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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 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]

Long-length bimetallic conductors with a copper core and a shell from an aluminum alloy up to 2.4 mm in diameter with enhanced strength are obtained by swaging. The effect of the swaging strain on the structure, phase composition and mechanical properties of the bimetallic conductors is studied. [ABSTRACT FROM AUTHOR]

Production of Zirconium alloys for nuclear power reactor comprises of a number of steps during swaging and each step influences microstructural and mechanical properties of the finished product. The Zircaloy-4 was subjected to cold swaging to reduce its cross section gradually from 23 to 16 mm diameter via several passes of swaging followed by intermediate vacuum annealing at 732 °C for 3 h. EBSD was carried out to study the influence of twinning in the Zr-4 alloy. Twinning is observed in swaged ({11 2 ¯ 2}〈11 2 ¯ 3 ¯ 〉) and annealed ({11 2 ¯ 1}〈11 2 ¯ 6 ¯ 〉) samples. TEM was done to substantiate the role of dislocation density. It is observed that several swaging and annealing treatments have improved tensile strength and fracture toughness of the Zr-4 alloy. [ABSTRACT FROM AUTHOR]

Abstract: The technologies of repairing the worn parts of metallurgical equipment using plastic deformation methods, namely, expansion, swaging, upsetting, pressing, knurling, and forge-rolling, are described. Recommendations are given to choose temperature conditions in repairing the parts and determining the deformation forces. [ABSTRACT FROM AUTHOR]

The structure and properties of magnesium alloy WE43 are studied after homogenizing and rotary swaging deformation conducted in several stages with step lowering of the temperature from 400 to 325°C and increasing the extrusion ratio to 2.56 - 2.78. The deformation yields an ultrafine-grained (UFG) structure with a mean size of the structural components about 500 - 800 nm and particles of aMg41Nd5 phase with a mean size of about 300 - 400 nm. The formation of the UFG structure raises the strength of the alloy. The best combination of mechanical properties is provided by swaging with the final temperature 325°C. It is shown that the rotary swaging deformation does not affect the corrosion rate of the alloy measured by the methods of potentiodynamic polarization, loss in the mass and emission of hydrogen. [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]

Cold-swaging is one of a cold deformation processes, and ceramic-reinforcement nano-composite coatings can effectively improve the performance of metal matrix surface. Therefore, the two processes are innovatively combined to further improve the surface properties of the metal matrix in this paper. The microstructure and surface properties of the laser cladding 316L + 10 wt% SiC nano-composite coatings were examined through designed experiments after cold-swaging by self-developed hydraulic machine. Furthermore, the coatings were compared with those without cold-swaging coatings at the same time. The result shows that the cold-swaging process can further enhance the tensile strength, micro-hardness and the wear resistance of the composite coating. This study can be used as a reference for further strengthening of laser cladding nano-composite coatings in future research. [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]

Hydraulic control actuation systems in launch vehicles use flexible hoses for transmission of forces to actuators at different locations. The hose ends are connected to the interface adapters by AISI 304 stainless steel sleeves. These sleeves are assembled to nipple end fittings of the high-pressure hose by a swaging operation to obtain leak-proof hose assemblies. The swaging operation is carried out at room temperature by a hydraulically operated swaging machine. Performance of the system as a whole requires strict adherence to the quality standards maintaining the critical interface dimensions within specified tolerances and ensuring the compression given to the swaged joint through the sleeve. If the joining forces are less, this can result in loose joints and gross leakage, whereas excessive compression can cause damage to the parts of the system namely the sleeve, stainless steel braid, PTFE or the adapter. The swaged joint is a single-point failure mode, indicating that a failure in the joint can lead to mission failure. It has to withstand harsh environments such as high pressure, low and high temperature extremes, fatigue loading due to pressure cycling as well as vibration. Therefore, as part of design verification, a detailed qualification plan has been prepared and the hoses were tested as per the plan. As per the test plan, these hoses undergo acceptance tests which include pneumatic and hydraulic pressure testing. During acceptance testing of hoses, one of the hose sleeves was found to be cracked. The cracking was observed after carrying out the pneumatic test when the assembly was being prepared for hydraulic pressure set-up. This paper describes the detailed metallurgical investigation carried out to understand the cause of failure and actions taken to avoid similar failures. [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]

