Barkhausen Noise Method Research Articles

Influence of the process parameters and forces on the bore sub-surface zone in BTA deep-hole drilling of AISI 4140 and AISI 304 L

The relationship between the cutting speed, the feed, the resulting process forces during the BTA deep hole-drilling process and the functional properties in the bore sub-surface zone of AISI 4140 and AISI 304 L is analysed. Due to the asymmetric design of the drill head radial forces occur which are supported through guide pads on bore surface. The result is an inner force flow inside the tool that affects a self-guiding effect during the drilling process. Due to this process the bore (sub-)surface zone is impinged with thermal and mechanical loads resulting in hardening, structural changes in microstructure and the occurrence of residual stresses, which can influence the fatigue strength, service life or reliability of the part. Residual stresses are measured using the magnetic Barkhausen noise method. Understanding the relationship between the process forces and functional properties in the bore sub-surface zone is essential for a following process control in order to generate defined bore sub-surface zones.

Finite Element Analysis and Ultrasonic Evaluation of Stresses in Q345 Plates

This paper investigates and demonstrates the nondestructive capability of ultrasonic waves and magnetic Barkhausen noise (MBN) in stress evaluation of Q345 plates. A 10mm thick Q345 specimen was subject to a concentrated load by a stressing jack, known as three-point bending test. A finite element model of Q345 plate was established to verify the experimental results. The stresses have been measured by three nondestructive evaluation methods including ultrasonic techniques, magnetic Barkhausen noise method and strain gauge method. This paper gives the details of development of ultrasonic longitudinal critically refracted (LCR) wave based technique for stress measurement. The results show great agreement between finite element and three stress measurements which are accomplished nondestructively.

Detailed Barkhausen noise and microscopy characterization of Jominy end-quench test sample of CF53 steel

Jominy end-quench test samples from CF53 were used for studying the relationship of microstructural changes with the magnetic Barkhausen noise (BN) response.As the Barkhausen noise method is sensitive to both stress and microstructural state, it can be applied for material characterization. This study presents observations from BN measurements with different sensors and from different locations (as-quenched and ground) on the sample surface. Detailed microstructural characterization with a scanning electron microscope and a transmission electron microscope was carried out to correlate the BN responses with the microstructural features. In addition, residual stresses were measured by X-ray diffraction. The results indicate that the ground surface displayed mainly the effect of the grinding compressive stress state, while the as-quenched surface had variations due to higher microstructure sensitivity. An important finding of the results was that the sensitivity of BN to different surface conditions varied: The BN response in the ground area was mainly generated by both the residual stress and the microstructural effect, whereas for the as-quenched surface the microstructural effect was more evident.

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

Magnetic 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.

Use of Time-Dependent Multispectral Representation of Magnetic Barkhausen Noise Signals for the Needs of Non-Destructive Evaluation of Steel Materials.

Due to the existing relationship between microstructural properties and magnetic ones of the ferromagnetic materials, the application potential of the magnetic Barkhausen noise (BN) method to non-destructive testing is constantly growing. However, the stochastic nature of the Barkhausen effect requires the use of advanced signal processing methods. Recently, the need to apply time-frequency (TF) transformations to the processing of BN signals arose. However, various TF methods have been used in the majority of cases for qualitative signal conditioning and no extensive analysis of TF-based information has been conducted so far. Therefore, in this paper, the wide analysis of BN TF representation was carried out. Considering the properties of TF transformations, the Short-Time Fourier Transform (STFT) was used. A procedure for definition of the envelopes of the TF characteristic was proposed. To verify the quality of extracted features, an analysis was performed on the basis of BN signals acquired during stress loading experiments of steel elements. First, the preliminary experiments were processed for various parameters of the measuring system and calculation procedures. The feature extraction procedure was performed for different modes of TF representations. Finally, the distributions of TF features over the loading stages are presented and their information content was validated using commonly used features derived from time T and frequency F domains.

