Том 59, № 9-10 (2016)

The main problems encountered in the remote monitoring of energy use in metals production and other industries are identified. Such monitoring entails long-term observation of energy parameters along with production data, in addition to vectorial representation of the criteria chosen to assess energy use. A new approach is proposed to the synthesis of a web-oriented system based on theoretical-multivariate, parametric, and structural modeling of remote energy monitoring. The structure of the system is detailed by employing a modular multipurpose hardware-software complex that includes open interfaces, the original source code, and licenses for free dissemination of the software. Results are presented from the practical use of specialized elements of the remote energy monitoring system and the synthesized structure in accordance with the above-described approach. Also, a method is proposed for evaluating the effectiveness of the monitoring systems that are created.

Actual temperatures of structural and phase transformations Ar₃ and Ar₁ for different chemical compositions of low-alloy pipe steels are determined on the basis of dilatometric studies. Equations are obtained for calculating the temperature of critical points Ar₃ and Ar₁ taking account of the effect of 14 main chemical elements as a result of processing experimental data. It is shown that Ar₃ and Ar₁ temperatures calculated by well-known equations differ (by 10–80°C) considerably from actual temperatures, whereas the relationships proposed increase the precision of critical temperature calculation for low-alloy steels by 10°C at least.

The effect of low-alloy steel type X70-X80 composition and thermomechanical treatment (TMT) parameters on the main processes of austenite structure formation and final intergranular ferrite-bainite structure, and also sheet and coiled rolled product properties are studied. A favorable effect is demonstrated for an increase in Nb content in steel (up to 0.09–0.10%) in limiting grain growth and a shift in the temperature range for austenite partial recrystallization (T₉₅–T₅) into a higher temperature region. Rolling in the partial recrystallization range causes formation of a varied grain structure containing extended areas of lath bainitic ferrite, as a result of which there is a reduction in low-temperature toughness and cold resistance. The effect of adding Mo, Ni, Cr, and Cu on the nature of steel X70 phase transformations is provided. Different types of Nb(C, N) and (Nb, V)(C, N) particle precipitates within austenite and ferrite are shown. Results are summarized for previous studies.

The design of a Ø120-mm piercing mandrel is optimized for use on a two-high rotary rolling mill with mushroom-shaped rolls and Diescher guide discs. A numerical model of the piercing operation is constructed as well.

The nature of change in the amount and morphology of iron dendrites and excess phases in relation to the degree of high-carbon alloy melt supercooling is considered. It is revealed that in pure iron-carbon alloys by changing the degree of melt supercooling it is possible to obtain steel with a carbon content as in white cast iron, or white cast iron with a carbon content as in steel. It is shown that before forging Damascus steel the structure is ideal with a pearlite matrix, without secondary free cementite, and with excess ledeburite phase. Features of ferrite and ledeburite shape change with thermomechanical treatment (forging) are studied. It is detected that during deformation heating for forging there is ledeburite recrystallization into a more stable phase of eutectic carbide. Limits are determined for transformation of pure high-carbon alloys in carbide class steel of the Damascus type.

Modification of a titanium surface layer with yttrium is performed by a combined method providing electroexplosive alloying and subsequent treatment by a high-intensity electron beam. Alloyed layer elemental and phase composition, defect substructure, mechanical and tribological properties are determined. Saturation of a titanium surface layer with atoms of yttrium, oxygen, and carbon is revealed, which leads to the formation of a cermet layer strengthened with titanium and yttrium oxides and carbides and facilitates a multi-fold increase in microhardness and a reduction in modified layer friction coefficient and wear rate.

