Papers by Keyword: Drawing

Abstract: This article represents the results of studies of the drawing thin wire from the alloy Pd-5Ni process. The studies used the software developed by the authors using the methods of calculating the drawing process and the computer model implemented in the DEFORM 3D software package. By way of calculation, a drawing route was determined, including 14 transitions, and the efforts of deforming the metal were found when producing wire with a diameter of 0.075. For this mode of deformation processing using the DEFORM 3D software package, we simulated the drawing process and established the temperature and stress distribution over the volume of the workpiece. The simulation results confirmed that the calculated safety factor for drawing is in the range of 2.85-3.43, which ensures a stable process of deformation of the metal without breaks and, as a consequence, an increase in productivity and yield of the suitable metal. Experimental studies have confirmed the adequacy of the developed model, so it can be used to analyze the process of drawing wire from other precious metal alloys. The results of the research are recommended to improve the production technology of thin wire from the alloy Pd-5Ni for the manufacture of catalytic gripping grids.

Abstract: Technological processes have a significant influence on the properties of the metallic formed pieces during production. Due to the plastic deformation, the shape of the component is changed and the degree of the structural anisotropy is increased - the orientation of the grain boundaries in the different parts of the component. It is important to identify these changes, to analyse them and optimize the technological processes. We get an important knowledge of relationship “technological parameters – microstructure – properties”. The article presents the results of the solution of a partial task from this area. It deals with changing of the geometric shape of the component when it is deformed. Specifically, the tubes (material EN SPT 360, STN 411 353) were drawn through the dies with different reduction angles. The dimensions (length and angle), roundness, cylindricity, coaxiality and surface roughness were evaluated.

Abstract: Drawing is characterized by non-uniform character of plastic deformation, which is transferred from the die to the processed wire. Such impact causes specific change of wire microstructure. In the surface area the thin layer with highly deformed grains is observed. It is important to measure the thickness of this thin layer. For this purpose it is proposed in this paper to use the value of coefficient of anisotropy, which is calculated as the ratio of mean quantity of phase particles, crossed by secant line perpendicular to deformation axis on the unit of secant line length to the mean quantity of phase particles, crossed by secant line parallel to deformation axis on the unit of secant line length. Distribution of coefficient of anisotropy, both for low and high carbon steel wire after drawing, was obtained by Thixomet PRO software. It made it possible to calculate the thickness of highly deformed area automatically taking into consideration the difference of steels microstructure.

Abstract: Drawing is the basic operation of wire manufacturing. At drawing a wire contacts with a die resulting in decrease of its diameter. During this interaction wire microstructure changes, especially on the contact area between a die and a wire. Specificity of microstructure changing on outer surface of carbon steel wire at drawing and its combination with torsion is presented in the paper. Using optical microscopy, it was found out that in the outer surface of carbon steel wire a narrow layer of highly deformed grains is formed. It is shown that thickness of this layer depends on the deformational processing intensity and is very specific depending on carbon content of the wire.

Abstract: Architectured copper clad aluminium composites processed by a restacking drawing method at room temperature are reported in this work. Wires were drawn to severe plastic strain without any intermediate annealing. Three different diameters were studied in order to examine the influence of a different plastic deformation level on the structure of the different wires. Thanks to image processing it has been shown that independently of the plastic deformation, inserted fibers remain continuous and are homogeneous in size and shape. Furthermore, XRD and TEM characterizations confirm that there is no significant intermetallic growth during the deformation. Thus, the improvement and/or degradation of the functional properties of the wires can be well controlled by performing an appropriate post-processing annealing treatment. Keywords: Cu/Al composite, architectured wire, drawing, microscopy, image processing

Abstract: The article discusses the process of wire drawing of circular cross-section. The study of stresses of wire drawing in conditions of plane plastic flow was held. As theoretical framework the study was adopted the method of characteristics, a special case, having the definitive decision. Stresses during wire drawing are defined by decomposing the decision into two components of plane strain and the superposition of these decisions. The results of theoretical solution of the problem of wire drawing were used to determine the coefficients of friction on the surface of contact of the tool and the work piece during the deformation of steel with a diameter of 5.5 mm. It is recommended to use two-dimensional methods of solution in the analysis of the process of wire drawing in conditions with a high hearth of plastic deformation (with the relative height of the hearth of plastic deformation 2 and bigger). The theoretical dependences between the friction coefficients at the contact surface of the work piece and the tool was obtained. The obtained values of coefficients of friction can be used over solving the task of the wire drawing in conditions with a high hearth of plastic deformation.

Abstract: At present time tendencies in the development of engineering and technologies in the manufacturing the metal ware need the effective complex impact on material microstructure by methods of different nature. Special attention should be paid to the combined processes of deformational treatment which are constructed on such basic operations as drawing, rolling, pressing, etc. Despite a plenty of studies and high efficiency of combined methods the problem of understanding the scientific grounds for choice the processing parameters which ensure the guaranteed level and high stability of metals and alloys properties has not been solved jet. Medium carbon steel is used for a wide range of metal ware products. Medium carbon steel wire with 0.5 %C was chosen for the experiments. It was subjected to different kinds of deformational processing such as tensile deformation, alternating bending, twisting and their combination. Complex of experimental research was carried out in order to study the influence of different kinds of plastic deformation on the medium carbon steel wire microstructure. By scanning electron-microscope analysis the peculiarities of pearlite behavior after deformational processing with different total deformation degree were studied. The comparative analysis of cementite changing after different kinds of deformation was conducted.

Abstract: Because basic metal forming methods have reached the maximum of their manufacturing capabilities in deformation-velocity processing modes so called combined or integrated processing methods move to the forefront. The method of combined deformation processing based on drawing with bending and torsion deformation was developed. On the example of carbon steel wire it was shown that microstructure and mechanical properties can vary in a wide range depending on the process regimes. In order to estimate the probability of carbon steel wire fracture at the designed combined deformation processing the simulation complex DEFORM-3D was used. The results demonstrate that there are no areas with high concentrations of hydrostatic pressure and overestimated values Cockcroft-Latham criterion. For the developed combined deformation processing of wire by drawing with alternating bending and torsion, algorithm for the prediction of carbon steel wire microstructure and mechanical properties changing at combined deformation processing was carried out. The developed methodological approach to forecasting of formation of the structure and mechanical properties during combined deformation processing of carbon steel can be used to solve both direct and inverse problems.

Abstract: The obtained phenomenological model of hardening G3Si1 and Sb08-G2S low-carbon welding wire during multistage drawing establishes the dependence of the hardening curve coefficients (hardening index and hardening modulus) on the integral tensile strain. The obtained model makes it possible to calculate the hardening curve, strength, and plasticity indicators of metal products based on the results of wire rod testing in the delivery state.

Abstract: Using electron backscatter diffraction (EBSD), the relationship between deformation textures, developed upon different stress-strain states and characterized by the basic crystallographic orientations of recrystallized grains, has been studied in a FCC metal. The regularities of recrystallization twins development were considered. Crystallo-geometric relations between the deformation and the recrystallization orientations were explained with the mobility of the special grain boundary close to the coinciding site lattice boundary Σ25b. Mechanisms of nucleation and growth of the annealing twins were proposed.