Wire Surface Research Articles

Fretting Behaviors of Steel Wires with Tensile-Torsional Coupling Force Under Different Wire Diameters and Crossing Angles

Fretting wear among steel wires is one of the important factors for the wire rope fracture. The influence of the wire diameter and crossing angle on the fretting fatigue behaviors of steel wires under tensile-torsional coupling force was explored in the present study. The test principles and analysis methods were introduced. Result shows that the variation laws of the coefficient of friction (CoF) between steel wires with increasing crossing angle under different wire diameter contacts are the same. For the same crossing angle, the CoF under different test conditions increases in the following sequence: both with the diameter of 0.8 mm < both with different diameters < both with the diameter of 1.0 mm. According to the hysteresis loops of the frictional force versus displacement amplitude, the contact area between steel wires with larger crossing angle is easier to enter into partial slip state. Moreover, as the crossing angle increases, the relative amount between steel wires increases in the relatively stable phase, and the wear is more drastic. The main wear mechanisms of steel wires with different wire diameters are fatigue wear and adhesive wear, and the worn surface of steel wires shows more obvious abrasive wear with decreasing crossing angle.

Abnormal grain growth in thin wires of commercially pure iron with anisotropic microstructure

This work reports the behavior of annealed commercially pure cold-drawn thin iron wires. Primary recrystallization is complete after holding for 180 s at 1123 K. After recrystallization, grain growth takes place within the central region but not close to the surface. For annealing times up to 14400 s, the grain size distribution broadens and the texture strengthens. The resulting texture is intense along the direction <110> parallel to the wiredrawing direction (WD). For longer times, abnormal grain growth takes place. The center of the wire is the preferred place for abnormal grain growth. By contrast, the grains closer to the surface do not experience any growth, and abnormal grains cannot consume them. Throughout the microstructure, one finds AlN and MnS particles. Close to the wire surface, there is a significantly higher particle density than in the center. We discuss mechanisms for the onset of abnormal grain growth, considering particle pinning and crystallographic texture. We observed two kinds of abnormal grains. Most abnormal grains belonged to the <110 > // WD fiber texture component, whereas a minority did not. We propose two mechanisms of abnormal grain growth initiation. The first mechanism explains the initiation of the abnormal grains with the assistance of the texture. The second mechanism associates the formation of a candidate abnormal grain to the topological path of the largest grains during normal grain growth preceding the onset of abnormal grain growth.

Environmental fatigue of superelastic NiTi wire with two surface finishes

Surface finish of NiTi is widely perceived to affect its biocompatibility and corrosion fatigue performance. The aim of this work was to find out, whether a carefully engineered surface oxide shows any beneficial effect over electropolished surface on the fatigue performance of superelastic NiTi wire mechanically cycled in simulated biofluid. Series of corrosion and environmental fatigue tensile tests was performed on superelastic NiTi wire with two different surface finishes frequently used in medical device industry. Open Circuit Potential reflecting the activity of chemical reactions on the surface of the wire cycled in electrochemical cell was continuously monitored during the fatigue tests. Microcracks at the surface of the fatigued NiTi wires were characterized by SEM and TEM. It was found that the carefully engineered 70 nm thick TiO2 oxide provides the NiTi wire with similar level of protection against the static corrosion as the less than 10 nm thin natural oxide on the electropolished wire and that it does not have any positive effect on its performance in environmental fatigue tests, whatsoever. On the contrary, the wire covered by the carefully engineered 70 nm thick TiO2 oxide displayed systematically poorer fatigue performance upon tensile cycling under specific critical loading conditions (strain amplitude <0.5% at large mean strains 1–7%).

Effect of Wire Pitch on Capacity of Single Staggered Wire and Tube Heat Exchanger Using Computational Fluid Dynamic Simulation

Single staggered is a design development of normal wire and tube heat exchanger that wires are welded with staggered configuration on two sides. Capacity of wire and tube heat exchanger is the ability of the heat exchanger to release heat. The objective of this study is to analyse the effect of wire pitch (pw) on capacity of single staggered wire and tube heat exchanger. The research method uses Computational Fluid Dynamic (CFD) simulation by ANSYS Fluent to analyse heat transfer of wire and tube; also to analyse airflow at surface the wire and tube. The simulation is experimentally validated by measuring temperatures at some points of wire and tube. Based on results, temperature contours increasing capacity of heat exchanger depend on smaller wire pitch that the highest value is 72.02 W at pw 7 mm. The reason is smaller wire pitch increases area of convection heat transfer surface. Whereas, airflow patterns show air move slowly at the wire and tube surface and flow with free convection. This study contributes new design of wire and tube heat exchanger with CFD and it can be applied to improve the performance of this heat exchanger in refrigeration system and other applications.

