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This paper discusses different techniques for making copper wire in the fourth and third centuries BCE in ancient Macedonia (Northern Greece). Wire was used to form stems on gilded wreaths, and to support berries, leaves and rosettes. Stems were made in one piece with the leaves, and are likely to have been formed in at least two ways: one involved cutting them out of sheet copper about 0.5 mm thick, which was creased and then hammered into shape; the other involves using copper rods 1mm square. Some of the square copper rods can be seen on the wreaths, and their regularity suggests they may have been formed on a swaging block. Berries were joined to the wreath circlets by round wires, formed in some cases, it is suggested, by hammering sheet metal around a central core; in other cases, these stems may have been formed by rolling a rod between stone slabs. No evidence, such as longitudinal striations, was found of drawing. Some examples of strip-twisted wire were found, but there are fewer cases of this than of wire formed by hammering. The most expensive gilded wreaths at Derveni, cist grave A, Phoinikas cist grave 5 and Sedes, sometimes had special features, such as gilded copper tubes (‘branches’) with smaller stems on either side, or square wires formed into spirals.

This paper discusses different techniques for making copper wire in the fourth and third centuries BCE in ancient Macedonia (Northern Greece). Wire was used to form stems on gilded wreaths, and to support berries, leaves and rosettes. Stems were made in one piece with the leaves, and are likely to have been formed in at least two ways: one involved cutting them out of sheet copper about 0.5 mm thick, which was creased and then hammered into shape; the other involves using copper rods 1mm square. Some of the square copper rods can be seen on the wreaths, and their regularity suggests they may have been formed on a swaging block. Berries were joined to the wreath circlets by round wires, formed in some cases, it is suggested, by hammering sheet metal around a central core; in other cases, these stems may have been formed by rolling a rod between stone slabs. No evidence, such as longitudinal striations, was found of drawing. Some examples of strip-twisted wire were found, but there are fewer cases of this than of wire formed by hammering. The most expensive gilded wreaths at Derveni, cist grave A, Phoinikas cist grave 5 and Sedes, sometimes had special features, such as gilded copper tubes ('branches') with smaller stems on either side, or square wires formed into spirals. [ABSTRACT FROM AUTHOR]

In thiswork, a 24-month two-batch fuel management strategy for the APR1400 using LEU + has been investigated, where enrichments of 5.9 and 5.2 w/o are utilized in lieu of the conventional 4–5 w/o UO2 fuel. In addition, an Accident Tolerant Fuel (ATF) clad based on the swaging technology is applied to APR1400 fuel assemblies. In this special ATF clad design, both outer and inner SS316 layers protect the conventional zircaloy clad. Erbia (Er2O3) is introduced as a burnable absorber with two-fold goals to lower the critical boron concentration in the long-cycle LEU + loaded core as well as to handle the LEU + fuel in the existing front-end fuel facilities without renewing the license. Two types of fuel assemblies with different loading of gadolinia (Gd2O3) are considered to control both the reactivity and the core radial power distribution. The erbia burnable absorber is uniformly admixed with UO2 in all fuel pins except for the gadolinia-bearing ones. In this study, two core designs were devised with different erbia loading, and core performance and safety parameters were evaluated for each case in comparison with a core design without any burnable absorbers. The core analysis was done using the two-step method. First, cross-sections are generated by the SERPENT 2 Monte Carlo code, and the 3-D neutronic analysis is performed with an in-house multi-physics nodal code KANT.

The critical study is focused on improving ductility by maintaining higher strength of swaged Zircaloy-4 through specifically optimized annealing treatment. It has led to evolution of texture to obtain stable (21¯1¯0) pyramidal type in the microstructure, enhanced elongation up to ∼20%. An excellent combination of ductility and strength was achieved through low-strain-swaging followed by annealing optimization, unlike other resource-intensive and conventional SPD techniques. Improvements in mechanical properties, especially ductility enhancement, were substantiated with the detailed and targeted microstructural analysis with EBSD and TEM.

