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 semicontinuous casting of the foundry department of the Siberian Federal University (Siberian Federal University, Russia, Krasnoyarsk) were used. The preparation of ingots for rolling included milling up to sizes of 40 × 100 × 145 mm and annealing according to a two-stage mode: at a temperature of 350 °C for 3 h (first stage) and at a temperature of 425 °C for 4 h (second stage). Hot rolling was carried out in the laboratory of the Department of Metal Forming at the Siberian Federal University at a temperature of 450 °C on a two-roll hot rolling mill with a roll diameter of 330 mm and a barrel length of 520 mm to a thickness of 5 mm, which corresponded to a total reduction of 88% with a single reduction of 2–5%. For cold rolling, a two-roll sheet rolling mill with a roll diameter of 200 mm and a barrel length of 400 mm grade LS 400 AUTO was used. Rolling was carried out to a thickness of 3 mm with a single reduction of 2–5%, and then the strip was annealed. The results of determining the mechanical properties by tension by the universal LFM400 machine showed that with an increase in the annealing temperature in the range from 250 to 350 °C for 3 h, ultimate tensile strength of the cold-rolled strips of aluminum alloy 1580 decreases from 385 to 365 MPa. For aluminum alloy 5083, a decrease in this strength characteristic is also observed from 345 to 320 MPa. A decreasing tendency with increasing annealing temperature was also observed for the conditional yield strength
R
p
, and over the entire range of annealing temperatures, the values of
R
p
for strips of alloy 1580 were higher than for alloy 5083 by 35–40 MPa, which amounted to 14–17% The values of the plastic properties, for which the value of the elongation to failure was analyzed, were close throughout the range of annealing temperatures for both alloys. The results of the analysis of micro- and fine structure allowed to conclude that an increase in the strength properties of cold-rolled and annealed sheets from the experimental alloy 1580, compared with alloy 5083, is a consequence of the addition of scandium in the experimental alloy 1580, which leads to an increase in the temperature of recrystallization of the alloy, preserving it contains a subgrain structure and dispersion hardening caused by precipitation of Al
3
(Sc, Zr) phase particles during the decomposition of a solid solution.
The article presents the comparative results of laboratory and industrial studies carried out at Joint Stock Company “Russal Krasnoyarsk Aluminium Smelter” to study the composition and properties of ...cover-refining fluxes FPR-23 and Biomag. The results of the X-ray phase analysis of the studied fluxes were compared, and the particle size distribution of the fluxes on the vibration rotap was determined. The paper presents and describes the experimental scheme and determines the temperature range of melting fluxes. It is shown that, according to the results of industrial tests conducted using the method of a full factor experiment with 2 control factors (temperature and flux consumption), the FPR-23 flux reduces the amount of aluminum in the dross with an increase in temperature and an increase in the specific flux consumption. In addition, the amount of aluminum in the slag when using Biomag flux is practically independent of the melt temperature, although decreasing with increasing flux concentration. The flux FPR-23 has a negligible effect on the Na impurity content in aluminum and reduces the Na content by 0.00004% when the temperature rises to 750°C and the specific flux consumption is up to 1.5 kg/t. At the same time, the use of Biomag flux does not contribute to the reduction of Na in the metal melt. The content of the Ca impurity in the aluminum melt is not affected by the FPR-23 flux. The use of Biomag flux reduces the Ca content in an aluminum melt by an average of 0.000085%. The article shows that the use of FPR-23 flux does not reduce the concentration of hydrogen in an aluminum melt, while the use of Biomag flux reduces the concentration of hydrogen in an aluminum melt by an average of 0.02 cm
3
/100 g Al.
The main disadvantage of the existing sampling method of metal for hydrogen content analysis is the contact of metal with air moisture during an open overpour from a metal scoop to the ingot mold. In ...response, a novel method is proposed for sampling molten aluminum and its alloys for hydrogen content analysis by dipping a conical ingot mold sampler into the melt. The work was performed at the Sayanogorsk aluminum plant UC RUSAL in the technological workflow from a transport ladle to the casting machine. Hydrogen analysis results using the proposed method are compared to those of the sampling method using the Rensley chill mold. The error in the hydrogen content measurement of the sample under the existing sampling scheme with overpour of metal from a metal scoop into the ingot mold was confirmed. The hydrogen concentration in the samples taken in the Rensley chill mold is less, on average, by 0.019 cm
3
/100 g Al, than in the samples obtained using the newly developed ingot mold sampler. Results of the study reveal that the proposed sampling method provides an additional advantage when sampling molten metal.
Al–3Ti–1B and Al–5Ti–1B master alloys represent the most popular modifiers for the majority of aluminum alloy groups. To date, several methods, requiring various conditions and resource costs, have ...been applied for producing these master alloys. The paper presents the results of a comparative analysis of methods for producing Al–3Ti–1B master alloy using both a Ti sponge and salts (K
2
TiF
6
and KBF
4
) as the starting components. The degree of Ti and B recovery for three methods of the master alloy production was experimentally established. The phase and element compositions of slags were studied; the amount of fluorine gas, emitted during the master alloy production, was calculated. A method, using a titanium sponge and molten KBF
4
+ KCl mixture, was identified to ensure a recovery of Ti and B equal to 88.10 and 72.20%, respectively. The modifying ability of the produced master alloys was studied both according to the TP-1 method and using the laboratory and industrial unit of semi-continuous casting.
