Metallurgist (v.53, #11-12)
New method of producing pellets from iron-ore concentrate made at the Sokolovsko-Sarbaiskoye mining-concentration combine by S. M. Tleugabulov; A. T. Stepanov; E. E. Kiekbaev; N. V. Chernyi (657-660).
Results are presented from experimental studies performed to obtain pellets from iron-ore concentrate (Fetot = 66.60%). The pellets were obtained with different binders and without binding materials, as well as with the use of different drying and roasting schemes. After metallization roasting, the pellets had a strength on the order of 300–400 kg/pellet. The sulfur content of the metallized pellets is reduced by a factor of 10.
Keywords: iron-ore pellets; strength; molasses binding additive; new technologies; reduction in the production cost of steel
Efficiency of using different types of charging apparatuses on blast furnaces by I. F. Kurunov (661-671).
A comparison is made between the performance indices of blast furnaces with different types of charging apparatuses. It is shown that an apparatus with a rotary charge distributor has several advantages over chute-type apparatuses, including being simpler to install and operate, being more durable, and costing less.
Keywords: blast furnace; charging apparatus; rotary charge distributor; chute-type charging apparatus; evaluation of efficiency
Improving the technology for the tundish refining of steel in order to elevate the quality of continuous-cast semifinished products and rolled plates by O. B. Isaev (672-678).
An integrated technology has been developed for obtaining continuous-cast slabs to be used in rolling plates for critical applications. Special filtration elements are installed in partitions inside the tundish to reduce the content of nonmetallic inclusions in the continuous-cast semifinished product. A channeled ceramic lance for injecting the steel with argon has been developed and installed in the bottom of tundishes to remove nonmetallic inclusions 20 μm or smaller. Metallographic studies confirm the effectiveness of the new technology for obtaining plates of high-strength steels.
Keywords: tundish; nonmetallic inclusions; refining; filtration elements
Study of the hydrodynamics of a 350-ton ladle bath during the treatment of steel on a ladle-furnace unit* by V. P. Piptyuk; V. F. Polyakov; S. E. Samokhvalov; A. B. Kovura; A. A. Travinchev; S. N. Pavlov (679-684).
Results are presented from a numerical study of the hydrodynamic state of a metal bath in a 350-ton-capacity ladle during the injection of argon through bottom lances as part of the metal’s treatment on a ladle-furnace unit. A comparison is made between several variants of treatment, including the use of an injection unit with a single lance, two lances, and an asymmetric three-lance configuration. The hydrodynamics of the bath in the initial period of the injection operation are studied and an evaluation is made of melt flow velocity and the time it takes to establish steady-state flow. Trends in research being performed to develop efficient regimes for the injection of metal in ladles are also discussed.
Keywords: hydrodynamics; metal melt; bottom injection of argon; numerical modeling
Study of the effect of chemical compound composition on a set of mechanical properties and microstructure of sheet rolled product of strength class K65 (X80) by Yu. D. Morozov; A. A. Naumenko (685-692).
Six laboratory melts of low-carbon microalloyed steels were smelted and rolled. The effect of chemical composition and microstructure on steel mechanical properties was analyzed after thermomechanical rolling with accelerated cooling. The optimum microstructure was revealed in order to obtain steel mechanical properties of strength class (category) K65 (X80).
Keywords: chemical composition; controlled rolling; accelerated cooling; microstructure; mechanical properties
Analysis of the electrical regimes of ore-roasting furnaces by V. I. Gusev; V. Ya. Khrolenko; A. L. Sysolyatin; D. V. Kravchenko (693-700).
This article describes the changes that take place in the indices characterizing silicomanganese production for different transformer stages: a decrease in furnace productivity and an increase in unit electric power consumption with a decrease in the secondary winding voltage; a decrease in the resistance of the bath and an increase in the amount of coke in the charge under the same conditions, which determine the amount of manganese recovered. Optimization of the electrical regime entails selecting the regime parameters that correspond to the maxima of useful power.
Keywords: furnace productivity; unit consumption of electric power; voltage stage; resistance; quantity of coke; recovery of manganese; electrical regime; optimization; useful power
Improvement in the efficiency of using ferromanganese in a protective aluminum-containing sheath by G. A. Isaev (701-703).