Analysis of the Interstrand and Strand/Connector Resistance Relations in Wire Connection Systems

The basic function of wire connection systems is to assure a low resistance and a stable long-term electromechanical connection. The quality of this connection is determined by the quality of a large number of electromechanical interstrand and strand/connector contacts. The aim of this study is to analyze the parameters that influence the performance of wire connection systems with a new measurement method. A detailed analysis enables a deeper understanding and provides extended information about the inner electromechanical connection behavior. This analysis method can be used both for the fundamental research and the optimization of wire connection systems design. Hexagonal crimp connections with different wire surface conditions were analyzed. Furthermore, a numerical calculation method is introduced to describe the performance of wire connection systems in order to gain a deeper understanding of the results.

Study of the physicochemical and biological properties of the new promising Ti–20Nb–13Ta–5Zr alloy for biomedical applications

A technology for producing a new homogeneous Ti–20Nb–13Ta–5Zr alloy has been developed. It is shown that the alloy is single-phase with a β-Ti type crystal lattice. The alloy has the required mechanical properties (tensile strength of about 745 MPa). On the surface of plates and wire made of alloy, a relief of micro- and nanoscale is observed. In terms of the ability to generate reactive oxygen species and long-lived reactive protein species, the Ti–20Nb–13Ta–5Zr alloy is more preferable than nitinol. It was established that cell cultures growing on plates or wire made of Ti–20Nb–13Ta–5Zr alloy had a significant mitotic index (2%). The number of viable cells was at least 95–96% of the overall cell count. According to the results of implantation of the alloy in the form of plates or wire ring to animals, it can be concluded that the alloy is biocompatible. The morphology of the surface of the samples did not change after biological experiments. It can be assumed that the alloy Ti–20Nb–13Ta–5Zr is a material potentially suitable for medical applications.

The development of a micro-coil-on-ASIC type GSR sensor driven by GHz pulse current

Through applying GHz (Gigahertz) pulse current on the amorphous micro wire, we observed an increase in the coil voltage around the wire, and a sine function relationship between the coil voltage and the surrounding magnetic field. We assumed that the new performance of the coil voltage must be caused by the rotation of electron spins on the wire surface with GHz angular velocity, induced by the magnetic field force in the same direction, and proposed to name the observed new phenomena as GSR (Gigahertz Spin Rotation) effect. The developed GSR sensor presents excellent features with enhanced sensitivity and low hysteresis better than that of the GMI (Giant Magnetoimpedance) sensor.We developed the production technology to produce micro coils and developed a Micro-coil-on-ASIC (Application Specified Integrated Circuit) type GSR sensor, where the micro coils are directly formed on the ASIC surface, making small size GSR sensor possible.

Headspace solid-phase microextraction sampling of endogenous aldehydes in biological fluids using a magnetic metal-organic framework/polyaniline nanocomposite.

Nanoporosity, crystal structure, good thermal and mechanical stability, high surface-to-volume ratio, nanoscale cavities, and uniform pore topology have made metal-organic frameworks one of the best class of sorbents for adsorption/separation purposes. In this research, a metal-organic framework/polyaniline magnetite nanocomposite was synthesized and intercalated by polyaniline by electrophoretic deposition on the surface of a thin steel wire, to prepare a solid-phase microextraction fiber. It was coupled with gas chromatography-flame ionization detection and employed for the extraction and determination of aldehydes in biological samples. The magnetic nanocomposite was characterized using scanning electron microscopy, energy dispersive X-ray analysis, and Fourier transform infrared spectroscopy. Under the optimal experimental conditions, the calibration curves were linear in the range of 0.01-1 and 0.1-1µg/L for hexanal and heptanal, respectively. The limits of detections for hexanal and heptanal were 0.001 and 0.01µg/L, respectively. Intrafiber repeatability for six replicate analyses of 0.2µg/L of the analytes was over the range 3.5-7.1%. Interfiber (fiber-to-fiber) reproducibility, calculated by six replicate analyses of the same concentration using three different fibers, and was found to be 10.4-15.7%. The developed procedure was successfully utilized for the analysis of hexanal and heptanal in human plasma and urine samples.

