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AC magnetic properties of electrical steel sheets are generally evaluated under symmetrical alternating magnetization in the standard magnetic measurement. However, magnetizing conditions of electrical steel sheets in electromagnetic machines are not always symmetric and alternating magnetization. This paper presents a new measuring system for AC magnetic properties of electrical steel sheets under two-dimensional DC-biased magnetization and discusses the properties under DC-biased magnetization. [ABSTRACT FROM PUBLISHER]

Magnetic Barkhausen Noise (BN) is a useful parameter for analysing physical and micro structural properties of electrical steel. It is believed to be due to microscopic discontinuities in domain wall motion due to the presence of defects. Grain-oriented electrical steel has an insulating surface coating which provides a beneficial stress in the steel. BN is sensitive to changes in the surface condition of steels. Measurements have been carried out on strips of high permeability grain-oriented (HGO) and conventional grain-oriented (CGO) 3% silicon steels, at 50 Hz in the peak flux density range 8.0 mT to 1.0 T before and after chemical removal of the coatings. Coating removal from HGO and CGO materials increases BN at high and low fields. This can be explained in terms of widening of 180^\circ domains due to the release of coating stresses so that domain walls move further between pinning sites thereby generating higher rates of change of magnetisation which result in higher BN. In the coated materials, BN was found to be higher in HGO than in CGO at flux densities above around 0.2 T but the trend changes at lower flux densities because of grain size/misorientation effects. However, it is interesting to note that in the decoated material the BN is higher in HGO at all flux densities. Application of a 3 MPa tensile stress to the decoated samples caused the BN below 0.2 T to become higher in CGO than in HGO demonstrating that domain refinement due to coating stress and externally applied stress produce similar effects on BN. A significant correlation was found between the average velocities of domain wall movement and changes in BN at all the peak flux densities in the test materials. [ABSTRACT FROM PUBLISHER]

The influence of the tile angle of the [001] out of crystal surface \beta on iron loss improvement of 3 % Si steel single crystals was investigated. This iron loss improvement was caused by tensile stress effect of TiN coating and domain refinement. When \beta angle was less than 3 degrees, both eddy current loss and hysteresis loss decrease. Extremely low iron loss was obtained, when \beta angle equal to about 2 degrees. On the other hand, when \beta angle is more than 3 degrees, the hysteresis loss increased though the eddy current loss decreased by TiN coating. As a result, change in iron loss was small after TiN coating and domain refining. Therefore, it was clarified that the iron loss improving methods, such as domain refining and ultra-high tension coating, were effective especially in grain oriented electrical steel whose \beta angle is less than 3 degrees. [ABSTRACT FROM PUBLISHER]

Changes of magnetic and mechanical properties by high-temperature, isothermal agings were studied in a 12Cr-W steel. Results of coercivity, hysteresis loss, and Vickers hardness obtained from the aged specimen decreased with second order exponential functions of the aging time increased. These phenomena were analyzed using the scanning electron microscope, backscattered electron, and X-ray diffraction; from a microstructural viewpoint, the aging resulted in a coarsening of the tempered carbide (Cr23C6) and a formation of the Laves (Fe2W) phase. These microstructural changes are closely related with a reduction of the mechanical strength with the aging time. [ABSTRACT FROM PUBLISHER]

The simultaneous effects of the hot band grain size and cold reduction on the final grain structure, texture and magnetic properties of 3%Si steel were studied by variation of finishing temperature and hot band thickness during hot rolling, followed by cold rolling to final thickness and annealing in H2/N2 atmosphere. The results have shown that there is an optimum combination of hot band thickness and hot band grain size for maximum Eta/Gamma ratio and better magnetic properties (B50 and W1.5/60) after final annealing. For the thicker hot band, it was observed that higher finishing temperature, or larger hot band grain size, was necessary to achieve high Eta/Gamma and better magnetic properties. Too large hot band grain size, however, could result in smaller final grain size due to the intense nucleation on recrystallization in the shear bands and consequently poor core loss values. This behavior was explained based on the hot band grain structure and cold rolling effects on the texture evolution. [ABSTRACT FROM PUBLISHER]

