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

The Influence of Friction Forces in Metal Powders Compaction Process of Stainless Steel 316L

The purpose of this study is to determine as precisely the influence of friction in the compaction of powders, and "conversion" of it, increasing densification. The process is intended to be used in the compaction of hard deformable materials, which increased to approximately 90% densification required very high compaction pressures. These pressures are high, significant wear of the tools produce the compaction and thereby increasing production costs of finished parts from metal powders

Superplastic Behavior of 2024 Aluminum Alloy Sheet Subjected to Thermomechanical Processing

This paper describes the superplastic behavior of the commercial 2024 aluminum alloy. The investigated alloy was processed in a 3 mm thick sheet form. The superplastic properties of the alloy were investigated using an uniaxial tensile testing, with a constant strain rate in the range 8 x 10-4 ÷ 1 x 10-2 s-1, at temperatures in the range 450 ÷ 480 oC. The investigations included the determination of the truestrain, the true-stress caracteristics, the elongation to failure, the strain-rate sensitivity exponent m and the aspect of the alloy microstructure. Elongations to failure longer than 200% for the fine grained 2024 aluminum alloy were obtained at 460o and lower strain rates and at 480 oC and a higher strain rate

Reuse of the Steel Mill Scale for Sustainable Industrial Applications

The purpose of our paper is to assess the reuse potential of the steel mill scale for sustainable industrial applications. We have presented the experimental procedures for chemical and mineralogical characterizations. According to the results of the elementary chemical analysis, the steel mill scale contains the following predominant chemical elements: iron, aluminum, silicon, and magnesium. Due to its high iron content, the steel mill scale can be reused as a source of raw material in the sustainable steelmaking industry. The mineralogical phases identified in the steel mill scale are: wüstite (FeO), hematite (Fe2O3), magnetite (Fe3O4), silica (quartz) (SiO2), magnesioferitte (MgFe2O4), and aluminum oxide (corundum) (Al2O3). Silica, alumina, and hematite are the main compounds of the cement and contribute to the formation of the: dicalcium silicate (2CaO·SiO2), tricalcium silicate (3CaO·SiO2), tricalcium aluminate (3CaO·Al2O3), and tetra—calcium aluminoferrite (4CaO·Al2O3·Fe2O3). The results of the paper are promising and encourage the future research for establishing the optimal percentage for the reuse of the steel mill scale in the composition of concrete

The Behavior of a Zn-Al Anticorrosive Coating in the Wiredrawing Process

The present paper describes and quantifies the behavior of a Zn-Al anticorrosive coating deposited on the surface of a steel wire before its drawing process. For the complete evaluation of this behavior, the drawing of these samples was performed on four wiredrawing lines, differing by the deformation angle 2 · α of the component dies of each line. For good agreement with industrial practice, the drawing series used a partial reduction of the section of 20%. Two aspects were analyzed: the evolution of the chemical composition and the structure of the removed layer during the drawing of the coated steel wire, and the drawing force necessary to carry out this process. This article helps to elucidate how the Zn-Al anti-corrosion layer responds to the stresses inherent in the process of drawing the steel wire on which it is deposited

Fine Electrolytic Tough Pitch Copper Multistage Wiredrawing Pass Schedule Design by Analytical and Numerical Methods

Electrolytic tough pitch copper is commonly used in electric and electronic applications while fine copper wires are widely used in electronic conductors. A multi-pass wiredrawing process was designed for the manufacturing of fine pure copper wire, from 0.50 mm to 0.10 mm in diameter. The analytical model and the finite element analysis (FEA) were performed to validate the pass schedule design. The initial wire was mechanically characterized, and the pass schedule design was stablished by the analytical method according to the specific criteria. The sequence of wiredrawing passes was modeled in the finite element method (FEM) software in order to analyze and validate the designed pass schedule. The combination of these methods allowed designing and validating the wiredrawing pass schedule to implement it in a real process with guaranteed results. This work contributes in showing a combined methodology for the design and virtual validation of the pass schedule in the case of multistage wiredrawing of ETP copper fine wires

Studies on Hot-Rolling Bonding of the Al-Cu Bimetallic Composite

Through the approaches in this article, an attempt was made to analyze the bonding of Al-Cu bimetallic composite layers and the highlight of the diffusion at the boundary between the layers, by hot rolling. An aluminum alloy 6060 plate (EN-AW AlMgSi) and a Cu-ETP ½ hard (CW004A) plate were used. All of these layers of materials were TIG-welded, at both ends, into a heat-treated layered composite and subsequently subjected to the hot-rolling process. The Al-Cu composite material obtained was analyzed by scanning electronic microscopy (SEM) analysis, after being subjected to the tensile test, as well as energy-dispersive X-ray (EDX) analysis. The obtained results highlighted the diffusion at the boundary between the layers of the Al-Cu composite as well as its ductile breakage and the distribution of the amount of Al and Cu at the interface of the layers

Achieving a Toothed Gear on Presses

This paper presents a device that, in final connection with presses, allows toothed gear (with a crown similar to a toothed wheel with right teeth) to be achieved by hot deformation starting from a cylindrical steel bar. For this, finite element simulations were performed in Forge software. The proposed device has 23 rollers, so for the simulation process, a slice representing a part (the 23rd) of a circle which simplifies the essential functionality of this device was taken into consideration