Search

Increase the hardness, the endurance and the life time of material can be realised by surface treatments and remetallings, the electromagnetic properties of steels depend on their composition, their microstructures and constraints applied. We can use the electric and magnetic parameters to evaluate their microstructure. The object of this work is the characterization of cementation by the non-destructive methods and the determination of physicochemical parameters. Samples of low carbon tenor steel were cemented with different alternatives. We studied these samples by eddy current method. The treatment of these results will be able to inform us about the cementation parameters. This work allow to determine the surface layers by NDT methods. Key words: NDT, cementation, carbon, eddy current, Micro hardness, INTRODUCTION The use properties of the metallic materials are slightly linked to their micro structural status. The characterisation of this microstructure a significant assets to the industrial, who wants to [...]

The study describes a new technique for measuring the spatial periodic bending and critical current of various bronze [Nb.sub.3]Sn strands that are tightly packed in a steel tube. The cable in conduit conductor (CCIC) does not exhibit extra degradation due to the change in matrix transverse resistivity of the material.

A time-stepping method based on the concept of magnetic viscosity developed to reproduce the excess loss in electrical steel is proposed. A numerical scheme for simultaneous solution of Maxwell equations and equations describing the magnetic viscosity has been developed. The method is suitable for describing arbitrary magnetization regimes such as waveforms associated with pulsewidth modulation (PWM) voltage excitation, and the model differential equations can be conveniently combined with equations of an external electric circuit. The accuracy of the proposed dynamic model is shown using three nonoriented electrical steel as examples. Fitting of the magnetic viscosity parameters for one sinusoidal flux regime enables dynamic hysteresis loops and losses to be predicted with high accuracy over a wide range of frequencies and amplitudes of sinusoidal or nonsinusoidal flux densities. Index Terms--Finite-difference time-domain analysis, magnetic hysteresis, magnetic losses, soft magnetic materials.

Literature data for the electrical resistivity of austenitic and ferritic steels are analyzed in a model that takes into account their composition and microstructure. The contribution of the solute elements Si, Mn, Cu, Ni, Mo and Cr were determined for ferrite, with the contribution decreasing in this order.

Optimal operating conditions for magnetic flux leakage inspection of moving steel sheets are predicted by using a 2-D finite element model and a time step algorithm. Through numerical modeling of motional induction phenomena, sensor signal variations due to different velocities are investigated. Results show that changes in specimen velocity affect the base signal level and the peak to peak (P-P) signal, but their variations are not proportional to the velocity. Also found is that the sensor position where the maximum P-P signal appears changes its location to the direction of specimen motion as the velocity increases. These results made it possible to decide optimal operating conditions, such as the velocity of steel sheet and the sensor location, to obtain the maximum signal to noise ratio.

The active electric armor will play an important role in the future of armored vehicle protective systems. The active electric armor interceptor based on the principle of a single-stage coil launcher must use nonmagnetoconductive material, such as aluminum as its inductive coil. However, in order to enhance the interception effectiveness, people hope to use high-strength magnetoconductive material, such as steel. So, the best possible way is to synthesize the two kinds of materials in actual applications. In this paper, the electromagnetic field characteristics and the force acting on the interceptor are described. The analysis of the 3-D eddy current field shows that the thrust force not only did not decrease, but it increased a little when the high-strength magnetoconductive was added. The results of the experiments verified the correctness of the simulation analysis. Index Terms--Active electric armor, electromagnetic launch, finite-element analysis.

Several studies are conducted to explain the various effects of the precipitates on the production and the magnetic domain behavior of the grain-oriented electrical steels. The presence of precipitates is shown to significantly obstruct the domain wall motion during the magnetization process.

A two-dimensional time-resolved x-ray diffraction (2DTRXRD) system for real welding was used to observe rapid solidification of weld metal. A mistlike patten which differed from the halo pattern, in the fusion zone offered insight for the possibilities to observe the nucleation and the early solidification by 2DTRXRD.

The impact of the mechanical strain on the electrical characteristics and mechanical limitation of the polycrystalline silicon thin film transistors is discussed. The results prove that the electron mobility in the system increases with the tensile stress and decreases under the compressive stress.

The effects of varying shot peening parameters on drag force signatures are investigated. The utility of the drag force method for automatic assessment of peening quality and uniformity is discussed.

A laminated-type magnetic wood using ferrite powder and stainless steel powder has served as a wood building material of suitable quality for an indoor electromagnetic wave absorber. The results for the gigahertz frequency band has shown that the laminated-type magnetic wood has an electromagnetic wave absorption characteristic and is used for preventing radio interference for indoor wireless LANs.

S parameters are obtained by using the three-dimensional (3D) finite element HFSS code in order to analyze suspension interconnects. The impedance from the 3D simulation is lower that the predicted value from the 2D simulation and it is shown that attenuation poles are present at certain frequency ranges as in band-stop filters when the window pitch or window length is large.

The variations in the longitudinal drag force on a magnet close to a slowly moving strip sample of electrical steel have provided sensitive, nondestructive indications of local inhomogeneity in the permeability, dimensions and hysteresis loss of the sample. The measurements of both grain-oriented and nonoriented electrical steels have shown drag force variations of unexpectedly large amplitude for movements of just a few millimeters.

The exchange bias behavior can be observed between strain-induced ferromagnetic (FM) [alpha]' martensite and antiferromagnetic (AFM) austenitic phase in SUS 316LN stainless steel. The decreasing exchange bias field with FM is attributed to the increasing size of FM crystallites in the AFM matrix.

A method is presented to calculate the deformation of electrical steel due to magnetic forces and magnetostriction by using the finite element method. The magnetostrictive properties of the steel are determined experimentally in a small single-sheet tester with strain gauges fitted on the sheet.

Power loss of nonoriented electrical steel was measured under sinusoidal and square wave excitation. The results show that total power loss under sinusoidal excitation is higher than that under square wave excitation. The total loss difference at the same peak flux density ranges from 7% to 15%. The dynamic losses depend on the shape of the flux waveform, its peak value and frequency. The loss under square wave excitation is less than under sine wave excitation because the mean value of dB/dt throughout the magnetizing cycle is lower provided that the peak values of the flux density waveforms are identical. An attempt is made to relate the differences to effects of distortion on individual component of loss. Index Terms--Eddy currents, losses, loss measurement, magnetic losses.

Search coils and needle probes are existing experimental sensors that can measure flux distributions in electrical steels. This work investigates and evaluates the limitations of each method, proposes the use of a new modified needle probe method and gives reasons for its improved applicability and relative merits. Index Terms--Electrical steels, flux density measurements, needle probe method, search coil method.

Continuous efforts are directed at developing improved electrical steels with lower iron losses for energy-efficient transformers and motors. The core losses can be limited by insulating coatings, and various types of coatings have been developed for application to both fully processed and semiprocessed electrical steels. The primary and secondary properties of such coatings and the inefficacy in ultimately improving machine performance are discussed. This insight is vital to design engineers in making the correct decision on coating requirements. The latest advances made in electrical steel coating technology at European Electrical Steels (EES) are also discussed. Index Terms--Coatings, electrical machines, electrical steels, energy efficiency, surface insulation.