Prediction of the hardness of X12m using Barkhausen noise and component analysis methods

Abstract Barkhausen noise (BN) generated by the stochastic movements of domain walls is one of the most popular non-destructive testing signal. To measure the property of material, the feature(s) extracted from BN signal has been focused by the existing studies. Although the physical characteristic of several BN features could be proven, many features used in the BN-related works are prone to being interfered by the noise, temperature and other measurement conditions. In this paper, to build a stable and unified representation of BN signal, a novel BN feature extraction and hardness prediction method is proposed. The proposed method includes BN-reconstructed AR model, modified slow feature analysis for fusing different AR-order signal and discriminant incoherent component analysis for the hardness prediction. In the experiment, all potential parameters involved in our method were tested to show the relationship between the parameters and hardness prediction accuracy. Then our proposed method was compared with other component-analysis-based methods and self-defined isolated-feature-based prediction methods. The experimental result implies that our proposed method outperforms other methods, including features generated by component analysis methods and the combination of conventional BN features.

Review of Residual Stress Measurement by Magnetic Barkhausen Noise Technique

Abstract Determination of residual stress state is important for quality, integrity, and service performance of the components and structures. Almost all manufacturing processes cause considerable amounts of residual stress; thus, any process or product design ignoring it involves a risk for distortion or early failure. Among the existing methods, the magnetic Barkhausen noise method has been gaining attention for measuring residual stresses nondestructively in ferromagnetic materials. It is sensitive to the interactions between the magnetic structure and microstructure or residual stress fields. So far, successful qualitative results have been obtained for monitoring the residual stress variations on the surfaces of the components manufactured by various processes. However, some challenging tasks exist, such as obtaining reliable quantitative results when residual stresses and microstructure change at the same time or extracting depth-specific information. This article reviews the studies for the measurement of residual stress by magnetic Barkhausen noise method, particularly focusing on the processes widely used in industry, namely shot peening and welding.

Non-destructive Flaw Mapping of Steel Surfaces by the Continuous Magnetic Barkhausen Noise Method: Detection of Plastic Deformation

This paper reports the use of a non-destructive scanning technique to identify plastic deformation defects generated in steel. The technique is based on measurement of continuous magnetic Barkhausen noise (CMBN). In the experiments described here, surfaces with plastic deformations produced by crushing stresses in a 1070 steel are scanned, and the influence of probe configuration, coil type, scanner speed, applied magnetic field and the frequency band used for the analysis on the effectiveness of the technique is studied. A moving smoothing window based on a second order statistical moment is used to analyze the time signal. The results show that the method can detect the position of plastic deformation defects and distinguish between their amplitudes.

Microstructural Magnetic Characterization of Annealed Non-Oriented Electrical Steel

The present paper investigates the utilization of the magnetic Barkhausen noise and magnetic permeability methods for the nondestructive characterization of annealed non-oriented electrical steel samples which were isothermally annealed in a wide range of temperatures (400°C – 950°C) and subsequently cooled in air. The resulting magnetic properties were compared with the microstructural changes occurring during annealing.

Experimental Investigation on the Crack Closure Phenomenon Using Barkhausen Noise Method

This paper presents an experimental investigation on a middle tension (MT) specimen made of a low carbon structural steel subjected to cyclic loading. The work was aimed to assess the effectiveness of Barkhausen Noise method in detecting the crack closure phenomenon. The Influence of probe orientation and position ahead the crack tip was examined, in order to optimize the magnetic measurements. A filtering procedure was also used to treat the Barkhausen Noise signal. A procedure was proposed to determine the crack-opening load from it. On the same specimen, some strain gauge measurements were carried out to determine the crack-opening load by the local compliance method. The results showed a good agreement of the results obtained with the two experimental techniques.