Magnetic and magnetostrictive behaviors of magnetic materials are very sensitive to mechanical stress and especially to plastic deformation. A model based on the decomposition of a plastified material into mechanically hard and soft phases has been proposed. An appropriate experimental procedure is presented in order to validate the model. The magnetic and magnetostrictive behaviors of a dual-phase steel are carried out. Measurements are made at unloaded stress and under various applied stress to observe a recovery phenomenon predicted by the modeling. Experiments and modeling are compared. [ABSTRACT FROM PUBLISHER]

Abstract: We report results of minor B–H loop measurements on a highly neutron-irradiated A533B-type reactor pressure vessel steel. A minor-loop coefficient, which is a sensitive indicator of internal stress, changes with neutron fluence, but depends on relative orientation to the rolling direction in the low fluence regime. At a higher fluence of ∼10×1023 m−2, on the other hand, an anomalous increase of the coefficient was detected irrespective of the orientation. The results were interpreted as due to competing irradiation mechanisms of the formation of Cu-rich precipitates, recovery process, and the formation of late-blooming Mn–Ni–Si-rich clusters. [Copyright &y& Elsevier]

Abstract: Scaling laws in dynamical magnetic minor hysteresis loops have been investigated in the magnetizing frequency range of 0.05–300Hz for various steels including Cr–Mo–V steel subjected to creep, cold rolled steels, and plastically deformed Ni. Although scaling laws in the medium magnetization range found previously fail in the high magnetization frequency regime owing to a significant contribution of eddy currents, a scaling power law of the relation between remanence and remanence work of minor loops, associated with a constant exponent of approximately 1.9, holds true in a very low magnetization regime, irrespective of magnetization frequency and investigated materials. The coefficient of the law is proportionally related to Vickers hardness over the wide frequency range. These observations demonstrate that the scaling analysis of dynamical minor loops enables us to evaluate materials degradation in a short measurement time with low measurement field and high sensitivity to defect density. [Copyright &y& Elsevier]

To describe the vector magnetic hysteresis phenomenon of electrical steel sheets, an improved vector Jiles-Atherton hysteresis model is presented. The proposed model is developed based on Berqvist model. First, the anhysteretic magnetization function is improved by modifying the model parameters according to the excitation direction. By this, the modeling results are accurate under different alternating and nonsaturated rotating excitations. Furthermore, to model the magnetic property under saturated rotating excitations accurately, the proposed model is extended by modifying the model parameters according to the measured data. The proposed model is validated through comparisons between modeling and measured results under different alternating and rotating excitations. [ABSTRACT FROM AUTHOR]

Abstract: The austenite–ferrite superduplex stainless steel (SDSS) is essentially an Fe–Cr–Ni alloy to which additional elements (e.g. Mo, Mn, Si, Cu, C, P, S) were added so as to confer additional advantageous characteristics such as higher mechanical strength and resistance to corrosion. Many of its applications require the process of rolling which, due to the two-phase character, induces a marked texturing, elongation of grains, and directional ordering in each of the constituent phases. This, in turn, imprints a strong anisotropic features in the mechanical, magnetic, and other properties. Using various experimental techniques, such as magnetization and ac susceptibility, this work investigated the induced magnetic anisotropy. An easy axis (parallel to the rolling direction) anisotropy was observed. The nature of the magnetic anisotropy, manifested during low and high applied magnetic fields, will be discussed in terms of the combined influences of two main anisotropies, namely shape anisotropy (arising from demagnetizing forces) and texture anisotropy (arising from the induced preferred orientation). [Copyright &y& Elsevier]

Abstract: From practical point of view, determining the decarburizing depth is important in quality control of steel parts as it has undesirable effects on the mechanical properties such as hardness, wear and fatigue resistance. Traditional destructive methods of determining the depth of decarburized layer include metallographic and hardness test which are time-consuming and costly. Since response to eddy current is sensitive to chemical composition as well as microstructure of the material under consideration, the non-destructive method can be used in determining the depth of the decarburized layer in steel parts. It is mainly due to the difference in the microstructures, and as a result, in the magnetic properties of the decarburized layer with other parts of the specimen. In the present study at the first step, the magnetic properties of decarburized carbon steel bars (0.45wt.% C) were evaluated using an electromagnetic sensor and correlated with the microstructure changes from surface to the core of the sample. At the second step the steel bars were held in 900°C for different period of times and the depth of decarburizing layers were measured using hardness testing. Finally, the non-destructive eddy current technique was used and the response of test samples to the induction current including primary and secondary voltages, normalized impedance, phase angle and harmonic analysis parameters were investigated. Results show an acceptable accuracy in comparison to the destructive method. [Copyright &y& Elsevier]

