to microstructure. In a separate study MAE has been used to monitor the subtle microstructural changes that accompany neutron irradiation of steels. It is concluded that MAE should he developed further as a nondestructive method for measuring stress and monitoring microstructure.
Karjalainen, L.P.; Rautioaho, R.H. Detection of fabrication sltresses by the Barkhansen noise method 38843
The Effects of Fabrication Related Stresses on Product Manufacture and Performance, Cambridge (United Kingdom), 23-25 Sep. 1985. pp. 149-161. Edited by J.F. Alder. The Welding Institute (1987) The high efficiency of the magnetic Barkhausen noise method for qualitative detection of stress changes due to welding, thermal and mechanical stress relief, machining and shot peening in structural steels is demonstrated. The importance of properly adjusting the strength of magnetization is pointed out. The steel composition, metallurgical structure, texture, dislocations and biaxiality of the stress field all affect the inherent Barkhansen noise level and its .,=tressdependence, so that calibration for accurate determination of stress magnitudes does not generally seem reasonable. Examples of the practical applications of the method are briefly outlined.
37930
38249 Ranjan, R. M i c r o s t r u c t u r a l characterization of ferromagnetic materials
Ranjan,R.
M i c r o s t r u c t n r a l c h a r a c t e r i z a t i o n of ferromagnetic m a t e r i a l s using magnetic NDE techniques Dissertation Abstracts International, Voi. 48, No. 4, p. 1129 (Oct. 1987) Magnetic NDE techniques, namely, the acoustic Barkhausen noise, the magnetic Barkhausen noise and the magnetic hysteresis curves, were simultaneously used for microstructural characterization of nickel and steels. Results showed that, in nickel, the non-180 deg domain wails interact more strongly with dislocations than the 180 deg domain walls. A study of the grain size effect on the magnetic and acoustic Barkhausen noises showed a great potential as a NDE grain size measurement tool. Moreover, the Barkhausen signals indicate that the 180 deg domain walls in nickel seem to have a stronger interaction with grain boundaries than the non-180 deg domain walls, as indicated by the acoustic Barkhausen signal. Based on the experimental observations, a theoretical model is being proposed to explain the grain size effect on the Barkhausen signals.
using magnetic NDE techniques Ames Laboratory, Ames, Iowa (United States), IS-T-1231, DE87010918, 117 pp. (Jun. 1987) Magnetic NDE techniques, namely, the acoustic Barkhausen noise, the magnetic Barkhausen noise and the magnetic hysteresis curves, were simultaneously used for microstrnctural characterization of nickel and steels. Results showed that, in nickel, the non-180 deg domain walls interact more strongly with dislocations t!han the 180 deg domain walls. A study of the grain size effect on the magnetic and acoustic Barkhausen noises showed a great potential as a NDE grain size measurement tool. Moreover, the Barkhausen signals indicate that the 180 deg domain walls in nickel seem to have a stronger interaction with grain boundaries than the non-180 deg domain walls, as indicated by the acoustic Barkhausen signal. Based on the experimental observations, a theoretical model is being proposed to explain the grain size effect on the Barkhansen signals. The model takes into account the density of magnetic domain walls and their initial velocity, with both quantities being strongly dependent on microstructure. The acoustic and magnetic Barkhausen noises were also found to he very sensitive to the change in carbide morphology.
Hetherington, M.G.; Jakubovics, J.P.; Szpunar, J.A.; Tanner, B.K. 37631
High-voltage L o r e n t z electron microscopy studies of d o m a i n s t r u c t u r e s a n d m a g n e t i z a t i o n processes in pearlitic steels Philosophical Magazine B, Voi. 56, No. 5, pp. 561-577 (Nov. 1987) Pearlitic steels with volume fractions of pearlite from 5 to 100% have been studied using a high-voltage electron microscope and by measuring the Barkhausen activity. The results indicate that the microstructural parameters that affect the coercivity most strongly are the volume fractions and grain sizes of ferrite and pearlite. In electron microscope studies it was observed that domain walls were particularly strongly pinned in cementite lamellae in pearlite grains. A simple model is derived from these observations, which correctly predicts the coercivity of a large number of steels.
38238 Buttle, D.I.; Scruby, C.B.; Briggs, G.A.D.; Jakubovics, J.P. The measurement of stress in steels of v a r y i n g m i c r o s t r u c t u r e by magnetoacoustic and B a r k h a u s e n emission Proceedings of the Royal Society of London Series A, Vol. 414, No. 1847, pp. 469-497 (1987) Magnetoacoustic emission (MAE) and Barkhausen emission (BE) have been measured as a function of applied magnetic field and tensile stress from mild-steel samples in a wide range of heat treatments, to develop a technique to measure stress without prior knowledge of the microstructure. The results are supplemented by measurements of magnetic coercivity and mechanical hardness. MAE is found to decrease with increasing applied stress, whereas the variation of BE is more complicated. The amplitudes of both MAE and BE, as well as the coercivity and hardness are also found to depend on the microstructure to varying degrees. The dependence of MAE and BE on magnetic field are discussed in terms of domain-wall nucleation and irreversible motion in ferri~te at higher fields, and irreversible wall motion through martensite or pearlite at lower fields. The results imply that MAE can be used alone to measure stress provided the general form of the microstructure is known; otherwise BE can he used as an additional technique to resolve any ambiguity.
37495 Rautioaho,R.; Karjalainen, P.; Moilanen, M. Stress response of B a r k h a u s e n noise in a t e m p e r e d C - M n steel Journal of Magnetism and Magnetic Materials, Vol. 68, No. 3, pp. 314- 320 (Sep. 1987) The dependence of Barkhausen noise on tensile stress is measured in a high strength vanadium microailoyed C-Mn steel after tempering at 200, 400, 500, 600 and 650 C. Simultaneously, the coercive force and two field parameters related to the magnetic reversal curve are recorded for some of the specimens tempered at 500, 600 and 650 C. Tempering causes a maximum in Barkhausen noise vs. stress curve and minima in the field strength vs. stress curves. An increase in the impedimental force due to
345