Electron microscopy is used to study the evolution of microstructure of copper–aluminum composites, which takes place as the degree of reduction upon rotary swaging increases, and their conductivity is measured. The effect of reinforcing the copper–aluminum composites with steel fibers on the conductivity is studied. [ABSTRACT FROM AUTHOR]

The present study aimed to discover the effect of cold swaging reduction on the bulk gradient structure formation and mechanical properties of a 316-type austenitic stainless steel. The initial rod was subjected to radial swaging until 20–95% reduction of initial rod diameter, at room temperature. According to finite element simulation, higher plastic strain was accumulated in the surface layer compared to the center region during swaging. Microstructural investigations revealed three-stage gradient structure formation in the center and edge regions of the deformed rod. Meanwhile, cold swaging resulted in the development of strong 111ǁBA, 001ǁBA, and weak 111ǁBA texture components in the center and edge, respectively. Significant tensile strengthening was observed after cold swaging. For instance, the yield strength (YS) increased from 820 MPa to 930 MPa after 40–80% reduction respectively, without the loss of ductility (δ–14%). This unique aspect of the mechanical behavior was attributed to the gradient structure of the cold swaged material and explained in detail. [ABSTRACT FROM AUTHOR]

The swaging quality of self-lubricating spherical plain bearings (SSPBs) has an important influence on the safety of the aircraft. The roller swaging process has an edge on other swaging processes in low swaging load and high swaging quality. The 3D elastic–plastic finite element model of roller swaging and push-out test were developed, and the influence of the roller swaging process loading parameters, such as the swaging time, the swaging load and the rotation speed of the roller tool on the push-out load, the gap between the flanging lip of the V-groove and the housing chamfer, and the radial displacement (the inner surface of the outer ring) after roller swaging were studied. Finally, the roller swaging test was conducted, and the test results were compared with the simulation results. The research shows that the test results are consistent with the results of the simulation model, and with the increase of the swaging time, swaging load, and rotation speed of the roller tool, the gap will be increased as well, resulting in an increase in the push-out load. However, the excessive swaging load and rotation speed of the roller tool will increase the radial displacement, which will result in a reduction in the rotation flexibility of the bearing. Under the conditions of reasonable swaging time and swaging load, a good swaging quality can be obtained by controlling reasonable rotation speed of the roller tool. [ABSTRACT FROM AUTHOR]

The increased interaction time between the implant and the human body has led to the search for new materials used in the manufacture of implants. In this way, β-Ti alloys free of toxic elements have gained prominence, such as Ti-40Nb. In this work, an alloy ingot was swaged and bars with 10, 8 and 7 mm diameter were obtained. All conditions, including as-cast, had their microstructure characterized by x-ray diffraction, optical microscopy, scanning electron microscopy and transmission electron microscopy (TEM). Mechanical and physical properties were evaluated by Vickers microhardness and elastic modulus measurements. The results showed that the swaging process reduced the Vickers hardness and elastic modulus, respectively, by 31 and 19% for the Ti-40Nb alloy, around 187 HV and 61 GPa (SW8). In addition, using the TEM technique, phase separation (spinodal decomposition) was detected, as well as stress-induced omega, both at the nanoscale. [ABSTRACT FROM AUTHOR]

Commercially pure(CP) Ti fabricated by 135° ECAP and swaging was annealed at 100, 150, 200, 250, 300, 350, 400, 450℃ and 500℃ for 1h, respectively. The microstructure and properties of annealed commercially pure Ti were investigated by transmission electron microscopy, scanning electron microscopy, uniaxial tensile test and microhardness test. The results show that when annealing temperature is below 400℃, dislocation density reduces gradually and grain boundary becomes clear, no obvious change occurs in the microstructure,ultimate tensile strength and microhardness decrease slightly and no obvious increase occurs in the elongation;when annealing temperature is above 400℃, recrystallization occurs with the increase of annealing temperature, and the grain size increases obviously, the average size is about 5μm, the ultimate tensile strength and microhardness decrease significantly and elongation increases at the same time. The tensile fracture shows the tensile fracture of annealed commercial pure Ti by ECAP and swaging is ductile fracture. With the increase of annealing temperature, the size and depth of dimples increase.

Abstract The research aims to analyze the impact that severe plastic deformation arising during Rotary Swaging has on mechanical properties and corrosion resistance of a near-α-titanium alloy Ti-2.5Al-2.6Zr (Russian industrial name PT7M). The nature of corrosion decay in fine-grained alloys caused by hot salt corrosion is known to vary from pit corrosion to intercrystalline corrosion at the onset of recrystallization processes. Resistance to hot salt corrosion in a fine-grained titanium alloy Ti-2.5Al-2.6Zr is shown to depend on the structural-phase state of grain boundaries that varies during their migration as a result of "covering" corrosive doping elements (aluminum, zirconium) distributed in the crystal lattice of a titanium alloy. Highlights • Fine-grained (FG) structure in near-α-alloy Ti-2.5Al-2.6Zr was formed with Rotary Swaging. • Hot salt corrosion mechanisms in coarse-grained (CG) and FG alloys are studied. • Corrosion defects of type I in a CG alloy are stitched as a result of β-phase particles precipitation. • Corrosion defects of type II in a CG alloy look similar to intercrystalline corrosion (ICC). • Corrosion decay in a FG alloy changes from pit corrosion to ICC when the migration of grain boundaries starts. [ABSTRACT FROM AUTHOR]