Some results are presented for a study of an improvement in the efficiency of using ferromanganese due to deposition on the surface of an aluminum-containing film that is a strong deoxidizer. A local zone with a particularly low oxygen content is formed on immersing this material into a melt in an area of manganese dissolution. This makes it possible to increase the degree and stability of ferromanganese assimilation.
Keywords: degree of assimilation; structure; ferromanganese; film thickness; melting; efficiency
Mathematical modeling of the heating of the metal structures of a foundry crane equipped with heat shields by V. G. Popov; Z. K. Kabakov; D. F. Gabtykaev (704-709).
The pouring of pig iron into a basic oxygen converter is accompanied by the ejection of matter from the furnace (incandescent dust-bearing gases, flames, splashing metal, etc.) These emissions act on elements of the casting cranes: the metal structures of the crane, the lifting bogie of the main hoist, the cables, and the cross beam. The effects of high temperatures on the parts of these cranes can be mitigated by using heat shields. A mathematical model was constructed to describe the heating of the surface of the metal structures of a casting crane protected from heat by different methods. Providing the shields with a protective layer of the heat-insulating silica-based ceramic Supersil makes it possible to lower the temperature to which the metal structures of the crane are heated.
Keywords: casting crane; converter; emissions; metal structures; thermal effects; thermocyclic loading; heating process; mathematical model; heat shield; heat-insulating material
Effect of the composition of the raw materials on the strength of sinter made from Mikhailovskii and Lebedinskii concentrates by A. A. Panychev; A. P. Nikonova (713-717).
A study is made of the effect of certain components of the charge used in sintering on the impact strength of the sinter in drum tests. Approximate equations are presented and sintering parameters are optimized: good sinter strength is obtained when the content of trivalent iron in the sinter is 64%, the total content of calcium oxide and magnesium oxide (basic oxides) is 14.3%, the total content of silica and alumina (acidic oxides) is 10.7%, the basicity of the charge is 1.34%, and the content of titanium dioxide in the charge is 0.045%.
Keywords: sinter strength; trivalent iron; calcium oxide; magnesium oxide; silica; alumina; basicity; titanium dioxide
Use of samplers of a new design to sample pig iron by V. P. Gridasov; A. V. Pavlov; S. M. Kovtunets; I. Yu. Komarova; S. N. Pishnograev (718-721).
The blast-furnace shop at the Magnitogorsk Metallurgical Combine has conducted an experiment involving the sampling of conversion pig iron with SA-E samplers made by the company Heraeus Electro-Nite. The new samplers ensure the acquisition of uniform and representative samples. The experiment established the optimum location for sampling the pig iron and the depth to which the sampler should be submerged in the iron. The improvement made in the sampling of pig iron makes the information obtained on the composition of the iron more reliable and reduces the amount of time needed to obtain the sample and prepare it for analysis.
Keywords: samplers; sampling; metal ladle; ingot mold; disk-shaped sample; composition of pig iron
New technologies and equipment in Gipromez projects to improve the quality of steel by B. M. Shapiro; L. M. Savinov; A. M. Nemenov; V. V. Rogozhin (722-727).
In 2007–2008, the company Gipromez developed plans for the construction of ladle-furnace units and steelvacuum-degassing units in the converter shops at the Novolipetsk Metallurgical Combine and the electric steelmaking shop of the Oskolskii Electrometallurgical Combine. Another Gipromez project of interest is the casting-rolling mini-mill being built in the town of Yartsevo (Smolensk Region). In 2008, the company completed a feasibility study of organizing the production of hot-rolled strip at the Lysva Metallurgical Plant in order to provide the plant with its own high-quality starting strip for the subsequent application of corrosion-resistant coatings.
Keywords: out-of-furnace treatment of liquid steel; ladle-furnace unit; steel-vacuum-degassing unit; continuous-casting machine; casting-rolling unit; casting-rolling complex
Conditions for nonmetallic inclusion formation in steels deoxidized with aluminum and calcium by E. A. Chichkarev (728-734).
Results are presented for a study of low-alloy converter steel rolled product contaminated with oxide non-metallic inclusions. Thermodynamic analysis for the conditions of modifying non-metallic inclusions of calcium, and also statistical treatment of experimental data for the effect of different production factors on the contamination of rolled product by non-metallic inclusions are provided.