This paper summarizes the research work aimed to elaborate a new plating method for axisymmetric metallic parts by precision cold forming on rotary swaging principle and, on this basis, to develop an environmentally friendly technology for net-shape plating. The new technology is intended to create parts with the basic structure made from cheap materials with high fatigue strength, on which, in areas where they require different characteristics (low friction coefficients, greater hardness, greater corrosion resistance, etc.), a layer of more expensive materials that provide these features is applied. At first, the new method of plating through rotary swaging was developed and the net-shape plating technology was preliminarily designed. Then, the experimental technology was analyzed and optimized employing process simulation by finite element method (FEM). A nonlinear finite element analysis (FEA) package, MSC.Marc/Mentat, was used. The full 3D FEM model established in this study eliminates some of the limitations encountered in the previous works using the real movement curve for dies and accurate boundary conditions. The model running tests indicate that the relative positioning between base workpiece and coating tube is of crucial importance in this application. Finally, practical experiments were carried out, the results been used for validation of the 3D simulation model, for physical-mechanical characterization of the joining between base part and coating layer and for technology design finalization. A good agreement between experiments and simulation was found. Also, the experiments indicate that the joint is more tightened when the inside workpiece has a yield strength greater than the outer workpiece. [ABSTRACT FROM AUTHOR]

The effect of the temperature and degree of deformation during warm swaging on the evolution of the microstructure and mechanical properties of preliminarily quenched medium-carbon steel 40KhGNM is studied. It is shown that the deformation produces an ultrafine-grained structure with ferrite grains elongated over the longitudinal direction and fine distributed nanocarbides. [ABSTRACT FROM AUTHOR]

With the development of manufacturing industry, metal tubes and rods are used more and more widely in automobile, aviation, and aerospace fields. Rotary swaging, a competitive plastic-forming technology for manufacturing tubes and rods, can realize net-shape forming for high-quality workpiece. However, in order to control the forming precision of tube or bar workpiece, the complex mechanical system was needed in the conventional swaging machine. In this paper, a rotary swaging process utilizing energy-controlled method is proposed, which can improve the flexibility of the process and control forming diameter of the tubes by changing the forming energy. In the swaging machine, a servo motor and its control system were used to change the speed of the rotary swaging spindle. And then, the swaging energy of the hammer die can be controlled. Rotary swaging experiments of pure copper tubes were conducted on the developed rotary swaging machine. These tubes with outer diameter of 8.0 mm and wall thickness of 1.0 mm were formed to necking tubes with different outer diameters. Meanwhile, the relationship between the speed of the spindle and the forming diameter of the formed tube was obtained. The metallographs of the formed tubes showed the compact structure and continuous streamline. To investigate the metal behavior under different energy of the hammer die, Transvalor Forge 2011 was used to simulate the rotary swaging process of tubes based on energy-controlled swaging method. The metal flows in radial, axial, and circumference directions, emerging axial elongation and necking deformation. Comparing the experimental results with the simulated ones, the deformation condition and thickness distribution are in good agreement. [ABSTRACT FROM AUTHOR]

Residual stress analysis of swage autofrettaged gun barrel is performed in this study via finite element (FE) method. The swage autofrettage technique is one of the modernized pre-stressing methods to enhance the load bearing capacity and fatigue life of all gun barrels. An oversized moving mandrel is forced inside the gun barrel, which deforms the material through physical interference. The process is analyzed by evaluating residual stresses using a commercially available software package. The deformation effects caused by the mandrel and the geometrical variation of the mandrel on the gun barrel are analyzed in this study. This field has been insufficiently researched, but the effect of pre-stressing on the barrel, and at the start and mid-length for the swaging process, is not well examined. Thus, further analysis is required. The variations and effectiveness of the designed pressure band model are shown to define the problem easily. Results are evaluated at mid-length using a fixed fringe width percentage (A defined percentage of gun barrel axial length). The desired effects are well validated through numerical investigation using FE analysis. This study reveals that the geometry should be designed very thoroughly to determine the after effects. If too many variations occur, then the initial force requirement is extremely high; otherwise, the desired swaging effect cannot be achieved. [ABSTRACT FROM AUTHOR]

TIMETAL 54M is a newly developed (α + β) titanium alloy with nominal composition Ti-5Al-4V-0.6Mo-0.4Fe. The alloy can provide a cost benefit over Ti-6Al-4V due to improved machinability and formability. In the present work, evolution of mechanical properties in terms of tensile and hardness values is investigated as a function of deformation degrees imposed via rotary swaging (RS). Microstructure, mechanical properties, and fatigue performance of Ti-54M are investigated after severe plastic deformation by RS conducted at 850 °C and after being subjected to two different post-swaging annealing conditions. Optical microscopy and scanning electron microscopy using electron back scatter diffraction were utilized to document the evolution of the microstructure. Tensile tests were conducted to characterize mechanical properties. RS, to a true strain of 3.0, is found to lead to a marked ultrafine-grained structure of about 1 μm grain size with low content of high angle grain boundaries (HAGBs). Post-swaging heat treatment at 800 °C followed by air cooling did not change the grain size but exhibited high content of HAGBs. Post-swaging heat treatment at 940 °C followed by furnace cooling resulted in a grain size of about 5 μm and enhanced work-hardening capability and ductility, which resulted in less fatigue notch sensitivity, but at the same time lower fatigue strength at 10 cycles. [ABSTRACT FROM AUTHOR]