Copper-phosphorus solders in the form of ribbons with a phosphorus content of 5–8%, thickness of 0.2–1 mm, and width of 10–20 mm are widely used to secure windings and contacts in electrical machinery. Certain alloys which are based on the copper–phosphorus system and contain a nickel addition are made in the form of ribbons that are in the amorphous state and are less than 100 μm thick. They are used to solder copper alloys in high-precision assembly work. Since the processing properties of copper-phosphorus solders are usually equivalent to those of solders that contain silver, they are used in place of silver-bearing solders as long as the finished joints have the required service characteristics. One serious drawback of copper-phosphorus solders is the difficulty in shaping them, which is due to the presence of brittle copper phosphide in the structure (this phosphide can account for up to 50% of the volume of the solder in some cases). Some factories fill their own needs for solder by turning heated cylindrical ingots on a lathe to make chip-shaped ribbons thinner than 1 mm. Such a technology is obviously unsuited for industrial use. Thus, in international practice copper-phosphorus alloys are made either by hot deformation or by casting a melt on a rotating mold. To more thoroughly investigate copper-phosphorus solders and the entire process of making them by feeding a melt laterally onto a rotating roller mold, tests were performed with the use of different speeds of rotation of the mold. The speed of the mold affects the geometric parameters and structure of ribbons based on alloy PMF7. The results of the tests are reported in this article.

The Seventh International Conference “Aluminum: Alloys, Rolled Products, and Profiles for Industry and Construction” was held in Samara on May 28–29 of this year. The conference was organized by the journal “Metallosnabzhenie i Sbyt” with the help of the Russian Association of Metal-Product Suppliers (RSPM), Metal-Expo, and Alcoa Russia. Among the participants were more than 100 directors and specialists from companies that make various types of aluminum products, metals traders, public organizations, and other entities.

Strength calculations are performed for a new part with allowance for the forming operations used to make it. The process of accounting for the technological history of the part in such calculations is illustrated by examining the strength design of a part in the form of a branch pipe composed of two and/or three smaller parts with welds.

There are many large fans currently in use in different sectors of industry, and replacing them at the end of their service life is an important issue. Most existing fans are made of metals, but plans are in place to replace them with fans made of composites. The use of new materials and the design of fan blades with new shapes will make it possible to reduce the weight of the structure, thus also reducing energy costs and making the operation of cooling towers more efficient. The development and introduction of new fan materials and designs can be aided by the use high-performance computer systems and advanced software programs.

The meta-dynamic recrystallization behavior of SCM435 steel was studied on the MMS-200 thermal simulation machine through the double-pass compression experiment. The effects of the deformation temperature, the strain rate, and the initial austenite grain size on meta-dynamic recrystallization were analyzed. Based on the test result, the kinetics model of the meta-dynamic recrystallization of SCM435 steel was established, and the obtained activation energy was 242.3kJ/mol. The results showed that the meta-dynamic recrystallization fraction X_m of SCM435 steel increased as the deformation temperature and the deformation rate increased, decreased as the initial grain size increased, and increased as the time interval increased.

Chromium corrosion-resistant steels alloyed with nitrogen are studied by experiment. It is shown that depending on chemical composition and production parameters the steel’s structure may be martensitic with a minimum residual austenite content, martensitic with a higher residual austenite content, or threephase consisting of martensite, residual austenite, and ferrite. The possibility is demonstrated of residual austenite transformation into martensite during cooling after tempering at 400°C, which leads to an increase in steel hardness and correspondingly strength.

Features of nonmetallic inclusion formation and evolution in the course of treating spring steel of 54SiCr6 (60S2KhA) grade are studied. It is established that the majority of nonmetallic inclusions (NI) present within steel are complex oxides of the composition SiO₂–MnO–Al₂O₃–CaO–MgO, at whose surface during steel crystallization and cooling as a rule there is a deposit of MnS. NI composition changes in the course of metal treatment. At the start of treatment, their base is MnO–SiO₂–Al₂O₃, and subsequently there is an increase in content of CaO and MgO as a result of molten metal reaction with slag and lining. The average NI size and overall oxygen content decrease in the course of steel treatment, and this points to effective refining. The composition of NI present is close to that of the slag cover assimilating layer used in the intermediate ladle. A more significant increase is noted in MgO and Al₂O₃ content within it, and this points to effective assimilation of NI of the most unfavorable types.