The influence of heat treatment modes (hardening and aging) and uniaxial tension on the structure and magnetic properties of carbonless high-strength corrosion-resistant steel 03Kh20AG11N7M2 containing 0.4% N and having a structure of austenite + 10% 0-ferrite is studied. The coercive force, the residual induction, and the magnetization of a specimen in a maximum applied field are detected under the action of a load over the whole of the stress - strain curve until the formation of a neck. The magnetization and the coercive force of the steel increase under the action of plastic deformation. The deformation behavior of the magnetic characteristics is discussed with allowance for the special features of the structural state of the material. [ABSTRACT FROM AUTHOR]

The evolution of the magnetic characteristics of case-hardened Steel 20 under the influence of elasto-plastic tensile, compressive, and torsional strains is analyzed. The field dependence of the differential magnetic permeability is shown to reflect a three-layer nature of the obtained micro-structure: a hardened surface layer, a transition zone, and a ferrite-pearlite core. It is proposed to evaluate the level of the applied stresses on the basis of the peak field and the height of the differential magnetic permeability peaks of corresponding layers of the case-hardened steel. [ABSTRACT FROM AUTHOR]

The effects of flaws in the insulating coating of an electric anisotropic steel, which are formed during its laser processing in accordance with the optimal technology used in industry, on the elastic tensile stresses induced in the metal by the coating and magnetic properties were investigated. It was shown that discontinuity of insulating coating at the location of laser-beam action does not lead to a decrease in elastic tensile stresses and deterioration of magnetic properties of steel. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic behaviour and martensitic transformation at cryogenic temperatures (down to 4K) of the austenite phase of the duplex stainless steel (DSS), 7MoPLUS, were studied. As regards the prediction of Neel temperature, the empirical expressions for austenitic stainless steels are not applicable to the austenite phase of 7MoPLUS, although the composition of the austenite phase falls within the composition ranges within which the expressions were developed. Regarding the prediction of martensitic point Ms, the applicability of ‘old’ and recently developed expressions has been examined. The recently developed expressions, which take into account more alloying elements and their interactions, are not suitable for the austenite phase of 7MoPLUS. But for the ‘old’, simpler expressions, they seem to be valid in the sense that they all predict high stability of the austenite phase. Results obtained from 7MoPLUS were qualitatively the same as those obtained from another DSS, designated as 2205. Reasons for the applicability and inapplicability of these empirical expressions are suggested. [Copyright &y& Elsevier]

CYCIAE-100, a 100 MeV H-cyclotron under construction at China Institute of Atomic Energy, is a compact H-cyclotron. Since its upper/bottom and return yokes are each made of a casting steel of large dimension (with final dimension of 6160 mm in diameter and weight of 140 tons each piece), special attention has to be paid to the annealing procedure to insure the magnetic properties of this kind of large scale casting steel pieces with high purity. First, this paper presents an overview of annealing strategies to improve the magnetic properties of large scale casting steel. Then an estimation of heating time during annealing procedure has been made by FEM simulation based on the current status of annealing facility in China and has been indirectly verified by a rule of thumb from the results in TRIUMF design note. Based on that as well as on a close collaboration with CITIC HMC, the manufacturer of large casting steel mill, an agreement on detailed annealing procedure has been reached and issued for production of large casting steel for CYCIAE-100. The results from the practice have been obtained and the detail procedure will be presented in this paper as well. [ABSTRACT FROM AUTHOR]