Study on corrosion fracture diagnosis method of grounding wire of tower grounding device

Tower grounding device provides the discharging channel for currents under lightning and fault. However, the grounding wire is prone to corrosion. Existing detection methods through measuring the grounding resistance to detect fracture, but it suffers from poor accuracy when the fracture grounding wire is inconsistent with the detection position. This paper proposed a simple, rapid and effective diagnosis method based on the ground potential rise (GPR). Firstly, the non-uniform corrosion characteristics of the grounding wire in soil are analysed and the corrosion deformation regularity of the grounding wire surface is obtained. Then the fracture model of the grounding wire is developed. The GPR variation feature and mechanism of the grounding wire under faults are studied. Finally, the simulation and experimental results show that the proposed method can accurately detect the fracture status of the tower grounding wire, which can provide a solid basis for diagnosis of the tower grounding devices.

Effect of ambient pressure on the extinction limit for opposed flame spread over an electrical wire in microgravity

Parabolic flight experiments were carried out to investigate the effect of ambient pressure on the extinction limit for opposed flame spread over an electric wire insulation in microgravity. Low-density polyethylene insulated Nickel-Chrome wires with inner core diameter of 0.50 mm and insulation thickness of 0.30 mm were examined for ambient pressures ranging from 50 kPa to 140 kPa for an external opposed flow of 10 cm/s. The experiments showed that the limiting volumetric oxygen concentration (LOC) increased as the total ambient pressure decreased. This LOC trend can be explained by radiation loss from wire surface. The radiation loss increased as the ambient pressure decreased – a result that can be explained by the increase in preheat length with decreasing ambient pressure. Moreover, when the data was plotted in a partial pressure vs. total pressure space, it became evident that the limiting oxygen partial pressure (LOPP) decreased with decreasing total ambient pressure. This LOPP trend can be explained by the fact that the flame temperature increased as the ambient pressure decreased under constant oxygen partial pressure. In current fire safety design for spacecraft, tentative oxygen concentration criteria in spacecraft suggested by NASA is assumed as 30% of oxygen concentration, and this value is assumed independent of ambient pressure. However, the present result implies that consideration of the effect of ambient pressure on the flammability limit is necessary, especially with respect to the possibility of an extension of the allowable atmosphere condition for spacecraft cabin in the low pressure region.

Effect of phonon-boundary scattering on phonon-drag factor in Seebeck coefficient of Si wire

For highly efficient thermoelectric devices with Si nanostructures, we have fabricated and characterized micro/nanometer-scaled Si wires preserving the phonon-drag effect in order to observe the impact of phonon-boundary scattering on the phonon-drag factor in its Seebeck coefficient. The observed phonon-drag factor in the Seebeck coefficient decreases with a decrease in the wire width, which is considered due to an increase in the boundary scattering of phonons. Since the boundary scattering is characterized by the specularity parameter, we measured the surface roughness of the wire and evaluated the specularity. It was found that the top surface of the Si wire has higher specularity compared with the sidewall of the wire in the range of phonon wavelength contributing to the phonon drag. This result qualitatively explains the fact that the phonon drag in the Seebeck coefficient is hardly affected by the wire thickness with a nanometer order, whereas the wire width influences it significantly even on a micrometer scale. Moreover, it is demonstrated that the phonon-drag effect in the Seebeck coefficient of Si nanostructures can be preserved while their thermal conductivity is lowered.