There is an increasing demand in the industry for conductive high strength copper alloys. Traditionally, alloy systems capable of precipitation hardening have been the first choice for electromechanical connector materials. Recently, ultrafine-grained materials have gained enormous attention in the materials science community as well as in first industrial applications (see, for instance, proceedings of NANO SPD conferences). In this study the potential of precipitation hardened ultra-fine grained copper alloys is outlined and discussed. For this purpose, swaging or accumulative roll-bonding is applied to typical precipitation hardened high-strength copper alloys such as Corson alloys. A detailed description of the microstructure is given by means of EBSD, Electron Channeling Imaging (ECCI) methods and consequences for mechanical properties (tensile strength as well as fatigue) and electrical conductivity are discussed. Finally the role of precipitates for thermal stability is investigated and promising concepts (e.g. tailoring of stacking fault energy for grain size reduction) and alloy systems for the future are proposed and discussed. The relation between electrical conductivity and strength is reported.

Nano-sized ZrC dispersion strengthened tungsten alloy (W-0.5wt%ZrC) rods with enhanced mechanical properties and superior high-temperature stability were fabricated by high temperature rotary swaging. The effects of swaging and annealing on the microstructure and mechanical properties of W-0.5wt%ZrC alloys were investigated. The as-swaged W-0.5%ZrC rod showed noticeable ductility at 200 °C with a total elongation of 4.2% and a tensile strength of 724 MPa, and at 500 °C the strength remains as high as 547 MPa and the total elongation is 28%. The ductile-to-brittle transition temperature (DBTT) is about 200 °C. The recrystallization start temperature of swaged W-0.5wt%ZrC is about 1500 °C, which is about 300 °C higher than that of rolled pure W. The possible mechanisms for the enhanced mechanical properties and thermal stability were discussed. [ABSTRACT FROM AUTHOR]

Highlights • Current status of Charpy impact properties of pure and modified W materials are reviewed. • Impact properties of W are dependent on fabrication methods and histories regardless of their major chemical composition. • DBTT and USE of pure W from different production routes could be integratedly understood using Hall-Petch type relations. Abstract One of the most critical issues affecting tungsten (W) as plasma facing material is ductile-to-brittle transition behavior. It is well known that the microstructure of W materials is influenced by the fabrication methods and histories, which can affect those behaviors. In this paper. the current status of Charpy impact properties (ductile-to-brittle transition temperature (DBTT) etc.) of pure and modified W materials fabricated by several methods and histories are reviewed based on the open literatures and the possibility of integrated interpretation of Charpy impact properties of W materials from different production routes is discussed. [ABSTRACT FROM AUTHOR]

TiC reinforced titanium matrix composites are promising for advanced applications. Generally, the relative density of the composites and the interfacial bonding between the matrix and reinforced particles may have a great influence on the mechanical properties. This study presented the fabrication of the full-densified Ti-15Mo-xTiC (x = 1.5, 3.0, 4.5 wt%) composites through in-situ reactive sintering of Ti, Mo, and MoC powders and hot swaging process. Experimental results show the formation of TiC and the absence of MoC in the fabricated composites. After hot swaging, the TiC particles showed aligned distribution along the swaging direction, and exhibited well bonding with the β-Ti matrix. Increasing the TiC content leads to increase tensile strength and Young's modulus but decrease elongation. Ti-15Mo-4.5TiC offers and outstanding combination: ultimate tensile strength = 1290 MPa, yield strength = 1075 MPa, Young's modulus = 89 GPa, and tensile elongation = 3.1%. The strengthening effect is attributed to Mo solid solution in Ti matrix, β-Ti grain refinement, and TiC particle reinforcement. The specific contribution of each mechanism is quantitatively calculated, showing good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

A lightweight reliable joint is required for the selflubricating spherical plain bearing which is widely used in aerospace as a key flexible connection. And the roller swaging is a promising process for obtaining the lightweight reliable joint by the plastic deformation. The experimental setup of the roller swaging assembly process and the push-out load inspection tooling were designed and fabricated in this paper. Moreover, the 2D elastic-plastic FE models of roller swaging and push-out test were developed under the Abaqus/Explicit environment for obtaining the metal flow and equivalent strain distribution during the processes. The good agreements of joint condition and push-out load are highlights between the FE simulation and experiment. Based on the results, the optimum designs of the housing chamfer height a and angle a and roller feed distance h were carried out with a typical roller angle ß(60°). It can be found that the little chamfer height and angle are beneficial to obtain a good joint condition. However, compared with 45 and 60°, the load-carrying capacity of chamfer angle 30° is reduced by 30% at least. And the inward displacement of the outer race inner surface for chamfer height 0.7H is more than 50% larger than the ones of 1.0H and 1.2H. What is more, the larger roller reduction will enhance the load-carrying capacity and improve the joint condition, but result in a heavily inward metal flow. [ABSTRACT FROM AUTHOR]