Abstract: 5Cr–0.5Mo steel having initial bainitic microstructure has been aged at 600°C for 5000h and subjected to creep at 600°C/60MPa. At different lengths of time the tests were interrupted for magnetic measurement using magnetic Barkhausen emissions (MBE) and magnetic hysteresis loop (MHL) techniques. Composition, morphology and distribution of carbides were studied using scanning electron microscopy (SEM). Magnetic softness was observed in the material up to 1600h of ageing due to the decrease in pinning density for the coarsening of carbides by accumulation of large number of finer carbides. At higher ageing periods the demagnetizing field offered by the large massive carbides causes magnetic hardening. During creep test since the material has been normalized at 50h of creep test also the structural change in creep test is accelerated, the magnetic softening for the interstitial carbon migration to the grain boundary and stress relaxation has removed in such early periods of ageing. When the carbides started coarsening the number density of the carbides decreased and inter-carbide distance increased which enhances the magnetic softening in the material in the secondary stage of creep. Formation of massive carbides and micro voids at the late tertiary stage of creep offers demagnetizing field causes magnetic hardening before failure of the material. [Copyright &y& Elsevier]

Abstract: For investigating the magnetic abnormality influenced by stress in ferromagnetic materials, static tension tests on a case-hardened steel were carried out. Different loads, which covered tensile elastic loads up to plastic deformation and break, were applied. Meanwhile, the normal component of magnetic flux leakage, H p(y), was measured by metal magnetic memory testing. The results indicate that H p(y) values change with the tensile loads and positions. There exists a relationship between k, which is the inclination of the linear amplitude-locus magnetic flux leakage curve, and static tension load. A simple model is derived. Additionally, the mechanism of the magnetic memory effect can be explained by the theory of the interaction between dislocations and domains. The research provides the potential possibility of quantitative inspection for metal magnetic memory testing. [Copyright &y& Elsevier]

IEC TC 68 is the standards committee which prepares international standards relating to magnetic alloys and steels. The committee works within the framework of the IEC and specializes in producing documents which standardize the specifications that apply to these materials and the measurement procedures for the relevant magnetic and physical properties. [ABSTRACT FROM AUTHOR]

The magnetic Barkhausen noise (MBN) in JRQ reference steel was measured under varying magnetization rate. The scaling properties of the avalanche size distribution were determined experimentally as a function of the excitation frequency. We have found that the exponent decreases and the scaling region extends as the excitation frequency increases in accordance with theoretical expectations. The average avalanche energy, size, and frequency were found to have power law dependence on the excitation rate. The temporal analysis has shown that the MBN noise generation starts earlier and develops a more symmetric character with the increase of the excitation frequency. These changes with the excitation rate can not be accounted for only by the overlap of individual MBN avalanches, but reveal a change of the dynamics of the MBN process. [ABSTRACT FROM AUTHOR]

Abstract: Case depth measurements of surface-hardened steel parts are important for quality control. Here, the magnetic properties of two sets of carefully characterized 25-mm-diameter case-hardened steel rods were studied with the aim of developing new methods to evaluate the case depth nondestructively. Induction-hardened 4140 steel and carburized 8620 steel rods were studied. Each set contained control samples (heat-treated but not surface-hardened) and samples hardened to three different nominal depths. After fabrication, the microhardness profiles of the rods were measured and the data analyzed to obtain the mid-hardness depth in each case. These measurements were compared with optical micrographs that reveal the microstructure of the samples as a function of depth below the surface. By the analysis of measured magnetization curves and hysteresis loops, the differential permeability and saturation magnetization of the rods were extracted. It was found that differential permeability increases with increasing case depth at a certain strength of the applied field (1350–1450A/m) for both hardening mechanisms, but only significantly for induction-hardened rods. Saturation magnetization was evaluated using the ‘law of approach’ and was observed to decrease as the depth of case hardening increases, for both induction-hardened and carburized steel rods. The observed behavior is described adequately by a simple model in which for the rod is represented as a volume-weighted sum of saturation magnetization values in the core and in the surface layer. [Copyright &y& Elsevier]