Steel Wire Cleaning using Cold Plasma

Current galvanizing process used hydrochloric acid to remove oxide layer and mild acidic bath to remove oil on metal wire surface. These cleaning processes are compulsory before steel wire coated with zinc. These chemicals cleaning technique cause ecological harm and produce toxic waste. To consider of minimizing these problems, cold plasma was introduced for metal wire cleaning. Previous research already proves that cold plasma capable to remove oil by using dielectric barrier discharge (DBD) and remove oxide layer on copper by using RF plasma discharge. Therefore, in this research, the same plasma discharge system that is DBD was used to remove oil and oxide layer on steel wire. 8kV of voltage and air was used to generate plasma. By using copper and steel wire as electrode, it can remove oil around 82% and oxide layer around 54%.

Experimental investigation of transient pool boiling characteristics of [formula omitted] ferrofluid in comparison with deionized water

Pool boiling heat transfer and critical heat flux (CHF) in ferrofluid were experimentally studied under transient power conditions. The heat flux increment was begun from the free convection regime to the film boiling regime. Transient boiling heat transfer coefficient (TBHTC), transient CHF, scanning electronic microscopy (SEM) images of surface wire, and high-speed camera images were obtained. The following results were obtained for ferrofluid: as the time period increased, (1) the heat transfer coefficient of the nucleate boiling increased because of bubble production and its movement, then decreased in the transition from the nucleate to the film boiling because of an unstable layer of vapor around the wire heater and finally increased again in the film boiling because of the high temperature of the wire surface and radiation heat transfer; (2) the CHF and its wire superheat temperatures at CHF point decreased by up to a period of 100 s; (3) the incipient boiling point decreased. In the second part of the film boiling, the heat transfer coefficient was decreased because of the high heat flux and the more vapor film thickness around the wire. A comparison between two working fluids show that by increasing the time period, the nucleate boiling range of ferrofluid boiling was increased more than the deionized (DI) water boiling. Furthermore, the wire superheat temperature of the ferrofluid in all its regimes was decreased and the CHF of ferrofluid boiling were increased more than the DI water boiling. The ferrofluid CHF at the time period of 1 s decreased by 11.3% relative to DI water, and at the time period 5000 s increased by 160%.

Study on fracture of tungsten wire induced by acoustic cavitation at different hydrostatic pressures and driving electric powers.

The near-solid wall multi-bubble cavitation is an extremely complex phenomenon, and cavitation has strong erosiveness. The melting point (about 3410°C) of tungsten is highest among all pure metals, and its hardness is also very high (its yield strength is greater than 1 GPa). What would happen to pure tungsten wire under extreme conditions caused by collapsing cavitation bubbles at high hydrostatic pressure? In this paper, we have studied the fracture process of pure tungsten wire with diameter of 0.2mm mounted at the focus of a standing acoustic wave produced by a spherical cavity transducer with two open ends placed in a near spherical pressure container, and also studied the macro and micro morphological characteristics of the fracture and the surface damage at different fracture stages of tungsten wire under various hydrostatic pressures and driving electric powers. The results have shown that the fracture time of tungsten wire is inversely proportional to avitation intensity with hydrostatic pressure and driving electric power, the higher the acoustic pressure caused by higher electric power, the shorter the fracture time. The possible fracture mechanisms of tungsten wire in this situation we found mainly contributed to asymmetrically bubbles collapse near the surface of tungsten wire, leading to tearing the surface apart; consequently cracks along the radial and axial directions of a tungsten wire extend simultaneously, classified as trans-granular fracture and inter-granular fracture, respectively. With the increase of cavitation intensity, the cracks tend to extend more radially and the axial crack propagation path becomes shorter, that is, mainly for trans-granular fracture; with the decrease of cavitation intensity, intergranular fracture becomes more obvious. When the hydrostatic pressure was 10MPa and the driving electric power was 2kW, the fibers became softener due to the fracture of the tungsten wire. The fracture caused by acoustic cavitation was different from conventional mechanical fracture, such as tensile, shear, fatigue fracture, on macro and micro morphology.