The results of experimental studies on the development of a method for obtaining titanium-containing bar ligature, the study of its structure and modifying ability are presented. The distinctive ...features of the new technology are the use of titanium sponge and/or titanium shavings as titanium raw materials, the primary alloying of aluminum with titanium, and then boron, the introduction of titanium in two stages: initially, 2/3 of the titanium metal raw materials are dissolved in the aluminum melt, and the remaining amount is introduced after the reduction of potassium tetrafluoroborate. Pre-impregnation of the titanium sponge with halide-containing flux and the use of a briquetted mixture of KBF
4
+ Al-powder are also provided. The experimental technology for the preparation of the Al–Ti–B melt is described, the extraction of titanium and boron into the ligature is calculated, its microstructure is investigated, and the chemical and molecular compositions of the resulting slags are determined. Deformation treatment for the production of bar ligature was carried out by the method of direct extrolling which made it possible to level the defects of the cast structure. It is established that the use of high-speed crystallization-deformation in the implementation of the combined direct extrolling process makes it possible to obtain alloying bars of a given diameter at minimal energy consumption with the required complex of mechanical and operational properties. A quantitative assessment of the modifying ability of the experimental cast-iron ligature and the deformed cast-iron rod obtained by the direct extrolling method was carried out in comparison with the mass-produced cast-iron ligature produced by KBM Affilips (the Netherlands/Belgium). Based on theoretical and experimental studies, the composition and technology for producing Al–Ti–B modifying ligature using titanium sponge and/or shavings and potassium tetrafluoroborate with a content of 3.0 ± 0.3% titanium and 1.0 ± 0.2% boron as alloying additives have been developed, which meets the requirements for the composition of aluminum ligatures.
Aluminium alloys containing small additions of scandium exhibit unique operating properties. Alloying material with scandium significantly improves product weldability, reduces the tendency towards ...hot cracks and improves welded joint mechanical properties. The aim of this work is to increase the scandium extraction into a master alloy by preliminary transformation of scandium oxide into fluoride and introduction into the composition of an aluminium powder alloying additive. Results are provided of laboratory experiments for preparation of aluminium-scandium master alloy by aluminothermic reduction of scandium fluoride using sodium fluoride and aluminium powder within the alloy composition. Scandium fluoride is prepared by treating scandium oxide with 40% hydrofluoric acid. The overall extraction of scandium from oxide into fluoride and from fluoride to the aluminium-scandium master alloy is 88.5% with an average scandium concentration in the master alloy of 1.90 wt.%. The microstructure of the master alloy obtained is represented by scandium aluminide Al
3
Sc crystals with a size from 10 to 25 μm uniformly distributed within the master alloy. An additional reserve for increasing the extraction of scandium into the master alloy and reducing its cost is processing of slags formed in the preparation of the ligature. The use of an aluminium powder with high specific surface area in the composition of the alloying additive increases scandium extraction into the master alloy due to better contact of the reacting phases. The resultant Al–Sc master alloy has uniform distribution of Al
3
Sc particles within the volume of the metal.
The γ n → π 0 n differential cross section evaluated for 27 energy bins span the photon-energy range 290– 813 MeV (W = 1.195–1.553 GeV) and the pion c.m. polar production angles, ranging from 18° to ...162°, making use of model-dependent nuclear corrections to extract π0 production data on the neutron from measurements on the deuteron target. Additionally, the total photoabsorption cross section was measured. The tagged photon beam produced by the 883 MeV electron beam of the Mainz Microtron MAMI was used for the π0-meson production. Our accumulation of 3.6 × 106 γ n → π 0 n events allowed a detailed study of the reaction dynamics. Our data are in reasonable agreement with previous A2 measurements and extend them to lower energies. The data are compared with predictions of previous SAID, MAID, and BnGa partial-wave analyses and to the latest SAID fit MA19 that included our data. Selected photon-decay amplitudes N * → γ n at the resonance poles are determined for the first time.
Results are given for research aimed at improving the quality of large tonnage flat ingots under RUSAL Joint Company (Krasnoyarsk) conditions as a result of reducing the hydrogen content within them ...to less than 0.1 cm
3
/100g. For this purpose, under production conditions the change in molten aluminum alloys series 1XXX hydrogen content is analyzed in the main stages from the aluminum electrolyzer to the casting machine. Production operations are determined within which there is significant melt impregnation with hydrogen. Research precision is provided by using a developed procedure for molten sample collection in the main production operations and considering the specific nature of production. Technical solutions are proposed from research results aimed at reducing melt hydrogen expansion.
The article describes the characteristics of electrolytic carbon foam of aluminum production and analyzes the impact of recent changes in the technology of aluminum production on the structure of ...formation, composition and properties of fluorocarbon-containing wastes, reviews the currently proposed methods for their processing, substantiates the feasibility of large-scale waste processing in related industries. The paper evaluates the method of processing finely dispersed fluorocarbon-containing wastes of aluminum production using the example of a model type of raw material (pure cryolite and chiolite) and coal foam by lime milk caustification to obtain a product containing synthetic fluorite. A thermodynamic calculation was carried out and a mechanism for the causticization of wastes containing chiolite and cryolite was proposed. It is shown that when interacting with lime waste containing cryolite and chiolite, in addition to calcium fluoride, a solution of sodium aluminate is formed, which, depending on the concentration of alkali in the solution, can be supersaturated in aluminum hydroxide or sodium hydroxide. The influence of technological parameters (temperature, process time, dilution) on the completeness of causticization of raw materials is determined. Caustification of model raw materials is determined that the main influence on the efficiency of its flow is provided by the temperature of the process, which is associated with a high fluorine content in the raw material. When coal foam is caustified in the range of 60-80 °C, the temperature change does not affect the process and the CaF2 yield reaches almost 800 kg per 1 t of feedstock.
PDF