Abstract: In geomagnetic field, a series of tensile experiments on the low-carbon steel sticks were carried out. A special homemade detector was used to measure the magnetic gradient on the material surface. The results showed that the relationship between the magnetic gradient and the stress varied with different conditions of measurement. There was no obvious correlation between the magnetic gradient and the tensile stress if the sample remained on the material test machine. If the sample was taken off from the machine, the measured magnetic gradient was linear with the prior maximum stress. In Nanjing, PR China, a place of 32°N latitude, the slope of the linear relationship was about 67(uT/m)/MPa. This offered a new method of non-destructive stress testing by measuring the magnetic gradient on the ferromagnetic component surface. The prior maximum applied stress of the sample could be tested by measuring the present surface magnetic gradient. Actually this phenomenon was the metal magnetic memory (MMM). The magnetic gradient near the stress concentration zone of the sample, the necking point, was much larger than other area. Thus, the hidden damage in the ferromagnetic component could be detected early by measuring the magnetic gradient distribution on its surface. In addition, the magnetic memory signal gradually weakened as the sample was taken off and laid aside. Therefore, it was effective for a given period of time to detect the stress or stress concentration based on the MMM testing. [Copyright &y& Elsevier]

Abstract: The magnetic response of AISI 304L and AISI 316L obtained through powder metallurgy and sintered in nitrogen were studied. AISI 304L sintered in nitrogen showed a ferromagnetic behaviour in as-sintered state while AISI 316L was paramagnetic. After solution annealing both were paramagnetic. Magnetic behaviour was analysed by using a vibrating sample magnetometer, a magnetic ferritscope and magnetic etching. A microstructural characterization was performed by means of optical metallography, X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDS). Some samples when needed were submitted to aged heat treatments at 675 and 875°C for 90min, 4, 6, 8 or 48h. The main microstructural feature found was the presence of a lamellar constituent formed by nitride precipitates and an interlamellar matrix of austenite and/or ferrite. The abnormal magnetic response was explained based on this. [Copyright &y& Elsevier]

Abstract: Three series of samples of low-carbon steel were investigated by the method of magnetic adaptive testing (MAT). The samples were plastically deformed by cold rolling to five consecutive stages of deformation. Samples in one series were magnetically closed, those in the other two series were magnetically open. The presented results of MAT – typical by its low required magnetization of the samples – show highly sensitive and reliable correlation with plastic deformation and as a consequence also with mechanical embrittlement of the investigated material, regardless of the sample shape. [Copyright &y& Elsevier]

Attachable transducers were used to measure the demagnetizing current, which is proportional to the coercive force, and Barkhausen noise parameters for steel 45 specimens depending on the degree of their plastic deformation in measuring the magnitudes along and perpendicular to the tension direction. The demagnetizing current measured along the preliminary tension direction was shown to increase monotonically; the rate of its changes is maximal at the initial stage of plastic deformation. The demagnetizing current measured perpendicular to the applied tension direction also increases monotonically but within a narrower range. Near local inhomogeneities formed during the deformation, substantial changes in the coercive force and Barkhausen noise take place. The results obtained are explained on the basis of the current concept of the anisotropy of internal stresses in preliminarily plastically deformed materials. [ABSTRACT FROM AUTHOR]

Abstract: Magnetoelastic properties of materials are strongly influenced by changes of the dislocation structure that take place during the process of plastic deformation. Such changes can be used as a basis for a method of nondestructive evaluation (NDE) of the deformation level. So far, various methods, based on magnetic hysteresis loop properties as well as on the Barkhausen effect (BE), have been proposed. In the paper, the results obtained with the help of the abovementioned methods are compared with the results of the magnetoacoustic emission (MAE) signal measurements. The MAE signal is relatively easy to implement as a nondestructive method and unlike the BE effect signal gives information about the whole magnetized volume. [Copyright &y& Elsevier]

