Fig 1 - uploaded by Marie-Hélène Mathon
Content may be subject to copyright.
SEM microstructures of as-received copper (A) and drawn wire (ε2 = 71.64%) (B).
Source publication
The aim of this study is to clarify the relation between microstructure and properties (hardness and electrical resistivity) of copper wire drawing by the ENICAB Company and distended for electrical cabling. In this work we studied the evolution of the microstructure and (mechanical/electrical) properties of the wire drawn and annealed at 260 °C. T...
Contexts in source publication
Context 1
... microstructures (Fig. 1) show as-received wire form equiaxed grains. However, in the longitudinal plane of the drawn wire, there is a microstructure of elongated grains along the axis of drawing (Fig. 1b). According Zidani et al. [1,2] depending on whether the level of de- formation increases, the drawn wire acquires a textured brous microstructure. This ...
Context 2
... microstructures (Fig. 1) show as-received wire form equiaxed grains. However, in the longitudinal plane of the drawn wire, there is a microstructure of elongated grains along the axis of drawing (Fig. 1b). According Zidani et al. [1,2] depending on whether the level of de- formation increases, the drawn wire acquires a textured brous microstructure. This texture is frequently ob- served in the wires drawing and is known as the texture of ber or brous texture, because it resembles the ar- rangement of a brous material. A structural scale ...
Citations
... Here everything depends on the technology of wire making, for example, when drawing wire [24]. It is important to note that the grains elongated along the direction of wire drawing (Fig. 3, b), will be easier to undergo thermal oxidation due to their strain state [25]. That is why, in order to obtain comprehensive information about the microstructure of copper wires exposed to different temperature modes, it is necessary to examine both crosswise and lengthwise microsections. ...
... OM images of crosswise and lengthwise surfaces of the copper wire in its original state are shown in Fig. 4. It can be seen that the samples consist of polycrystalline grains elongated along a line, coinciding with the direction of wire-drawing [24,25]. It is noteworthy that in the crosswise microsection (Fig. 4, a) grains of the original copper are almost invisible, while in the lengthwise microsection ( Fig. 4, b) those are quite clearly visible. ...
The purpose of the work is to investigate the causes of vehicle ignition by analyzing the microstructure of copper conductive elements of automotive wiring. This study considers the three most likely vehicle fire scenarios. According to the first scenario, a fire occurs due to overheating of the automotive wiring by short circuit currents. In the second scenario, car fires result from direct exposure to an open flame. In the third scenario, vehicle fires are due to the combined effects of short circuits and open flames. These three scenarios affect the microstructure of copper conductive automotive wiring elements in different ways. Microstructural analysis of copper wires exposed to the temperature conditions of these three fire scenarios was carried out using an optical microscope (OM) and a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) spectrometer. It has been disclosed that when exposed to an open flame on a copper wire, the fine-grained microstructure of the original copper wire turns into a coarse-grained one. The impact of an electric arc caused by a short circuit can instantly melt copper wires. As a result, local spherical inclusions (beads and pits) appear on the surface of the copper wire, and grains of the dendritic structure are formed in its surface layer. The impact of an open flame on already short-circuited copper wires transforms their fine-grained microstructure containing local spherical inclusions into a kind of coarse-grained microstructure with clear boundaries between grains consisting of copper(II) oxide. The study of the microstructure of copper wires taken from a burned-out car should form the basis for studying the causes of car fires.
... Also there was an increase in electrical resistivity with deformation and a decrease in aging after the latter (Figure 4). and deformation conditions (temperature, speed and mode of deformation) [7]. Indeed, the cold deformation causes a substantial increase of the dislocation density (i.e. ...
