Papers by Keyword: Cast

Abstract: The article presents the results of pilot-industrial experiments in the field of manufacturing technology of contact wire made of Cu-Sn alloys. Cast rods with a diameter of 20 mm, made of CuSn0.04, CuSn0.1, CuSn0.2, CuSn0.3, CuSn0.4 alloys, were obtained in a continuous casting plant on an Upcast system. Cast rods were deformed using a Conform technology, and extruded billets with a diameter of 18 and 20 mm were produced, which were subsequently drawn on a shaped contact wire with a cross section of 100 mm². Cast rods macrostructure and microstructure were studied. The macrostructure quantitative assessment of samples was studied in a cross and longitudinal section. A plot of the effect of the tin content in the alloy on the average grain area in cross section is obtained. An increase in the tin content in the alloy leads to a decrease in the average grain area. An analysis of the rod microstructure in a cross section showed that the structure is a grain of an α-solid solution of tin in copper, and the grain boundaries are thin and clean. After deformation by Conform technology a uniform fine-grained structure is ensured. The effect of the tin content in the alloy on the Brinell hardness of cast billets, made by Conform technology, is determined. An increase in the tin content in the alloy leads to an increase in the hardness of both cast and deformed billets. The microstructure analysis of the contact wire in the cross section is carried out. The mechanical and electrical properties of the contact wire with a cross section of 100 mm² are determined. An analysis of the results showed when the tin content in the alloy is up to 0.4 wt. %, the required level of mechanical and electrical properties of the contact wire is not provided. It may be necessary to change the size of the initial billet before drawing or to increase the tin content in the alloy more than 0.4 wt. %.

Abstract: The Gleeble-3800 unit was used to simulate physically the upsetting of cast and hot rolled semi-finished products from aluminum-lithium alloy V-1461 over the temperature range of 400-460°C and the strain rates of 1-60 s^-1. Following texture analysis of upset samples showed the most typical preferred crystallographic orientations and its formation features depending on the temperature-strain rate schedules. The formation of recrystallization type orientations at a strain rate of 60 s^-1 is a distinctive feature of the cast samples’ behavior during deformation. In general, the established regularities of texture formation allow to produce a hot-rolled semi-finished products from V-1461 alloy with a given structure’s crystallography in compliance with requirements for blank’s forming and product’s operation.

Abstract: The paper presents the methods for forecasting the structure and geometrical parameters of casts by using the ProCAST system of engineering analysis. Based on experimental studies and computer simulation, a regularity between the supercooling rate of aluminium alloy on the one hand and the nucleation rates and crystal growth rates on the other has been established. There have also been established dependencies describing the change in the plasticity modulus, the coefficient of thermal linear expansion, Poisson's coefficient within the temperature range of 20 to 1000°C for cores made from α-set mixture. The computer simulation based on the experimental data of the processing of silumin casts made it possible to forecast the alloy structure with the probability level of 95%, and to calculate the accuracy of hindered contraction of the alloy with accuracy equal to ± 1.5%.

Abstract: The results of physical simulation of hot compression of semi-finished products, selected from a cast ingot and hot-rolled plate from aluminum-lithium alloy V-1461, in the temperature range of 400-460°C and strain rates of 1-60 s^-1 are presented. It is established that at a constant strain rate the flow stresses decrease with increasing test temperature, an increase in the strain rate leads to an increase in flow stresses at a constant temperature. The parameters of the hot deformation rheological model, including the Zener-Hollomon parameter and the hyperbolic sine law, are determined. It is established that the parameters of the rheological model for the cast and hot-rolled state differ insignificantly.

Abstract: Aluminum and its alloys are widely used materials; they are next to steel in use mainly in the automobile industry due to their high strength – to – weight ratio and corrosion resistance beside its other attractive properties. Against their attractive properties; they have the disadvantage of solidifying in columnar structure which tends to reduce their mechanical characteristics and surface quality. Therefore it became customary to grain refine them either by Ti or Ti+B to overcome this discrepancy. In this paper, comparison between Molybdenum addition to commercially pure aluminum grain refined by Ti and Ti+B on its grain size and mechanical characteristics both in the cast and after pressing by the ECAP process is investigated and the obtained results are presented and discussed.

Abstract: The Synthesis of aluminium matrix composites is receiving considerable emphasis in meeting the requirements of various industries. Due to the desired properties such as low weight, high specific strength, good corrosion resistance and excellent wear resistance, they have received a great interest in the recent years. Metal-matrix composites (MMCs) based on aluminium and magnesium has emerged as an important class of materials and Al₂O₃ can be considered as ideal reinforcements, due to their high strength, high aspect ratio and thermo-mechanical properties. The objective of this work is to reinforce Al 1100-Mg alloy with different wt% of Al₂O₃ (0, 3, 6, 9 and 12) was added by melt stirring method and Extrusion is carried out (extrusion ratio of 12.25) for the same alloy and composites. Mechanical property like hardness and tensile properties have been investigated for cast and extruded of base alloy and composites.

Abstract: We chose cast and extrude magnesium alloy AZ61 as materials and studied the influences of temperature, humidity, pressure and NaCl atmosphere on the corrosion products and corrosion mechanism by means of SEM, EDS and XRD. we could indicate the corr osion rate of extruded AZ61 magnesium is faster than that of cast AZ61 magnesium. Both th e rearrange of second ph ase and smaller grain size, which owing to the extrusion process, change the morphologies of corrosion products.

Abstract: The flow of molten metal after being poured usually is accompanied by turbulence, splashing, separation of streams near change of sections, branching off and rejoining of streams, changes in melt properties such as density, viscosity, surface tension and the solidification behavior. In this work, the effect of gating design (ingate thickness) and pouring temperature on the microstructure and fluidity of Al-18% Si alloy into sand mold are investigated. Four different ingates thicknesses of 2.5, 3, 3.5 and 4mm are used. The melt charge was poured at three different pouring temperature (680, 670, 660 °C) into the mold. Decreasing the ingate thickness slightly improves the microstructure to be fine and more globular. Decreasing the ingate thickness increases the hardness of all cast samples. Increasing the pouring temperature increases the filling area of cast Al-18% Si alloy for all ingates thicknesses used in this study. To maintain complete filling for pouring temperatures of 670 °C and 660 °C a minimum of 3.5 and 4 mm ingate thicknesses consequentially should be considered.

Abstract: Casting Mg-Li alloy samples were subjected to annealing and aging treatment respectively, and the corrosion resistance of different samples was investigated by immersion test and electrochemical impedance spectroscopy measurement in 3.5% NaCl solution. The results show that the corrosion resistance of the as-cast sample is the best,the aged sample is the second, and the annealed sample is the worst to resist corrosion.

Abstract: The effect of different tungsten-bearing materials addition in a surface preform, such as Ni-base WC particles, ferrotungsten powders and casting WC particles, on the reinforcement phases at the surface compound layer with a carbon steel substrate is investigated under the condition of vacuum expandable pattern casting V-EPC. The microstructures and reinforcement phases are characterized by optical microscopy, SEM and EDS. Experimental results show that it is impossible to synthesize the independent WC particles in each condition. The tungsten-containing materials are all inclined to decompose during steel infiltration and the released tungsten elements tend to combine with carbon to form fish born-like or strip-like WC or W₂C carbides and dissolve in other type of carbides and matrix.