EXPERIMENTAL AND THEORETICAL INVESTIGATION OF TENSILE STRESS DISTRIBUTION DURING ALUMINIUM WIRE DRAWING

Wire drawing, has received a wide range of applications in the production. A wide number of cable applications demand that the cable survive high tensile loading. This works entails experimental and theoretical investigation of tensile stress distribution during aluminium wire drawing. The initial Aluminium rod used in this work was, 9.50mm with density of 2700kg/m3 , young’s modulus of (7x1010 Pa), Poisson’s ratio (0.33), Yield stress in simple tension (21.7 × 106Pa), which was later drawn to different diameter as required and tensile testing was carried out on each required diameter. In this work, tensile stress distribution in the drawing process is determined via experimental and analytical method. A free body equilibrium method is used to obtain the equations that dictate the drawing phenomenon. The result obtained by experiment is compared with improved model and also with other solutions found in the literature about these themes, particularly, with Rogas solutions in slab method case. There is high degree of similarity between the result obtained experimentally and the simulation of improved model but there is a wide gap when compared experimental result with simulation of classical slab method. Thus, the result of the study will be of great benefit to industries that make use of aluminium wire as electrical wiring, cables, spokes for wheels, stringed musical instruments, paper clips and tension-loaded structural components and also automotive sector. This will help them determining the extent of tensile loading that the aluminium wires their working on can withstand before failure can occur

Analysis, Validation and Optimization of the Multi-Stage Sequential Wiredrawing Process of EN AW-1370 Aluminium

For the wiredrawing of aluminium, the initial wire rod is obtained by continuous inverted casting. The raw geometry is industrially processed in a linear multi-step wiredrawing sequence to obtain a wire that is commonly used for the manufacture of electrical conductors. In the present work a complete study of the material has been made. The experimental procedure consisted in the realization of a sequence of section reduction stages in the laboratory, a sequence designed following the technological criteria recommended by the manufacturer of the drawing machine in which the industrial process will be implemented. From the specimens corresponding to each reduction step, it has been possible to know the evolution of the main mechanical properties when this pure aluminium is processed by wiredrawing. This information has led to establish the hardening law by which it is possible characterize the plastic behaviour of this pure metal when it is transformed by this specific sequential process of cold forming. The strain hardening law has been implemented in a numerical simulation software application and the experimental setup has been simulated for its validation. Finally, the classic analytical solution founded in the “slab method” has been applied for the design of a proposal for the optimization of the industrial wiredrawing process

The influences of the variable speed and internal die geometry on the performance of two commercial soluble oils in the drawing process of pure copper fine wire

The cold wiredrawing process constitutes a classical-tribological system in which a stationary tribe-element (die) is in contact with a tribe-element in relative motion (wire) and both interacting with the interfacial tribe-element (lubricant). This condition is reflected in the effect of friction as a function of the drawing speed and temperature, and directly affects the wearing of the surface into the die and the final quality on the drawn wire. The aim of this work has been to determine the best conditions to process ETP-copper using two different types of oil/water emulsion lubricants. For this purpose, six different die geometries have been proposed and a set of tests have been carried out at different speeds (between 1 and 21 m/s) to determine those combinations that give a lower value in the required drawing force (Fd). The experiments allowed to know the friction coefficient (µ), the temperature profile inside the drawing die and in the lubricant and also the mean roughness (Ra) in the drawn product. The results have shown that drawing speeds above 10 m/s significantly decrease the drawing force and, as a consequence, the friction effect on the interface. The best results have been achieved in the combinations of the lower die angle (2β = 14°) with drawing speeds between 17 and 18 m/s with both types of lubricants used, obtaining the lower values of the friction coefficient between µ = 0.10–0.15 with the lubricant type D (Agip S234-60 oil at 7% concentration). It has been found that those tests carried out with dies with a smaller approach angle have generally made it possible to obtain better qualities in the final product. Additionally, FEM simulations have been done to analyse those cases with the lower values of µ, throwing values of Fd that are consistent with those measured in the experimental setting and allowing to better understand the behavior of the material as it passes through the die

Atomistic Simulation of Crystal Change and Carbon Diffusion during Drawing of Pearlitic Steel Nano-sizedWire

Wire drawing is an efficient material processing technique for metals. Pearlitic steel is recognized as one of the most reliable and strong wire materials for industrial use. The microstructure of the pearlite phase, however, is quite complicated, with a lamellar structure containing alternating nanometer-thick layers of ferrite and cementite. In the present study, three-dimensional wire drawing models for pearlitic steel, in which a cementite layer occupies one half or one third of the wire cross section, are used in molecular dynamics simulations of the Fe-C system based on a pairwise potential. The results indicate that a body-centered cubic to face-centered cubic phase transition occurs in the ferrite layer during drawing. It is found that compressive hydrostatic stress is required to drive this phase transformation. The phase transition is followed by the formation of dislocations and grain boundaries. Cementite has an orthorhombic crystal structure and is more difficult to plastically deform than pure ferrite. During drawing of a pearlite wire, the large deformation of the ferrite layer compensates for the poor deformability of the cementite layer. The carbon content is important in pearlitic steel because carbon atoms can diffuse through all phases. As a indicator of the amount of carbon diffusion, the mean square displacement of carbon atoms is used. It is found that diffusion perpendicular to the ferrite/cementite interface tends to take place suddenly, but the total amount of diffusion is still less than that in the parallel direction