The purpose of this work is to study the evolution of the microstructure, mechanical and electrical properties of an aluminum alloy, depending on the deformation level and annealing treatment. The study was conducted on an AGS type aluminum wire used by the international company ENICAB of Biskra for electrical cabling. These wires were obtained by the cold drawing process undergo annealing treatment at the temperature 170 °C for different holding times (10 minutes, 4 hours and 20 hours). Various analysis techniques were used in this study to monitor the microstructural evolution, mechanical and electrical properties. The optical and electron microscopy, micro-hardness, tensile test and electrical resistivity measurement were used. It was noted that the drawn aluminum wire causes an increase in the micro-hardness. On the other hand, the annealing at 170 °C does not cause significant changes on the evolution of the mechanical strength and electrical resistivity compared to the deformed state. Furthermore there has been a remarkable decrease in elongation after 4 hours at 170 °C annealing compared to the deformed state.
... The drawn wires are typically produced by wire drawing technique, which is one of the most frequently applied techniques in the wire manufacturing industry. This process is one of the oldest metal forming processes [8,12], During the wire drawing operation, the steel wires are cold drawn for cross-sectional reduction by passing through multiple stages of dies [9,13,14]. wire drawing improves the mechanical properties of the wires. This has been attributed on the one hand, to the development of dislocation density, the re-orientation of cementite lamellae into the drawing direction. ...
In this paper, the evolution of texture in the ferrite phase and mechanical behavior of cold-drawn pearlitic steel wires produced for strand manufacturing at Trefisoud company was investigated. Wire drawing induces the development of dislocation density, reduction of interlamellar spacing and the refinement of grains size which leads to a strong hardening of the wires. That explains the increase of the tensile strength from 1242 MPa to 2618 MPa with higher deformation. Also, the cementite lamellae are rotated toward the drawing axis and the thickness of lamellae further decreases when strain level increases, this phenomenon leads to a somewhat fibrous structure. The quantitative analysis obtained by EBSD data shows the development of a strong (<110> // ND) texture of the ferrite phase leading to a structural transformation from isotropic to anisotropic.
... This shows that there is no discontinuity or lack of penetration in the fusion zone which indeed results in no porosity and slag inclusion in the weldment which is a major inherent defect of the ETP copper (Fig. 5). This cup and cone formation indicates the ductile failure of the metal after welding, which results in decreasing the tensile strength of the weldment; this is generally due to the more heat-affected zone of the weldment [14] (Fig. 6). The microstructural photograph of the FSW weldment (weld zone, heat-affected zone) including the parent metal which is used as weldment in the process in a longitudinal direction and transverse directions. ...
The attempt of this work is to overcome the challenging tasks due to the inherent drawbacks of electrolytic tough pitch (ETP) copper while performing welding on it. It was a comparative investigation between gas tungsten arc welding (GTAW) as well as friction stir welding (FSW) on ETP copper. The specimen is an alloy of copper (degree C11000), which consists of pure copper and silver about 99.9%. ETP copper has vast applications in the industry because of good properties such as corrosion resistance, electrical, and thermal conductivity. The GTAW process is done after cold rolling of copper, and FSW has performed after nitriding the specimen. The micro and macrostructure hardness is calculated for parent material, weldment of GTAW and FSW process to compare the variation in mechanical properties of ETP Copper with the parent material. This experimental study observed that the GTAW process is feasible to achieve defect-free weldment but FSW process can be done by investing less energy, time, and resource.
... The twisting is often realized by special tools allowing to twist all ends of on layer or even all hairpin ends of the stator at once. [28] The increase in the conductor's resistance during bending can be attributed to two main factors: The first is caused by microstructure changes or lattice disturbances due to cold deformation and hardening of the surface layer [29] [30]. This effect falls behind these of cross-sectional rejuvenation and conductor extension [22] [31]. ...
To face the challenges posed by the electrification of the automotive drivetrain, rotating electrical machines are getting an impetus to innovation. Thus, machines of high power density are required to be manufactured cost-effectively in a large-scale production. To meet these requirements, the application of stators with hairpin windings is focused in industry and research institutions, as they show potentials to realize improved copper fill ratios in the armature slots. In addition, this technology also is seen as one possibility to substitute the elaborate winding technologies that often feature a lack of reproducibility, by bending, assembling and joining processes. During the design of electric drives, the influences of deviations of manufacturing processes on its performance usually are not taken into account. This particularly applies to the technology of hairpin windings, whose manufacturing requires a large number of bending and contacting operations. These process steps may influence the electrical properties of the winding, changing the behavior of the electrical machine. For this reason, the objective of this paper is to identify deviations in the manufacturing processes of hairpin windings and to validate their influence on the performance of the drive. For this purpose, measuring systems are set up which make it possible to quantify the influence of bending and contacting processes on the electrical properties of the winding by means of highly accurate resistance measurements. As next step, a simulation is set up to map the production influences on the hairpin winding to the machine’s efficiency. Based on simulation studies, the influences of the manufacturing imperfections on the engine performance become visible.