Experimental Study on Fatigue Crack Propagation of High-Strength Steel Wire with Initial Defects for Bridge Cables

In order to study the effect of initial defects on fatigue crack propagation law, a test method to identify fatigue crack propagation rate and path based on load waveform variation was presented, and a new test device was designed to apply fatigue pulsation loads to multiple wires for bridge cables simultaneously in this paper. To simplify the corrosion defect formation process, a machine-cut notch was used to describe the initial defect on the steel wire surface. Firstly, fatigue crack propagation tests were conducted on the surface notched steel wire specimens. By using crack front marking technique, the “beach-like patterns” visible to the naked eyes on the cross sections of the steel wires were formed, and the process of fatigue crack propagation can be tracked and reproduced. Then Autodesk Computer Aided Design (AutoCAD) software was used to describe the morphology of “beach-like patterns” and accurately measure the depth and width of cracks. Finally, the influence of initial defect morphology on fatigue crack propagation rate was investigated according to the relationship between fatigue cracks depth and cyclic loading numbers. The results show that the test device designed in this paper can effectively realize the synchronous fatigue crack propagation test of multiple wires, and significantly shorten the fatigue test period. By observing and analyzing the change of load waveform, the moment of fatigue crack propagation can be directly and accurately determined. The larger the depth, the smaller the width and the sharper the morphology of initial defect, the faster the crack propagation rate and the shorter the life of notched wire specimens under the combined action of fatigue loads and corrosive medium.

Formation mechanism of wire bow and its influence on diamond wire saw process and wire cutting capability

Wire bow is the most important factor affecting wire sawing capability of silicon ingots. In this paper, the wire bow, contact length in cutting zone which reflects the DWS process are emphasized. The real-time signals of wire bow are analyzed after a series of cutting tests. The relationship between cutting power and MRR was built for identifying the cutting condition of diamond wire. And it was found the cutting capability of diamond wire was losing with the wire feed into the ingots which is accompanied by the increase of wire bow. The silicon wafer surface was observed by SEM and 3D profiler to analyze the geometric characteristics of wire bow, wire mark morphology and surface topography. This research is used to master the formation mechanism of wire bow and its influencing factors in order to control the loss of wire cutting capability.

Cylindrical micro and nanowires: Fabrication, properties and applications

The state of the art in cylindrical nano and micro wires is reviewed with particular emphasis on the latest research trends. We analyze some of the key properties for prospective applications including magnetic anisotropy and micromagnetic structure, spin-caloritronics, domain wall dynamics and its control by transverse magnetic field and induced anisotropy, high frequency impedance and magnetic control of the electric polarizability, shape-memory and magnetocaloric effects in Heusler alloys wires. Cylindrical nanowires present specific magnetic domain configurations as complex vortex and transverse domains while the magnetization reversal typically involves propagation of Bloch-point domain walls. Such magnetic behavior offers new perspectives for applications in advanced technologies including spintronics, logic devices and novel magnetic recording media, functionalization and bioengineering and sensor devises. In particular, rapidly solidified glass-coated amorphous nanowires and submicron wires which constitute a novel class of ultrathin soft magnetic materials are attractive for future micro and nano sensors.Amorphous and nanocrystalline microwires prepared by rapid quenching from the melt can present quite peculiar magnetic properties, like spontaneous magnetic bistability associated with single and large Barkhausen jump and magnetoimpedance effect. Magnetic properties of amorphous microwires are related to the value and sign of the magnetostriction constant since the magnetoelastic anisotropy is one of the main sources of the magnetic anisotropy. As-prepared microwires with positive magnetostriction constant show generally rectangular hysteresis loops and fast domain wall propagation. In the case of low and negative magnetostriction, the wires demonstrate inclined hysteresis loops and large magnetoimpedance. To refine the magnetic structure, the easy anisotropy can be adjusted by annealing in the presence of a magnetic field and/or mechanical stress. Thus, the magnetic bistability in negative magnetostriction wires can be induced by annealing. Minimizing the magnetoelastic anisotropy either by adjusting the chemical composition with a low magnetostriction coefficient or by heat treatment is an appropriate route for enhancing the domain wall velocity. Tailoring the magnetic anisotropy by stress-annealing is also a promising method of the optimization of the domain wall dynamics in magnetic microwires.Soft magnetic properties and tunable magnetic structure of amorphous microwires are responsible for the magnetoimpedance effect, which preserves a high sensitivity up to GHz frequencies. This opens up novel applications based on the electric polarization of a finite-length microwire depending on the wire surface impedance near the antenna resonance, including embedded wireless sensing elements, self-sensing composites and selective microwave materials.Heusler alloys demonstrate the huge variety of physical properties that can be obtained by simple change in composition. Naturally, the efforts have been made to produce Heusler-based nano and micro wires to take advantage of variety of their physical properties in a miniature form. In this review, the emphasis is made on Heusler alloy glass-coated microwires.