In order to establish the scientific principles of a technology for the production and ladle treatment of new steels that can be quenched at forming, steels which were made in factory and laboratory heats and had different carbon contents were analyzed to explore the key factors and processes that determine both their total content of nonmetallic inclusions (NIs) and their content of certain types of NIs – particularly the types that are harmful. It was found that the most important factors in producing steel which is clean based on its content of all types of inclusions (which has an NI rating no higher than 1.5 in the government standard GOST 1778) are the slag regime and the ratio of the weights of the lime and aluminum added to the steel-pouring ladle during tapping. The optimum ranges of values for these parameters are determined. The existing requirements on the slag-regime parameters are observed to ensure a low content of harmful corrosion-active nonmetallic inclusions (CANIs) in the steel. However, it is essential to maintain a low (at or below the lower limit of 0.02% specified for the grade of steel) aluminum content for the duration of the ladle treatment. Aluminum content can be increased during the final stages, if necessary. A study was made of the effect of the MgO content of the covering slag on the possibility and rate of formation of CANIs based on alumomagnesian spinel. it was found that the steel’s content of such inclusions rises sharply when the concentration of MgO in the covering slag is greater than 14.1%. An MgO content of up to 8% guarantees that the steel will be clean based on its content of all types of inclusions. The results obtained for the metal of two trial heats confirmed the adequacy of the key parameters that were identified and the ranges of values for those parameters which were determined to be optimum for obtaining a low CANI content and high resistance to local corrosion.

A new microprocessor-based system for monitoring rolling forces has been designed and built, the system making it possible to measure and record changes in the load on the rolls along sheet that is in the process of being rolled. Introduction of the monitoring system was the second stage in the modernization of the two high 150×235 mill in the laboratory of the Metal-Shaping Machines and Technologies Department at MAMI. The mill was then used to perform an experiment that made it possible to evaluate the effect of the draft and the contact-friction conditions on the deformational and force parameters in the rolling of copper sheet. The experimental results also confirmed the utility of the force-monitoring system that was developed.

This article is devoted to the leaching of gold from copper-bearing oxidized stubborn gold ores in the Tarror deposit. The high copper content of the ores makes it difficult to extract gold from them by direct cyanidation. An analysis of the literature data indicated that ammoniacal leaching might be one solution to this problem. It is shown that the use of ammonia compounds in the cyanidation cycle makes it possible to obtain high indices for gold recovery without the accumulation of complex copper compounds in the solution. The amount of cyanide consumed in the production process is reduced accordingly.

This articles examines the formation of high-quality joints between aluminum bronzes and copper-nickel alloys that contain different amounts of nickel. The joints are formed by explosion welding or hard-facing as part of the fabrication of products for chemicals production, gas engineering, shipbuilding, and other sectors of industry (reinforcement bars, heat exchangers, pipelines, etc.). A study is made of the effect of the nickel content of copper-nickel welding wires on crack formation in hard-faced metal, its structure, and its mechanical properties when aluminum-nickel bronze of grade Br.A9Zh4N4Mts1 is joined with copper-nickel alloys by argon-arc welding and hard facing. It is shown that the use of welding wires made of copper-nickel alloys with a nickel content of up to 18% guarantees the formation of high-quality crack-free joints with mechanical properties that are comparable to the properties of the lower-strength material which is used.

A novel tundish refining technology has been developed for the production of complex alloying corrosionresistant steel plates made from continuously cast slabs. This technology includes application of filtering elements installed in the tundish buffers to provide a decrease in the nonmetallic inclusion content in the slab body. It also makes use of injection-vertical shrouding of the steel in the area of steel ladle-tundish for the reduction of oxygen and nitrogen content in the steel and for the reduction of aluminum consumption. Argon rinsing of liquid steel in the tundish through ceramic bottom lances with a modern design is proposed for the removal of fi ne inclusions (≤20 μm). There was an overall decrease of the tested steel contamination by 2.0–2.5 times, and the amount of sulfide inclusions decreased, on an average, by 65%, oxide inclusions by 40%, and nitride inclusions by 60%. Hydrogen removal reached up to 0.3–0.8 ppm. Comprehensive metallographic examinations confirmed the efficiency of the novel tundish refining process and the high yield of high-performance rolled plates.