Non-destructive scanning for applied stress by the continuous magnetic Barkhausen noise method

This paper reports the use of a non-destructive continuous magnetic Barkhausen noise technique to detect applied stress on steel surfaces. The stress profile generated in a sample of 1070 steel subjected to a three-point bending test is analyzed. The influence of different parameters such as pickup coil type, scanner speed, applied magnetic field and frequency band analyzed on the effectiveness of the technique is investigated. A moving smoothing window based on a second-order statistical moment is used to analyze the time signal. The findings show that the technique can be used to detect applied stress profiles.

A RSM-based predictive model to characterize heat treating parameters of D2 steel using combined Barkhausen noise and hysteresis loop methods

Austenitizing and tempering temperatures are the effective characteristics in heat treating process of AISI D2 tool steel. Therefore, controlling them enables the heat treatment process to be designed more accurately which results in more balanced mechanical properties. The aim of this work is to develop a multiresponse predictive model that enables finding these characteristics based on nondestructive tests by a set of parameters of the magnetic Barkhausen noise technique and hysteresis loop method. To produce various microstructural changes, identical specimens from the AISI D2 steel sheet were austenitized in the range 1025–1130°C, for 30min, oil-quenched and finally tempered at various temperatures between 200°C and 650°C. A set of nondestructive data have been gathered based on general factorial design of experiments and used for training and testing the multiple response surface model. Finally, an optimization model has been proposed to achieve minimal error prediction. Results revealed that applying Barkhausen and hysteresis loop methods, simultaneously, coupling to the multiresponse model, has a potential to be used as a reliable and accurate nondestructive tool for predicting austenitizing and tempering temperatures (which, in turn, led to characterizing the microstructural changes) of the parts with unknown heat treating conditions.

EVALUATION OF STRESS IN STEEL STRUCTURES USING ELECTROMAGNETIC METHODS BASED ON UTILIZATION OF MICROSTRIP ANTENNA SENSOR AND MONITORING OF AC MAGNETIZATION PROCESS

In this paper the results of utilization of electromagnetic methods operating in low and high frequency range for evaluation of stress state and plastic deformation in steel elements are presented. In low frequency range Barkhausen noise and magnetic hysteresis loop method for evaluation of stress level and growth of plastic deformation changes were utilized. The methods allow to monitor parameters related to magnetization process under AC filed. Additionally in this paper the possibility of utilization of high frequency method for estimation of deformation extent (i.e. elongation) caused by stress will be presented. In this experiment the frequency response (the reflection coefficient S11) is measured. The strong relation of antennas resonant frequency to patch dimensions is utilized in order to obtain information about deformation of the sample.

Structure Investigation of the Constructional Steel St3ps after Argon-Arc Plasma Treatment

The plasma processing causes a change of a surface layer structure and characteristics of the surface layer of the material. During plasma processing the surface is subjected to ultrafast heating and cooling which causes a thin hardened layer, and the resulting non-equilibrium structure of the layer provides properties that are different from the properties of the base metal. Since transformations in alloys due to the ultrafast heating by highly concentrated energy flows are not sufficiently explored, the surface layer structural state and its properties are of a great practical and scientific interest. The article presents study results of the St3ps steel after surface hardening with plasma arc. To study the structure of steel, the author used the microanalysis, the magnetostructural Barkhausen Noise Method; residual stresses have been determined by the x-ray diffraction. The study revealed correlation between the processing mode, steel microstructure, residual stress values and the Barkhausen noise amplitude.

Stress Response of Magnetic Barkhausen Noise in Submarine Hull Steel: A Comparative Study

The development of magnetic Barkhausen noise methods for rapid detection of residual stress concentrations has implications for integrity assessment of submarine pressure hulls. However, the stress-response of Barkhausen noise in submarine hull steel, HY-80, is complicated by the influence of the material’s martensitic microstructure. The present work sheds light on the stress-dependent behavior of Barkhausen noise in HY-80 by comparing its signal characteristics with those of more common ferrite/pearlite steels. HY-80 and various ferrite/pearlite steel plates were uni-axially stressed up to and beyond the level for plastic deformation. Barkhausen noise measurements, performed using the same sensor under reproducible flux-controlled magnetization conditions, facilitated a direct comparison of material responses. Results showed that with the application of tensile stress, the Barkhausen noise signal of ferrite/pearlite steels linearly increased, reached a peak value and saturated in the elastic region. By contrast, HY-80 demonstrated a linear increase with tensile stress characterized by a transition from a lower to a seven times higher rate of change for stresses above 200 MPa up to its yield point. The different stress-response of HY-80 was attributed to its martensitic microstructure, which modifies the response of the domain structure under tensile stress conditions.