The spring-back deformation of a head-mounting-block (HMB) after ball-swaging was analytically solved from equations of elasticity. The analytical solution helps to elucidate the mechanism of HMB deformation after swaging and provides insight for designing an adequate HMB with reduced spring-back. This study estimates the displacement of the HMB tip caused by spring-back after swaging, taking the plastic deformation of the HMB into consideration. A suitable boss radius is also discussed. [ABSTRACT FROM AUTHOR]

Multipass forging in dies is used to obtain thin rods 4 mm in diameter from alloy Ti - 6Al - 4V. The properties exhibited by the alloy in this process are described and the possibilities of making fasteners from it are considered. The high strain produced by warm swaging makes it possible to fabricate high-strength fasteners without the expensive and labor-intensive operations of solution treatment and aging. [ABSTRACT FROM AUTHOR]

Fatigue strength of ultrafine-grained commercially pure aluminium (Al 1050) produced by severe plastic deformation (rotary swaging) was investigated. Fatigue tests were carried out on smooth and notched specimens. Results show improved static and fatigue strength of the rotary swaging processed material. However, the processed material was highly notch sensitive due to low work hardening capability, low ductility as well as low uniform strain. It was found that post-deformation annealing above recrystallization temperature can additionally enhance the work hardening capability and the ductility of the swaged material, which led to marked reduction in fatigue notch sensitivity. At the same time, this reduction is accompanied with pronounced loss in strength. Fatigue notch sensitivity of commercially pure aluminium can be good correlated to the work hardening capability and ductility. This behaviour was discussed in details based on microstructure and mechanical properties study. [ABSTRACT FROM AUTHOR]

The rotary swaging process is a cold working process used to reduce the diameter, produce a taper or add point to a round workpiece. For the preform design of a swaged shell nose part by a rotary swaging process, finite element simulation and experimental verification have been carried out to obtain a shell body nose of desired quality. Reliability analysis for the occurrence of process-induced cracks is performed by fault tree analysis. The various process parameters such as initial nose thickness, feed distance and reduction diameter are applied for the fault tree in order to obtain the desired target dimensions. Through simulation, the effects of initial nose thickness on the swaged shapes are analyzed. With fault tree analysis, the risk of process-induced cracks was predicted by finite element simulation and the crack occurrence was verified by swaging experiment. The results show that a swaged shell nose part having higher reliability can be successfully produced by rotary swaging process. [ABSTRACT FROM AUTHOR]

Miniature inner grooved copper tube (MIGCT) is widely applied in industries. To overcome the weak rigidity and strength of MIGCT during stepped tubes manufacturing, rotary swaging process was selected after comparing with radial forging process. The working principle of the rotary swaging was analyzed. A rotary swaging machine, whose workpiece feeding and clamping was respectively driven by an air cylinder and a finger cylinder, was designed. Experiments indicate that the MIGCT was slave rotating with forging dies during rotary swaging. Theoretical analysis was done to investigate the reason of the slave rotation. Experiments were carried out to verify the theoretical analysis. Furthermore, the influences of push force and clamping force on rotation speed were discussed. With the increase of clamping force, the rotation speed of MIGCT decreases gradually in a constant ratio. However, the push force influences the tube rotation speed slightly. In general, it found that an optimal rotation speed of MIGCT is beneficial to the manufacture of the stepped tube. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the influence of hot swaging (SW) and annealing treatment on microstructure and mechanical properties of commercially pure titanium (grade 4) produced by investment casting. During SW at 700 °C, the diameter of the cast titanium bars was reduced from 25 to 8.5 mm in 14 steps. After SW, material was annealed for 1 h at 500, 700, or 870 °C. The as-cast samples showed a typical microstructure consisting of a variety of α-morphologies, while the hot swaged samples exhibited a kinked lamellar microstructure. Annealing at 500 °C did not significantly change this microstructure, while annealing at both 700 and 870 °C led to recrystallization and formation of equiaxed microstructures. The cast bars exhibited a typical hard α-layer in near-surface regions with maximum depth and maximum hardness of 720 μm and 660 HV0.5, respectively. Due to SW, the tensile strength of the as-cast material drastically increased from 605 to 895 MPa. Annealing at 500 °C decreased this tensile strength slightly from 895 to 865 MPa while annealing at 700 °C led to a further pronounced drop in tensile strength from 865 to 710 MPa. No additional decrease in tensile strength was observed by increasing the annealing temperature from 700 to 870 °C. The tensile ductility of the as-cast and hot swaged samples was approximately the same in the range of 0.05 to 0.11, while the annealed samples showed values in the range of 0.25 to 0.53. In addition, the as-cast and hot swaged samples revealed a brittle cleavage fracture surfaces. However, the annealed samples showed a transgranular ductile fracture with formation of dimples. [ABSTRACT FROM AUTHOR]