Casting of Thin Bare Wire Using Wheel Caster Equipped with Rotating Side-Dam Plates

A simple twin-wheel caster is proposed for casting thin bare wire. An unequal diameter twin wheel caster equipped with rotating side-dam plates is proposed for casting a thin bare wire of aluminum alloy to shorten the fabrication process. The rotating side-dam plate was made of mild steel. Al-10%Mg bare wire with a rectangular cross section could be cast at wheel speeds of 3 and 4 m/min. Area of the bare wire was less than 100 mm2 at these wheel speeds. The side surface of the bare wire was made flat by the rotating side-dam plates. The rotating side-dam plates prevent the cross section of the bare wire from becoming concave.

“AN EFFECT OF TWO COMMERCIALLY AVAILABLEDENTRIFICES ON NICKEL-TITANIUM AND STAINLESS STEEL ORTHODONTIC ARCHWIRES: AN IN-VITRO STUDY”

Aim The study aimed to evaluate the effect of two commercially available dentifrices on Nickel-Titanium and Stainless Steel orthodontic arch wires. Methods A total of 33 rectangular NiTi (0.019” x 0.025”) and 33 rectangular Stainless Steel (0.019” x 0.025”) wires were taken for this study. Each group containing 16 wires were treated with the following dentifrices; Group A - Colgate Strong Teeth Toothpaste Group B – PatanjaliDantKanti Toothpaste when mounted on typhodont with help of power toothbrush. the sample were scanned under Stereo Microscope at 35x magnification and Scanning Electron Microscope at 500x magnification to check whether the dentifrices have deleterious effects on the orthodontic arch wires. The recorded data was tabulated in MS-Excel and analyzed using one-way ANOVA. Statistical analysis was performed using SPSS statistical software at the 0.05 significance level. Descriptive statistics were done using the paired t- test for the intra group comparison and unpaired t- test for the inter group comparison. Results The SEM surface analysis revealed that the most surface variations were seen with the Stainless Steel arch wires treated with the Group A toothpaste followed by the Stainless steel wires treated with the Group B toothpaste. Both the groups demonstrated depressions, pores, furrows or grains in 1/3rd of the surface of the arch wire. However, the dimensions of the depressions, pores furrows was greater in the wires treated with Group A toothpaste when compared to the Group B toothpaste. Also, with the NiTiarchwires treated with the Group A toothpaste showed more surface variation compared to the NiTi wires treated with the Group B toothpaste. Both the groups demonstrated depressions, pores, furrows or grains in 1/3rd of the surface of the archwire. However, the dimension of the depressions, pores, furrows was greater in the wires treated with Group A toothpaste when compared to then Group B toothpaste. Conclusion The stainless steel archwires exhibited the maximum alterations in surface topography after treatment with both the dentifrices when compared to the Nickel-Titanium wires.

Improvement of saw damage removal to fabricate uniform black silicon nanostructure on large-area multi-crystalline silicon wafers

The first step of preparing black silicon solar cells by Ag metal-assisted chemical etching method (Ag-MACE) is to remove the saw damage layer on the surface of diamond wire saw multi-crystalline silicon wafers. The usual way to do this is with a hot solution of KOH. However, the surface of silicon wafers processed in large quantities in this way will have many white spots and stains. These white spots and stains are the saw damage layer that have not been removed cleanly. They affect not only the appearance of the solar cells, but, most importantly, the subsequent uniform deposition of silver nanoparticles on the silicon wafers. An additive containing cyclodextrin and lignosulfonate has been developed in this work. This can remove effectively the saw damage layer and eliminate the white spots and stains on the surface of the silicon wafer. So as to improve the appearance of silicon wafer and make silver nanoparticles uniformly deposited on the surface of the whole silicon wafer. This additive has been proved to be very useful in improving solar cell efficiency, raising parallel resistance and reducing reverse leakage current and so on. Eventually, mass-produced solar cells made by Ag-MACE with this additive have a maximum efficiency of 19.49%, which is 0.46 percent absolutely higher than that without the additive.