Abstract: The magnetic properties of ten types of ferritic and martensitic stainless steels have been measured at room temperature and at 77K. The steel samples studied were in the annealed state as received from the manufacturer. Our room temperature measurements indicate significantly harder magnetic properties than those quoted in the ASM International Handbook, which studied fully annealed stainless steel samples. Despite having harder magnetic properties than fully annealed steels some of the as-received steels still display soft magnetic properties adequate for magnetic applications. The carbon content of the steels was found to affect the permeability and coercive force, with lower-carbon steels displaying significantly higher permeability and lower coercive force. The decrease in coercive force with reduced carbon content is attributed to fewer carbide inclusions which inhibit domain wall motion. Cooling to 77K resulted in harder magnetic properties. Averaged over the ten steels tested the maximum permeability decreased by 8%, the coercive force increased by 14%, and the residual and saturation flux densities increased by 4% and 3%, respectively. The change in coercive force when cooled is comparable to the theoretical prediction for iron, based on a model of domain wall motion inhibited by inclusions. The modest changes of the magnetic properties indicate that the stainless steels can still be used in magnetic applications at very low temperatures. [Copyright &y& Elsevier]

The paper analyses the properties of deep-drawing sheets of three grades (Re = 320 to 475 MPa), surface-treated with hot-dip galvanizing, made of microalloyed steels. Deformation properties are assessed using tensile tests, technological Erichsen or cupping tests. These characteristics, as well as the behaviour of the surface layer, are also investigated under dynamic conditions (modified Erichsen test using a drop tester), or using flat bending fatigue tests. Using microscopic analysis the deformation properties of the surface layer are evaluated. The results show the compactness of the surface layer, high deformation characteristics, as well as fatigue properties of the investigated deep-drawing materials, suitable for application in the automotive industry. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic properties of nonoriented electrical steels are influenced by the grain size and crystallographic texture. The technologies used to control the grain size in nonoriented electrical steels are approaching their limits. However, there is still some room for improvement of the magnetic properties through texture control. Hot-band annealing is known to be one of the most effective processing stages for texture modification. In this study, two types of initial grain sizes prior to cold rolling are obtained by different hot-band annealing. The effect of initial grain size on texture evolution and magnetic properties in nonoriented electrical steels containing 2% Si is examined. The specimens having different initial grain sizes have significantly different textures in the cold-rolled state and the annealed state. During the recrystallization stage, new grains formed in the coarse-grained specimens have stronger Goss but weaker γ-fibre texture than those in the fine-grained specimens. During the grain growth after complete recrystallization, the coarse-grained specimens still have weaker γ-fibre texture than the fine-grained specimens. The magnetic induction of the coarse-grained specimens is always higher at the same temperature than that of the fine-grained specimens. The core loss of the coarse-grained specimens is lower at the same temperature than that of fine-grained specimens. However, the improvement of the core loss becomes less pronounced as the annealing temperature increases. [Copyright &y& Elsevier]

Abstract: The austenitic stainless steel 316 Low Vacuum Melting is a material that is widely used in biomedical applications, particularly for bone substitution or repair. Sandblasting is commonly used as surface modification for biomaterials to obtain better mechanical fixation of the prosthesis. However the microstructural changes beneath the surface associated with this modification as well as other physical properties are not well known. In this work, the results for microstructural, magnetic and mechanical features of the sandblasted austenitic steels 316LVM subsurface are analyzed for the first time. [Copyright &y& Elsevier]

Abstract: An experimental investigation was carried out to study the effect of stresses that approach and exceed the yield point, on the magnetic properties of ground samples of medium carbon steel upon surface grinding. The observed magnetic behaviour included magnetic Barkhausen emission measurements, characteristics changes in the shape of hysteresis loop and magnetic properties derived from hysteresis loop. Relation between Barkhausen Noise (BN) parameters and other magnetic properties with stress have been discussed in term of degree of plastic deformation. It was observed that peak of BN signal, saturation magnetization and permeability derived from hysteresis loop depend to some extent on residual stress and degree of plastic deformation while other magnetic properties obtained from BN profile and hysteresis loop are stress insensitive. X-ray diffraction (XRD), metallographic study and microhardness measurement of ground samples have been undertaken to confirm the results obtained by analysis of magnetic parameters. [Copyright &y& Elsevier]

A potential online nondestructive method using a multifrequency electromagnetic (EM) sensor to measure the decarburization of steels has been proposed and tested. Online (hot) testing was simulated, using composite samples comprised of a 316 stainless steel (paramagnetic) core and a surrounding tube of ferritic steel (ferromagnetic), with thicknesses between 100 and 600 μm. The sensor can detect the decarburization and quantify the depth. Offline (cold) measurement of decarburized high-carbon steel rods was also carried out and compared with the online measurement. The relationship between the sensor output and the decarburized layer type/thickness has been modeled using finite element methods (FEMs). [ABSTRACT FROM AUTHOR]