A practical theory for swaging bored holes within plates and cylinders is proposed which can take into account work-hardening in the presence of small plastic strains based upon equivalent stress-strain data. With the appropriate choice of yield function, this theory applies to the swaging of both thin and thick plates under respective plane stress and plane strain conditions. The theory can be adapted further to the autofrettage of open and closed-ended, thick-walled cylinders where similar plane deformations conditions apply. Here swaging refers to the practice in which an oversized plug or sphere is forced into the bore thereby expanding it permanently to leave a residual circumferential compression in the bore material upon removal of the expanding tool. A similar effect results from applying an initial over-pressure to a long thick-walled cylinder in an autofrettage process. Both treatments are employed to enhance the fatigue resistance when the service loading upon the disc or cylinder amounts to a cyclic, circumferential tension within its bore. Strain gauges bonded to the entry face of the plate are used to monitor the circumferential and radial strain distributions both during and after the swaging process. Experimental results presented for swaging of thin and thin annular discs in aluminium alloy show that the measured residual strain distributions concord with the theory for large discs with a 10/1 diameter ratio. The agreement is less satisfactory with the loss in axial symmetry for parallel-sided lugs with a width to hole diameter ratio of 4/1. [ABSTRACT FROM AUTHOR]

Abstract  In this paper experimental investigations on micro components that are made by rotary swaging are presented and discussed. At first rotary swaging with its most important process variations is explained basically for the macro scale. Afterwards the fundamental changes of the forming of microcomponents are indicated as well as the smaller machines used henceforth. In this context, the shown process limitations and potential errors are very important. The change in microstructure after rotary swaging is shown in selected geometry and materials. The paper concludes with the planned experimental and analytic investigations as well as the machine design modifications for extension of the process limits of micro rotary swaging. [ABSTRACT FROM AUTHOR]

The quasi-static and dynamic mechanical and failure properties of a swaged tungsten-base heavy alloy rod have been investigated, with emphasis on the orientation of the specimens in the rod. Three orientations were considered, 0, 45, and 90 deg, with respect to the longitudinal axis of the rod. Compression, tension, and dominant shear tests were carded out. With the exception of the 0 deg orientation, all the orientations displayed quite similar mechanical characteristics in tension and compression. Dynamic shear revealed a critical strain for adiabatic shear failure of &epsilonc ≈ 0.13, independent of the orientation and quite inferior to the quasi-static ductility. The present study confirms previous results obtained for one (generally unspecified) orientation and extends them to three orientations. Failure mechanisms were thoroughly characterized and it appears that significant damage does not develop prior to final failure. It is concluded that, for practical purposes, the swaged heavy alloy considered here can be regarded as isotropic from a mechanical and failure point of view, in spite of its microstructural anisotropy resulting from the swaging process. [ABSTRACT FROM AUTHOR]

This work investigates the formability of a composite made of a pure aluminium matrix reinforced with an Inconel fibre network. Composites were formed into wires by swaging, to a true strain ɛtrue = 2.7. Thermal expansion, Young's modulus and tensile properties of these wires were measured. Young's modulus of the wires is slightly larger than that of the as-cast composites, indicating that no significant porosity is present in the composite after deformation. Tensile strength and ductility are found to decrease with increasing reduction of diameter. Scanning electron microscope (SEM) observations show that fibres align during swaging and that fibre fragmentation occurs beyond a certain strain. Fibre fragments reach a critical aspect ratio of about 7 after a swaging true strain of 1.5. Qualitatively, the evolution of the properties is explained by a combination of fibre fragmentation and fibre alignment effects. Properties of the wires are discussed using the Clyne model and the Nardone and Prewo model (modified shear lag models). [ABSTRACT FROM AUTHOR]