Magnetic Barkhausen Noise and Neutron Diffraction Techniques for the Study of Intergranular Residual Strains in Mild Steel

2004 ◽  
Author(s):  
Roxana Hutanu
Keyword(s):  
Neutron Diffraction ◽  
Mild Steel ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
Residual Strains

scholarly journals Study on the Mechanism and Application of Applying Magnetic Barkhausen Noise to Evaluate Dislocation Density and Plastic Deformation

2020 ◽  
Author(s):  
Xueliang Kang ◽  
Shiyun Dong ◽  
Hongbin Wang ◽  
Xiaoting Liu ◽  
Shixing Yan
Keyword(s):  
Plastic Deformation ◽  
Dislocation Density ◽  
Diffraction Method ◽  
Grain Morphology ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
X Ray Diffraction ◽  
X Ray ◽  
Texture Characteristics ◽  
Residual Strains

Seven specimens of 45 steel with different residual strains were prepared by homogeneous plastic tensile test. The microstructure of the specimens was observed by scanning electron microscopy and the texture characteristics of the specimens were studied by X-ray diffraction. The results showed that plastic deformation mainly leads to dislocation increment in the microstructure rather than obvious deformed grain morphology, texture and residual stress. Then the dislocation density of each sample was calculated by X-ray diffraction method. The MBN signals of the samples were tested by magnetic Barkhausen noise method and the corresponding RMS (root mean square) values were calculated. The results showed that the dislocation density increases and the RMS value decreases with the increase of plastic deformation magnitude, the phenomenon was explained deeply. By establishing the correlation between dislocation density and RMS value, it was found that there was a good linear relationship between dislocation density and RMS value. According to the formula provided by the fitting curve, the dislocation density can be predicted by measuring the RMS value of any degree of plastic deformation.

Variations in Stress Concentration Factors Near Simulated Corrosion Pits as Monitored by Magnetic Flux Leakage, Magnetic Barkhausen Noise and Neutron Diffraction

1998 ◽  
Author(s):  
L. Clapham ◽  
K. Mandal ◽  
R. Sabet-Sharghi ◽  
D. L. Atherton ◽  
T. Holden ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Magnetic Flux ◽  
Electrochemical Machining ◽  
Local Stress ◽  
Magnetic Flux Leakage ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
Stress Concentrations ◽  
Corrosion Pits ◽  
Flux Leakage

The conditions under which a pit defect is formed in a pipe can influence local stress concentrations which, in turn, affect the Magnetic Flux Leakage (MFL) signal. In this study MFL, Magnetic Barkhausen Noise (MBN) and neutron diffraction (ND) techniques are used to monitor and compare the local stress distributions surrounding simulated pits in plate and pipeline samples. Our study shows two important findings. Firstly, mechanically machining of simulated corrosion pits creates considerable machining stresses around the defect Conversely, electrochemical machining (ECM) produces no measurable residual stresses. Secondly, all three techniques indicate that, provided stresses are high enough hr produce local yielding, there are significant differences in local stress concentrations depending on whether the pit was electrochemically machined prior to stress application or while the sample was under stress. The latter case is more relevant to pipelines which corrode whilst in service since operating line pressures normally produce pipe wall hoop stresses of up to 70% yield strength.

scholarly journals Caution to Apply Magnetic Barkhausen Noise Method to Nondestructive Evaluation of Plastic Deformation in Some Ferromagnetic Materials

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Manru He ◽  
Takanori Matsumoto ◽  
Tetsuya Uchimoto ◽  
Toshiyuki Takagi ◽  
Hongen Chen ◽  
...  
Keyword(s):  
Nondestructive Evaluation ◽  
Residual Strain ◽  
Magnetic Domain ◽  
Ferromagnetic Materials ◽  
Barkhausen Noise ◽  
Loading History ◽  
Magnetic Barkhausen Noise ◽  
Final State ◽  
Domain Structures ◽  
Residual Strains

AbstractMagnetic Barkhausen Noise (MBN) method is known as an effective nondestructive evaluation (NDE) method for evaluation of residual stress in ferromagnetic materials. Some studies on the feasibility of the MBN method for NDE of residual strains were also conducted and found applicable. However, these studies are mainly focused on the state of residual strains which were introduced through a one-cycle-loading process. In practice, however, structures may suffer from an unpredictable and complicated loading history, i.e., the final state of plastic strain may be induced by several times of large loads. Whether the loading history has influences on MBN signals or not is of great importance for the practical application of the MBN method. In this paper, several ferromagnetic specimens with the same final state of residual strain but of different loading history were fabricated and inspected by using a MBN testing system. The experimental results reveal that the loading history has a significant influence on the detected MBN signals especially for a residual strain in range less than 1%, which doubts the feasibility to apply the MBN method simply in the practical environment. In addition, micro-observations on the magnetic domain structures of the plastic damaged specimens were also carried out to clarify the influence mechanism of loading history on the MBN signals.

scholarly journals Time-Response-Histogram-Based Feature of Magnetic Barkhausen Noise for Material Characterization Considering Influences of Grain and Grain Boundary under In Situ Tensile Test

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2350
Author(s):  
Jia Liu ◽  
Guiyun Tian ◽  
Bin Gao ◽  
Kun Zeng ◽  
Yongbing Xu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Tensile Stress ◽  
Material Properties ◽  
Ferromagnetic Material ◽  
Silicon Steel ◽  
Time Response ◽  
Barkhausen Noise ◽  
Time Interval ◽  
Magnetic Barkhausen Noise

Stress is the crucial factor of ferromagnetic material failure origin. However, the nondestructive test methods to analyze the ferromagnetic material properties’ inhomogeneity on the microscopic scale with stress have not been obtained so far. In this study, magnetic Barkhausen noise (MBN) signals on different silicon steel sheet locations under in situ tensile tests were detected by a high-spatial-resolution magnetic probe. The domain-wall (DW) motion, grain, and grain boundary were detected using a magneto-optical Kerr (MOKE) image. The time characteristic of DW motion and MBN signals on different locations was varied during elastic deformation. Therefore, a time-response histogram is proposed in this work to show different DW motions inside the grain and around the grain boundary under low tensile stress. In order to separate the variation of magnetic properties affected by the grain and grain boundary under low tensile stress corresponding to MBN excitation, time-division was carried out to extract the root-mean-square (RMS), mean, and peak in the optimized time interval. The time-response histogram of MBN evaluated the silicon steel sheet’s inhomogeneous material properties, and provided a theoretical and experimental reference for ferromagnetic material properties under stress.

Residual Stresses in Overlapping Friction Taper Stud Welds

2010 ◽  
Vol 652 ◽  
pp. 111-115 ◽  
Author(s):  
D.G. Hattingh ◽  
Axel Steuwer ◽  
M. Neil James ◽  
I.N. Wedderburn
Keyword(s):  
Solid State ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Creep Damage ◽  
Local Damage ◽  
Planar Defects ◽  
Repair Technique ◽  
Damage Repair ◽  
Stud Welding ◽  
Residual Strains

This paper presents microstructural, hardness and residual strain information for solid-state welds in creep-resistant Cr-Mo steel, made using the new local damage repair technique offered by friction taper stud welding (FTSW). The technique is suitable for making single welds to repair, for example, localised creep damage but can also be extended to deal with planar defects through the use of overlapping welds. Neutron diffraction was used to measure residual strains at a number of positions along a series of 5 overlapping FTS welds.

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

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