... Literature survey [1][2][3][4][5] shows that electrical characteristics of metallic solids depend on their microstructure. For instance, Zidani et al [1] measured the electrical resistivity (ρ) of 99.26 wt.% pure copper wire in drawn and annealed states. ...
... Literature survey [1][2][3][4][5] shows that electrical characteristics of metallic solids depend on their microstructure. For instance, Zidani et al [1] measured the electrical resistivity (ρ) of 99.26 wt.% pure copper wire in drawn and annealed states. The electrical resistivity of drawn wire was always higher than that in the annealed state. ...
... The results could be correlated with the electrical characteristics of metallic solids and their microstructure [36]. Metals having high density of dislocations and small vacancy clusters offer increased electrical resistivity in comparison to those with less defects and large vacancies because these structural defects act as barrier against the movement of electrons in the metal. ...
... Literature survey [1][2][3][4][5] shows that electrical characteristics of metallic solids depend on their microstructure. For instance, Zidani et al. [1] measured the electrical resistivity ( ) of 99.26 wt.% pure copper wire in drawn and annealed states. ...
... Literature survey [1][2][3][4][5] shows that electrical characteristics of metallic solids depend on their microstructure. For instance, Zidani et al. [1] measured the electrical resistivity ( ) of 99.26 wt.% pure copper wire in drawn and annealed states. The grains in the drawn state were elongated along the axis of drawing, and were equiaxed in the annealed state. ...
Six specimens of 99.995% pure zinc in the form of strips (15 mm × 8 mm × 0.5 mm) were irradiated with Q-switched pulsed Nd:YAG laser (λ = 532 nm, E = 50 mJ, τ = 6 ns, repetition rate = 10 Hz) in vacuum ∼10−3 Torr. The specimens were irradiated with 50, 60, 70, 80, 90 and 100 laser shots; the laser fluence and laser intensity at the irradiation spot were 4.24 J/cm2 and 7.07 × 108 W/cm2, respectively. Surface morphology of laser irradiated specimens was examined by both optical and scanning electron microscopes. Crater area as well as heat affected area were measured by optical microscope using Motic software. Scanning electron microscope (SEM) examination revealed different features, e.g., wavelike structures, ridges, dips, micro cones, cavities, nano and micro size droplets, as well as solid flakes, etc., on the surface. These features are a result of splashing, hydrodynamic and exfoliational sputtering. Average surface roughness was measured from SEM micrographs using Nanotec software WSxM 5.0 develop 1.1. The electrical resistivity was determined by four-point probe technique. It is observed that average surface roughness and electrical resistivity vary with the number of laser shots in an identical manner, and are therefore found to be directly related to each other.
... There was also an increase in electrical resistivity along the applied deformation " Figure 3". This type of result has already been met on wire drawn (copper/steel) [5][6][7]. ...
In this study, we tried to understand the texture evolution of deformation during the cold drawing of copper wire (99.26%) Drawn by the company ENICAB destined for electrical cabling and understand its link with the electrical conductivity. Characterisations performed show the appearance and texture development during the reduction of section of the wire. The texture is mainly composed of the fiber < 111 > // DN (DN // drawing axis) (majority) and the fiber < 001 > // ND (minority) whose acuity increases with deformation level. The wire was performed for the main components of the texture, ie the fiber < 100 > and < 111 > conventionally present in these materials. We will pay particular attention on the energy of the cube component {100}< 001 > recrystallization that develops when the level of reduction is sufficient. There was also an increase in hardness and electrical resistivity along the applied deformation.