The effect of modes of ion-beam nitriding on the structure, microhardness, wear resistance, and magnetic properties of diffusion layer on typical austenitic stainless steel 12Kh18N10T is studied. Optimum modes of ion-beam nitriding ensuring maximum microhardness and wear resistance of the irradiated surface are determined. The nitriding temperature, the microhardness of the surface, and the signals of the overlaid magnetic and electromagnetic transducers are shown to be related. The dependences obtained are explained and recommendations are given on their use for the nondestructive check of parameters of the nitrided layer. [ABSTRACT FROM AUTHOR]

In this paper, stress and fatigue-loaded ferromagnetic steel samples were evaluated using three different remanent flux leakage transducers. Giant magnetoresistive sensors were used as the pickup elements. Each transducer has its own integrated local magnetizing section, which allows us to magnetize the tested material in different directions. The defect detection dependency on angle, at which it occurs to the magnetizing field and sensing element, is minimized by gathering and then integrating the information from transducers. The performance of the transducers was verified using a steel plate (S355J2G3) with electro-discharge machined notches. Further experiments were carried out using fatigue and stress-loaded steel samples. [ABSTRACT FROM AUTHOR]

The two-dimensional vector magnetic properties are proposed as a method to express the magnetic anisotropy and iron loss precisely by using the relationship between the flux density vector and the magnetic field strength vector. The E&S modeling [6] and the E&SS modeling [7–9] have enabled the representation of the two-dimensional vector magnetic properties in FEM calculations. However, the calculated flux density waveform at each element has a phase difference depending on the excitation condition. In this paper, we have improved the E&SS modeling to solve the magnetic field problems under any exciting condition. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 1–9, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20446 [ABSTRACT FROM AUTHOR]

The magnetic properties and hardness of a Ni–Co–Mo–Ti maraging steel 300 grade were measured as function of aging temperature. The austenite and martensite phase quantifications in the different heat treatment conditions were carried out by X-ray diffraction using direct comparison method. The behavior of the hardening, magnetization saturation and coercive force against aging temperature and time were explained taking into account the variation of austenite volume fraction with aging time and temperature. [ABSTRACT FROM AUTHOR]

The effect of thermal aging and electron irradiation on the micro-structure and magnetic properties of SQV2A steels are investigated in this study. The micro-structure variation is observed by transmission electron microscopy and the magnetic properties, such as hysteresis loops, are measured. Characteristic features are analyzed and the micro-structural dependence of the magnetic properties is investigated. [ABSTRACT FROM AUTHOR]

It is shown that, during discussion of the mechanism reliable for formation of the coercive force in high-carbon steel, in addition to the interaction between the domain walls and weakly magnetic cementite inclusions, the contribution from the cementite’s magnetic hardness should be considered. With the use of the temperature dependence of the coercive force in deformed and annealed specimens, the contribution of each of the considered mechanisms to the specimens’ coercive force is estimated. [ABSTRACT FROM AUTHOR]

Abstract: The effect of magnetic field with different intensities on fatigue life of AISI 4140 steel has been investigated. For this purpose, unnotched and notched specimens were prepared from AISI 4140 steel. It was obtained that when the magnetic field especially was applied to the specimens at the stage of fatigue crack initiation, the fatigue life improved by reason of delaying formation time of slip bands due to regular direction and distribution of magnetic domains. And, it was observed that magnetic field was applied from the beginning of fatigue test up to occur the fatigue fracture, it was detrimental on the fatigue life because of over heating of the specimens. [Copyright &y& Elsevier]

In order to investigate the detection of martensite phase in deformed austenitic stainless steel, magnetic properties were examined by means of super conducting quantum interface device (SQUID) and vibrating sample magnetometer (VSM) techniques. Stainless steel specimens were rolled at room temperature with 15 to 55% reduction in thickness. Results indicate that the magnetic properties of stainless steel were sensitive to percent reduction in thickness and micro structural condition of stainless steel. It was found that saturation magnetization, amount of martensite and hardness increased whereas, coercive force and remanence ratio decreased with increasing percent reduction in thickness. The saturation magnetization depends mainly on amount of martensite, while the coercive force and remanence depends mostly on shape and distribution of martensite phase. [ABSTRACT FROM AUTHOR]

