At present, Russia is actively developing methods of combined treatment of aluminum alloys, one of which is the method of twin roll casting-extruding. It is very suitable for processing aluminum alloys having a relatively low melting point. The method consists in pouring a melt into the rotating rolls, crystallizing it on the roll surfaces, rolling with a predetermined reduction amount, pressing out in front of the die and squeezing out the product of the predetermined configuration and dimensions through it with drawing ratio in the range of values 10-40. Analysis of technical and economic indicators showed that this method has a number of advantages in comparison with traditional technologies of semicontinuous extruding and continuous casting-rolling. So the output of a good metal at high production volumes can reach 95-97% at a productivity of up to 3-4 tons per hour. In addition, it is possible to quickly move from one profile size to another by changing the matrix. The authors proposed and patented various designs and methods for producing solid and hollow press products from non-ferrous alloys. On their basis, laboratory and pilot-industrial units for combined processing have been created, on which experimental studies have been carried out to obtain long-dimensioned deformed semi-finished products from aluminum alloys series 5xxx, 6xxx, 8xxx and others. The energy-power parameters of the process are determined and found that they are significantly smaller in comparison with traditional technologies (in 10-50 times). Investigations of the mechanical characteristics of press products have been carried out, which showed that when implementing such a treatment scheme, even when producing extruded products from low-plastic alloys, they have a high level of plastic and strength properties. Developed technologies based on the method twin roll casting-extruding now are tested in a laboratory of combined treatment methods in School of Non-ferrous Metals and Material Science in Siberian federal university and industrial conditions of a number of metallurgical plants.
Results of researches of process of hot rolling of ingots from the experimental aluminum alloy which is economically alloyed by scandium are given. The computer model of process of hot rolling with the use of which the straining, temperature and speed processing modes conditions is calculated and also power parameters of processing is calculated in applied to industrial conditions. It is shown that the use in the model of a certain shape of the ingot faces (Petrov's lock) and indirect rolling action in the edging stand is made it possible to reduce the likelihood of the formation and further development of micro cracks on the edges of rolled metal. The adequacy of results of modeling was confirmed by carrying out pilot-industrial tests when rolling large-size ingots from the experimental alloy and obtaining batches of hot-rolled plates and sheets of various sizes. The tensile test was used to study deformed samples after rolling and samples obtained on five regimes of heat treatment with varying heating temperatures of 300, 350 and 380 oС and holding time in the furnace for 1 and 3 hours. The results of the studies on samples of hot-rolled sheets 10 mm thick showed that, compared with the initial state, the strength characteristics of the metal after heat treatment are reduced by an average of 12-20%, and plastic characteristics increase by 50-65%. In this case, the heat treatment regimes 1 - 3 give a good ratio of the ductility and plastic properties of the metal.
The results of a study on the strength of rolled products from aluminium alloys doped with scandium under various processing conditions of hot and cold rolling are presented. The regularities of metal flow and the level of strength of deformed semi-finished products from aluminum-scandium alloys are established, depending on the total degree of deformation and the various modes of single reduction during rolling. It is shown that when using one heating of a cast billet to obtain high-quality semi-finished products, the temperature during the rolling process should not be lower than 350-370°, and the total degree of deformation does not exceed 50-60%. It was found that the semi-finished products from alloys with a content of scandium in the range 0.11-0.12% in the deformed state had elevated values of ultimate tensile strength and yield strength of the metal, which allows them to be recommended for industrial production of sheet metal products.
The structure and properties of cold-rolled strips with a thickness of 3 mm from an experimental aluminum alloy 1580 with a lower scandium content of 0.03% (wt.) relative to the grade of the aluminum alloy and a 5083 similar alloy without scandium were studied. Ingots obtained at the laboratory installation of semi-continuous casting of the Foundry department of the
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