A rotary swaging process is presented which allows the manufacturing of smart structures by forming hollow shafts and joining sensor elements simultaneously. A reasonable form- and force-fit of the sensor element is required to ensure the desired sensory properties of the structure, such as linearity, long-term stability and repeatability. However, the conjoint forming process is subjected to uncertainty which leads to fluctuations of the sensor loads and the remaining pre-tension forces. In order to increase the adjustability and accuracy of the process, the utilization of the sensor signals for a control approach is investigated. The infeed and the mandrel force are found to be potential control parameters and the possible time slot of an intervention is identified. A first control approach is implemented and shows an improvement in accuracy of around 65% compared to the uncontrolled process. [ABSTRACT FROM AUTHOR]

A TA15 matrix composite reinforced by 3.5 vol.% TiB whiskers with a network microstructure was fabricated by the reaction hot pressing method. After sintering, the composite developed a net-like microstructure. To improve the mechanical properties, a cylindrical billet of the as-sintered TiBw/TA15 composite was subjected to upsetting and swaging operations with intermediate heating at 1000°C. The original equiaxed network units were stretched slightly, and the matrix had a microstructure evolution from a basket structure to a bi-modal structure after hot forging. The results of tensile tests at room temperature showed that the ultimate tensile strength and elongation of the composite increased by 8.2% and 130%, respectively, while the yield strength appeared to remain constant. Furthermore, the mechanical properties of the as-forged composite also improved at an elevated temperature. [ABSTRACT FROM AUTHOR]

In the present work, sintering and cold swaging of 92.5W-5.25Ni-2.25Fe heavy alloys prepared from various grades of W powder were investigated. The mean particle sizes of the W powder grades were 3.4 µm, 10.5 µm, and 28.0 µm. It was observed that linear shrinkage decreased with increasing W particle size. The sintering behavior of the alloys was discussed in terms of liquid capillarity and W particle size. The alloy prepared from the 28.0-µm grade W powder exhibited incomplete densification. This alloy could not be swaged because of the poor mechanical properties. The alloys of the other grades were fully densified. They exhibited better ductility and swageability. The alloy of the 10.5-µm grade W powder had good mechanical properties (e.g., tensile strength 1300 MPa, hardness 38 HRC after 10% cold swaging) that were equivalent to those of the alloy of the fine-grade W powder (3.4 µm). [ABSTRACT FROM AUTHOR]

Influence of mechanically alloyed tungsten-rhenium powders on the microstructure and mechanical properties of liquid phase sintered 89W-7Ni-3Fe-1Re heavy alloy was studied. Heat treatment and swaging were conducted on alloys prepared using both conventionally blended and mechanically milled powders. The results indicated the formation of bcc solid solution by high energy milling of tungsten and rhenium powders. The corresponding particle and the crystallite size decreased after high energy milling. Grain size and contiguity of the milled alloy were significantly lower than those of conventional counterpart. The alloy prepared using high energy milled W-Re powder exhibited relatively superior balance of strength, ductility and impact toughness. These findings suggest that refractory powder mechanical alloying prior to sintering is beneficial for improving the mechanical properties of tungsten heavy alloys. [ABSTRACT FROM AUTHOR]

Umbilical cables are important components in underwater oil extraction, providing electro-hydraulic connection between platform and manifold in oil well, through elements such as electrical cables and thermoplastic hoses. The connections of thermoplastic hoses are made with fittings installed by a cold forming process, called swaging, to ensure a perfect seal. These fittings are made of SAE AISI 316L stainless steel, but in order to reduce manufacturing costs, SAE AISI 1045 carbon steel fittings are used in hose factory acceptance tests. However, longitudinal cracks were produced during swaging of carbon steel of a specific supplier. In this work, samples from two different suppliers were characterized before and after installation to understand the failure cause. The characterization was made by visual inspection, dimensional control, hardness tests, chemical composition, microstructural and fracture surface analyses. In addition, swaging process simulations by finite element method (FEM) using a commercial software were performed. The results indicated large variations in material elements percentage from the supplier with failed connections history. This fact resulted in elevated amounts of non-metallic inclusions which promoted the cracks. Finally, corrective actions were recommended to mitigate the failure occurrence. [ABSTRACT FROM AUTHOR]

