Search

Abstract: Quantitative and qualitative analysis techniques were employed to study the first stages of ultra-high vacuum plasma nitriding of the 42CrMo4 steel. At constant treatment temperature, maintained for all samples at about 360°C, we have established the influence of treatment time on the chemical composition, thickness and electrical properties of the nitrided layer. In this purpose it was used a stacking atomic layer model describing the sample surface, which takes into account the attenuation depth of photoelectrons by the atomic monolayers. So, we have found that after 2h of nitriding in laboratory conditions, 70% of the nitrided layer was composed of iron oxide. Also, I–V measurements indicate an influence of the nitride overlayer with increasing treatment time. [Copyright &y& Elsevier]

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]

The article presents a research paper which investigates the heating properties of metallic textile structures. It applies single and multi-ply steel fabrics to electrical current to examine their heating behaviors. It places steel yarns in the fabric construction for their flexible properties, while the heating panels are made from conventional textile processes. Results suggest that the characterization of the electrical properties of conductive materials should be evaluated and the materials that have the best electrical resistance properties should be applied.

The article offers information on the effect of embedded steel on electrical resistivity of concrete structures. It is mentioned that the electrical resistivity of the concrete is an important factor in determining the rate of corrosion. A test was conducted to determine the impact of embedded steel on electrical resistivity on concrete structures. The test was conducted in relation to four electrode testing of the electrical resistivity. Details related to the effects of cover thickness and curing conditions on the resistivity were also examined.

Abstract: Steels with high amounts of silicon are used in electrical applications due to their low magnetostriction, high electrical resistivity and reduced energy losses, but they exhibit poor formability. The slow positron beam of Gent is used to investigate defects in different deformed FeSi alloys. It was found that the concentration of defects for the alloys deformed at high temperatures are different from the ones related to the alloys deformed at room temperature. These results are correlated to the results of positron annihilation lifetime spectroscopy (PALS). [Copyright &y& Elsevier]

The influence of plastic deformation on the elastic properties that determine the magnitude of springback following forming was investigated using dynamic modulus analysis. For this study, the elastic modulus of TRIP 700 steel was measured continuously at 35 °C and a loading frequency of 1.0 Hz for 1000 min following deformation by cold rolling to varying levels up to 27%. The elastic modulus increased at an exponentially decaying rate during these experiments and with a magnitude that increased with pre-strain. These observations are consistent with the hypothesis that deformation creates microstructural defects that contribute compliance when the stress state changes and that these defects are removed by annealing at this low temperature. [ABSTRACT FROM AUTHOR]

We report on the generation of radially and azimuthally polarized Q-switched laser radiation and its application in material processing. The power levels were sufficiently high to study micro-hole drilling in different metals. Depending on the optical properties of the metal, either radial or azimuthal polarization shows the best efficiency and the effect is attributed to waveguiding. For steel, a comparison to linearly or circularly polarized laser radiation indicates that the doughnut-shaped beam with azimuthal polarization is the most energy-efficient in producing holes of the same diameter and depth. [ABSTRACT FROM AUTHOR]

Presents a study which examined the electric properties of laminates made from a fabric with PP/stainless steel commingled yarn. Methods; Results; Conclusion.

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]

A non-destructive system using a Hall effect I.C. sensor has been used to measure the distribution of the vertical component of stray magnetic field on the opposite surfaces of a magnetised specimen of high permeability, grain-oriented electrical steel. An optical microscope was used to establish positions of grain boundaries in order to explain differences in field profiles outside the systematic accuracy of measurements. It was found that unlike previously assumed, grain boundaries may not necessarily be perpendicular to the sheet surface so different field distribution may occur. This should be considered when evaluating local power loss from surface sensor movements. Future studies are also necessary to quantify the effect of this phenomenon in the interpretation of surface or bulk properties of electrical steels using surface field sensors. [ABSTRACT FROM AUTHOR]

It has been confirmed that a thin steel plate can be levitated by controlling the current of electromagnets. However, the plate gets out of position in the case of high-speed conveyance of the steel plate if there is no force for restraining the plate from slipping horizontally. Then, electromagnets for controlling the horizontal position are installed. In this paper, we study how the elastic vibration of the steel plate is affected by the magnetic field produced by the electromagnets. The magnetic force pulls back the steel plate to its center. With the magnetic field produced by the electromagnets, the frequency of the vibration increases and the vibration is attenuated more rapidly. In addition, the tensile force makes the steel plate flat. [ABSTRACT FROM AUTHOR]

The effects of pulse-on duration and finishing operation on the surface roughness and electrical resistivity of AISI D2 tool steel machined by the electrical discharge machining process are investigated. Experimental results indicate that surface roughness increased depending on the pulse-on duration. However, after the specific value, surface roughness is decreased. It can be seen that there are no notable effects of the pulse-on duration on the electrical resistivity, but the resistivity values are affected by the heat treatment and the finishing operation. Also, light microscopy and scanning electron microscopy have been used to study the characteristics of the surfaces. [ABSTRACT FROM AUTHOR]