The mechanical and magnetic properties of 50KhGFA laminated spring steel are investigated in different regimes of the quenching and tempering temperatures. It is shown that the quality of heat treatment of this steel cannot be tested using any standard magnetic characteristic. It is proposed to test the mechanical properties of 50KhGFA steel by measuring the amplitude of pulses driven a magnetized product into the demagnetized state or using the gradient of the remanent magnetization field after pulse magnetization to saturation and remagnetization by magnetic field pulses of a constant amplitude. [ABSTRACT FROM AUTHOR]

The magnetorheology of a "suspension" of millimetric-size steel spheres in oil has been studied. After a precise measurement of the magnetic properties of the particles we show that the yield stress is well characterized and that it can be predicted by a finite element method and a non-affine model where the chains break in the middle. Some experiments in microgravity confirm that the sedimentation does not alter our results and also shows that the magnetic stress decreases with the shear rate. [ABSTRACT FROM AUTHOR]

Measurements of the bulk magnetic properties for two non-oriented electrical steels after a rapid heating are reported. A deterioration of the magnetic properties was observed for the fully processed non-oriented grade and an improvement for the semi-processed non-oriented grade. This publication emphasizes the effects due to the competition between the increase of the grain size and the appearance of thermal stresses during the rapid heating on the magnetic properties of the steels. [Copyright &y& Elsevier]

Nondestructive characterization (NDC) of materials is a technology of increasing application by industrial users for process monitoring and control as well as in predictive maintenance procedures integrated in plant lifetime management systems. The main reason for this tact in materials processing is the need for a better process understanding and mastering in order to produce quality according to a zero-defect-principle and the objective to reduce non-conformities compared with a given quality specification. This means: Integration of NDC by use of intelligent sensors into monitoring and control systems to predict mechanic properties and to detect and document their discontinuities. For lifetime management of components in plants NDC is asked for to support lifetime prediction procedures, which have to be observed if lifetime extension is an objective to reduce costs. [ABSTRACT FROM AUTHOR]

Magnetic Barkhausen Noise (MBN) was used to evaluate the magnetic behaviour of nuclear reactor pressure vessel steel specimens cold rolled to reduction ratios between 0% and 60%. Measurements performed at increasing reduction ratios revealed variations in the angular dependence of a parameter termed ‘MBNenergy’, concurrent with modifications in the shape of the pulse height distribution curves. The angular preference of MBNenergy present prior to cold rolling was destroyed at intermediate reduction ratios (≈25%), and restored with further reduction (≈40%). Along the rolling direction, the number of large voltage pulses was reduced at reduction ratios of ≈25%, increasing again at ≈60% reduction ratio. Results were attributed to competing effects between crystallographic texture, microscopic and macroscopic residual stresses. [ABSTRACT FROM AUTHOR]

Focuses on a study which examined the modeling of thin steel shells placed in a static magnetic field. Behavior of the sheet; Information on global formulations; Conclusion.

Presents information on a study which focused on a two-dimensional hysteresis model constructed to represent the magnetic behavior of steel laminates. Methodology; Identification of model parameters; Conclusions.

Reports that in steel specimens subjected to grinding, it was discovered that the indications of the material changes in the surface could be determined from an analysis of the Barkhausen signal. Microstructure and residual stress changes in steel caused by grinding.

The article presents a discussion related to magnetic properties of SUS 304 austenitic stainless steel after tensile deformation at elevated temperatures. Austenitic stainless steels are widely used in a variety of hostile environments applications, such as nuclear reactors and chemical plants, where the combination of good corrosion resistance with high strength, stiffness, and toughness is required. However, one of the most widely used austenitic stainless steel SUS 304 contains metastable austenitic phase, which is easily transformed into martensitic phase due to deformation and change of temperature. With the increase of martensitic transformation, the strength of material increases, while ductility and corrosion resistance decreases.