Keywords: low-alloy steel; modification; calcium; non-metallic inclusions
Properties of low-carbon steels containing bainite in the structure by I. Yu. Pyshmintsev; A. N. Boryakova; M. A. Smirnov; N. V. Dement’eva (735-742).
The properties of low-carbon experimental steels are studied within which a structure of predominantly ferrite-bainite to bainite-martensite is obtained with variation of heating and cooling conditions. The effect of bainite of different morphology on such properties as strength, impact strength and steel deformation capacity is demonstrated. It is established that steels within whose structure there is globular bainite with comparable strength values have a lower ductile-brittle transition temperature than in the presence of acicular bainite.
Keywords: pipe steels; controlled rolling with accelerated cooling; bainite; properties; deformation capacity; cold brittleness threshold
Development of a theory of the rolling of strip with a high-quality shape by E. A. Maksimov (743-748).
This article describes a method of determining the shear strain in the rolling of strip with nonuniform parameters across the strip. It is shown that accounting for shear strain in this case when brass alloys are being rolled makes it possible to refine the mathematical model of the rolling operation in order to more accurately construct the diagram describing the longitudinal component of metal flow velocity across the deformation zone. This diagram characterizes the flatness of rolled strip.
Keywords: planarity; nonuniformity of the rolling parameters across strip; shear strain
Results are presented from a study of the structure of metal at different stages in the fabrication of the bottom of vessels: the tubular forging in the as-received condition; after heating prior to reaming, reaming, normalizing at 910°C, and tempering at 650°C; after forging of the bottom and the corresponding heat treatments.
Keywords: large panels; tubular forging; reaming of tubes; forging of bottoms; heat treatment; structure of metal
Technological advantages of using solid carbon-bearing wastes as an energy source in a conveyor-type pelletizing machine by A. Yu. Feoktistov; V. A. Arsent’ev; I. N. Beloglazov; Yu. V. Sharikov (755-759).
In connection with the need to take steps to save energy and material resources in metallurgy, it is proposed that the industry make use of the energy potential of a new type of fuel that includes carbon-bearing wastes. It is best to use heat from the combustion of such fuel in roasting operations carried out in conveyor-type pyrometallurgical furnaces in order to obtain metallurgical products and by-products.
Keywords: roasting; metallurgy; carbon-bearing wastes; conveyor-type furnace
High-quality wire from electrical-grade bronzes produced by the company kuzotsm by N. S. Arsent’eva; N. F. Bokov; E. A. Kazantsev; L. M. Zheleznyak; L. N. Marushchak; G. V. Beklenishcheva; K. A. Lomakina (760-765).
The chemical compositions of bronzes BrOTs4-3 and BrNKhK are optimized and efficient parameters are found for the deformation and heat treatment of products made of them to ensure that the products have the service properties specified for them. Thermo-mechanical treatments for wire made of bronze BrKhTsrK are studied and put to effective use. All the innovations developed in the course of the research have been awarded Russian Federation patents and are now being successfully used to make commercial batches of electrical-grade wire with excellent physicochemical properties.
Keywords: wire made of electrical-grade tin-zinc; nickel-chromium-silicon; and chromium-zirconium-calcium bronzes; deformation; heat treatment; and thermo-mechanical treatment; excellent service properties
Comparative thermodynamic evaluation of the reactivity of beryllium silicates and lithium silicates to facilitate their processing by V. I. Samoilov; N. A Kulenova; V. I. Zelenin; R. K. Kapasova; A. N. Borsuk (766-770).
Calculations and comparisons of average values of the standard Gibbs free energy for the formation of beryllium silicates are used to expand a known series that orders them by decreasing activity. The series is expanded to also include huegiant, barillite, spherobertrandite, eudidymite, beryllite, and chkalovite: chkalovite > beryllite > eudidymite > danalite > spherobertrandite > genthelvine > helvine > bertrandite > euclase > barillite > phenacite > beryl > huegiant. It is recommended that phenacite and the members to the left of it in the thermodynamically expanded series of silicate be used for direct sulfation, by-passing the expensive decomposition stage. Results obtained from calculation and comparison of average values of the standard Gibbs free energy of lithium silicates are used to construct another thermodynamically substantiated series that orders these minerals in decreasing order of reactivity: kuckite > bickitait > polylitionite > eucryptite > tainiolite = spudomen.
Keywords: beryllium; lithium; reactivity and average Gibbs free energy of formation of the minerals.