Atlas Steel, Inc. v. Utah State Tax Commission : Brief of Appellee

On Appeal From the Utah State Tax Commission Appeal Nos. 95-0604 and 98-004

Spiral tube decorations on garments: Restoring a lost technique

Spiral tubes made from coiled wire have been used as decorative elements on garments in Estonia for the last thousand years (from the 10th to 19th centuries). Decorations using this technique can be found in both archaeological and ethnographic collections. The tradition documented in Estonia is part of a larger phenomenon that spread across the eastern shores of the Baltic Sea (Finland, Northwestern Russia, Latvia, and Lithuania, in addition to Estonia) from the 6th century AD. Thus far, archaeologists have regarded spiral tube decorations mainly as a source for garment history, and not much attention has been paid to understanding their construction. This article focuses on the techniques used to make spiral tube decorations, from wiredrawing to constructing the ornaments. The results from metal analysis prove that the main raw materials used in wiredrawing have been copper alloys, with additives being mainly zinc and tin, and in lesser amounts, lead and other elements. Woollen and linen yarn and horsehair have been used as materials for constructing patterns. The woollen yarns used are usually fine and of high quality. Two main techniques used to make the ornaments can be observed: weaving the spiral tubes into a tablet-woven band and the use of various types of braided mesh and bands. When considering this very long period as a whole, it is possible to discern many regional differences both in techniques and pattern combinations. Behind the archaeological examples, makers of different skill levels and with different purposes can be seen, from professional craftsmen to women who made spiral tube decorations at home for personal use. Keywords: Spiral tube decorations, ancient craft, tabletwoven bands, archaeological textile

Electrodiffusion Method of Near-Wall Flow Diagnostics in Microfluidic Systems

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The electrodiffusion technique has been mostly used for the near-wall flow diagnostics on large scales. A novel technique for fabrication of plastic microfluidic systems with integrated metal microelectrodes (called technique of sacrificed substrate) enables us to produce microfluidic devices with precisely shaped sensors for wall shear stress measurements. Several micrometer thick gold sensors built-in a plastic substrate exhibit good mechanical resistance and smoothness. Proper functioning of prepared chips with microsensors has been first tested in various calibration experiments (polarization curve, sensor response to polarization set-up, steady flow calibration, temperature dependence of diffusivity). Our first results obtained for separating/reattaching flow behind a backward-facing step and for gas-liquid Taylor flow in microchannels then demonstrate its applicability for the detection of near-wall flow reversal, the delimitation of flow-recirculation zones, and the determination of wall shear stress response to moving bubbles. Other applications of these sensors in microfluidics (e.g. characterization of liquid films, capillary waves, bubbles or drops) can be also envisaged

Analysis of Shear Strength Variance of PH 15-7 Mo Blind Rivet Stems for Aerospace Applications

This project attempts to reduce manufacturing costs incurred to Cherry Aerospace by variance in material properties. To track and predict the shear strength of PH 15-7 Mo stainless steel rivet stems throughout the heat treatment process, samples were taken from several steps in the manufacturing process and experimental heat treatments were performed across a range of temperatures. The supplied rivet stems were heat treated for four hours at temperatures from 520°C to 560°C, in increments of 10°C. Double shear testing in accordance with ASTM 1312-13A revealed that there is no apparent correlation between the strength of the supplied wire and final shear strength of the wire. It is recommended that samples be tested for impact toughness to better understand the shear behavior of the rivet stem due to the break notch. When examining the effects of composition on mechanical properties, there is a lack of evidence to suggest that any correlation can be made. Even with constant composition, different lots of wire exhibit variances in shear strength in the fully heat treated condition. It is concluded that the variances in mechanical properties of the rivet stems are influenced by other factors. These could include manufacturing operations that are not included in the scope of this project, such as stackup of tolerances in the rivet assembly or effects of cold work of the wire prior to procurement by Cherry Aerospace

Networks of People in Specialty Production: Family Firms in the Iron and Steel Wire Industries in Spain (1870-2000)

Capital intensive industries in specialized niches of production have constituted solid ground for family firms in Spain, as evidenced by the experience of the iron and steel wire industries between 1870 and 2000. The embeddedness of these firms in their local and regional environments have allowed the creation of networks that, together with favourable institutional conditions, significantly explain the dominance of family entrepreneurship in iron and steel wire manufacturing in Spain, until the end of the 20th century. Dominance of family firms at the regional level has not been an obstacle for innovation in wire manufacturing in Spain, which has taken place even when institutional conditions blocked innovation and traditional networking. Therefore, economic theories about the difficulties dynastic family firms may have to perform appropriately in science-based industries must be questioned.family firms, spanish economic history, steel wire industries