Detection of a milling-induced surface damage by the magnetic Barkhausen noise

The potential of the magnetic Barkhausen noise method for a non-destructive evaluation of the steel surface damage cased by milling was comprehensively investigated. A typical bearing steel was heat treated to three different hardnesses and then machined using the cutting tools with different degrees of the flank wear. The magnetic low-frequency measurements with a high reading depth were performed using a unique laboratory system providing a full control of the magnetization process. The high-frequency measurements were performed using a commercial Rollscan device. To study the induced magnetic anisotropy, the measurements were performed in two magnetization directions. In the feeding direction, the Barkhausen noise profiles showed a second high-field peak ascribed to an induced hardened surface layer, a so-called white layer. The most reliable results were obtained with the controlled waveform of the surface magnetic field measured directly by Hall sensors. In the perpendicular rotation direction, formation of the preferentially oriented matrix resulted in an enormously high Barkhausen noise activity. Based on these results, new magnetic parameters were proposed for the non-destructive evaluation of the white layer formation.

Correlation of magnetic properties with deformation in electrical steels

This paper investigates the utilization of magnetic Barkhausen Noise (MBN) and hysteresis loops methods for the non-destructive characterization of deformed electrical steel samples. For this reason electrical steel samples were subjected to uniaxial tensile tests on elastic and plastic region of deformations. Both the MBN and hysteresis loops were measured. The results shown a strong degradation of the magnetic properties on plastically strains. This was attributed to the irreversible movement of the magnetic domain walls, due to the presence of high dislocation density. The resulting magnetic properties were further evaluated by examining the microstructure of the deformed samples by using scanning electron microscopy.

Evaluation of the Welding Zones’ Magnetic Anisotropy by Using Magnetic Barkhausen Noise

The present paper investigates the utilization of the magnetic Barkhausen noise method for the experimentally, nondestructive characterization of the magnetic anisotropy phenomenon, in a welded pipeline steel. The results shown that it is possible to distinguish the three welding zones in the curve of the anisotropy coefficient

An attempt of characterization of stress state in high carbon C68D steel wire rod by Barkhausen noise method

The paper presents preliminary tests of high carbon steel wire rods by the non-destructive Barkhausen method. Correlation between applied external stress to the wire rod and current sweep characteristics were observed. Some geometrical parameters of the shape of these characteristics corresponded to mechanical stress state were assigned. Obtained result can be used for more reliable estimation of residual stress state and quick comparison of residual stress level in wire rod after different production variants. Streszczenie. W artykule zaprezentowano wstepne badania walcowki ze stali wysokoweglowej za pomocą nieniszczącej metody Barkhausena. Zaobserwowano korelacje pomiedzy zadawanymi w walcowce naprezeniami a charakterystykami typu sweep. Pewne parametry geometryczne ksztaltu tych charakterystyk, korespondujące ze stanem naprezen mechanicznych, zostaly wyznaczone . Uzyskane rezultaty mogą byc pomocne dla bardziej wiarygodnej oceny stanu naprezen wlasnych i szybkiego porownywania ich poziomow w walcowce po roznych wariantach produkcji (Proba oceny stanu naprezen w walcowce zestali wysokoweglowej C68D za pomocą metody Barkhausena).

Review of railway track applications of Barkhausen noise and other magnetic testing methods

Review of railway track applications of Barkhausen noise and other magnetic testing methods