A process sequence enabling an efficient production of hollow sensory machine elements with adapted wall-thickness and a smooth outer contour is presented. The applied conjoint forming approach aims to simultaneously form a tubular part to its final shape whilst integrating a functional element into it. Additionally, the forming process is adjusted in order to set up a pre-tension in the assembly. Thus, a lift-off of the sensor element in case of tensile forces during application is prohibited and a high sensor linearity is ensured. In order to predict the achievable pre-tension and to determine the maximum process force, a three-dimensional numerical model is introduced. The underlying mechanisms of the pre-tensioning process are discussed on the basis of a forming process with and without a mandrel. A direct comparison of the two basic swaging strategies – recess and infeed swaging – reveals advantages of the infeed swaging strategy to achieve a high pre-tension of the assembly. The cold work hardening of the preform, the thermal heating and the machine stiffness are relevant phenomena of the process which influence the forces significantly. A detailed validation proves the necessity to include the mentioned effects in the numerical model. Furthermore, a trial of a sensory rod is presented. The high linearity of the sensory structure underlines the high potential of the proposed process to integrate sensor elements into massive metallic structures. [ABSTRACT FROM AUTHOR]

There is an increasing demand for precipitation-hardened Cu-Ni-Si alloys in the industry, where the high strength and moderate electrical conductivity are required. The main objective of this study was to apply a combination of microstructure refinement using swaging (SW) to generate an ultrafine-grained (UFG) microstructure in Cu-2.5 wt%Ni-0.5 wt%Si-0.06 wt%Mg (Cu-2.5Ni-0.5Si-0.06Mg), along with an optimized precipitation hardening. As a result, a substantial improvement of mechanical properties of the swaged samples (UFG condition) after precipitation hardening is apparent as compared to the precipitation-hardened non-swaged samples (coarse-grained (CG) condition). The mechanical properties of the UFG state are significantly superior to those of the CG state, i.e., a sharp increase in the elongation to fracture of 14% and a tensile strength of 800–900 MPa can be achieved. This study summarizes a detailed description of the microstructure after different processing steps using optical microscope (OM), electron channeling contrast imaging (ECCI) methods, and transmission electron microscopy (TEM), and presents the consequences on the most important mechanical properties such as the strength and ductility. [ABSTRACT FROM AUTHOR]

Connection technique of copper and aluminum is a key challenge in refrigeration industry. In this paper, rotary swaging connection process is proposed to connect cooper tube and aluminum tube in physical way. We find the length of overlapped area has a great effect on the joint reliability, and it should exceed the deformation region length. The joint strength is approximately determined by necking. With the reduction of the diameter at the necking area, joint strength first increases and then decreases. Some experiments are carried out to test the joining strength. It is shown that the joints are reliable enough, and joining by rotary swaging method is effective to combine copper and aluminum tubes. [ABSTRACT FROM AUTHOR]

Roller swaging is an assembly process of self-lubricating spherical plain bearings, which provides a lightweight reliable joint by means of the plastic deformation with a small forming load requirement. The precise process control of the roller swaging is of great significance to ensure the assembly reliability and a good performance of the self-lubricating spherical plain bearing. In present investigation, the forming load analytical equations for various process parameters was proposed by a plane strain analysis considering the existence of a rigid end, which is a key mechanical factor that causes the metal flow in the roller swaging process. The effects of the feed distance, roller angle, feed speed and friction coefficient on the forming load are assessed in detail. What’s more, the metal flow in the roller swaging was revealed by a 3D elastic-plastic finite element model. The forming load was also obtained from the finite element model during the roller swaging process. Finally, the roller swaging assembly experiments were conducted with a roller swaging apparatus in laboratory conditions, and the good agreements are highlighted among theoretical calculation, FE simulation and experiment measured. [ABSTRACT FROM AUTHOR]

The corrosion of Ti-54M titanium alloy processed by hot rotary swaging and post-annealed to yield different grain sizes, in 2 M HCl solutions is reported. Two annealing temperatures of 800 °C and 940 °C, followed by air cooling and furnace cooling were used to give homogeneous grain structures of 1.5 and 5 µm, respectively. It has been found that annealing the alloy at 800 °C decreased the corrosion of the alloy, with respect to the hot swaged condition, through increasing its corrosion resistance and decreasing the corrosion current and corrosion rate. Increasing the annealing temperature to 940 °C further decreased the corrosion of the alloy. [ABSTRACT FROM AUTHOR]