Volume 46, Nº 12 (2016)

In Ni–Cu alloys, iron must be excluded in many cases. Iron may enter the alloy from the batch or the furnace lining. Since the Fe₂O₃ content in refractories may be as much as 2.5%, it is important to assess the increase in iron content in alloys on account of interaction with the furnace lining. In the present work, the influence of the Fe₂O₃ content in the crucible and the volume of the crucible on the iron content in the final alloy is studied. Thermodynamic analysis and experimental data indicate that the nickel and copper in Ni–Cu alloys may reduce iron that is present in the lining. When using low-iron batch, iron from the crucible is transferred almost completely to the melt. The increase in iron content in Ni–Cu alloys is investigated as a function of the capacity of the vacuum induction furnace and the Fe₂O₃ content in the periclase crucibles, with complete transfer of the iron from the lining to the melt. With increase in furnace capacity, less iron enters the melt from the crucible. With more than 200 kg of metal, the increase in iron concentration mainly depends not on the furnace capacity but on the Fe₂O₃ content in the refractory. In order to produce Ni–Cu alloys with <0.01% Fe, refractories with Fe₂O₃ content no higher than 0.5% must be used. To produce Ni‒Cu alloys with <0.05% Fe, the use of lining refractories with Fe₂O₃ content no higher than 2.5% is recommended.

The use of pulverized coal in Russian blast furnaces is analyzed. It is shown that the rates of pulverized- coal injection are considerably less than for the world’s best furnaces. The factors hindering such developments in Russia are presented. Measures intended to reduce carbon-dioxide emissions in hot-metal production (the ULCOS program) are analyzed. The introduction of multifuel gas generators of bubbling type in blast-furnace shops is proposed. The hot reducing gases produced in this system will then be injected in the blast furnaces. The operational parameters of a 1033-m³ blast furnace with the injection of hot reducing gases at rates up to 400 m³/t of hot metal are calculated. The injection of hot reducing gases at a rate of 400 m³/t would save coke at a rate of 100–120 kg/t of hot metal. With gas injection at a rate of 700 m³/t, the expected coke savings are as much as 200 kg/t of hot metal. The creation of a consortium of leading steelmakers to develop this technology to the point of industrial trials is recommended.

The localization of plastic strain in the extension of 08ps low-carbon steel is compared after hot rolling and after electrolytic saturation with hydrogen by means of a three-electrode electrochemical cell. Analysis of the strain curves shows that they include a plasticity region, a stage of linear strain hardening, and a stage of parabolic strain hardening (Taylor hardening). Double-exposure speckle photography is used to visualize the localized strain zones. On that basis, the quantitative deformation characteristics may be obtained. In other words, the displacement-vector field in a plane sample under extension may be determined, and then the components of the plastic distortion tensor (the local elongation ε_xx, shear ε_xy, and rotation ω_z) may be calculated. The basic types of plastic flow localization are identified at different stages of strain hardening, and their parameters are determined.

A production technology for iron-ore materials with improved metallurgical characteristics is developed and tested. The following materials are considered: fluxed pellets containing residual carbon; fluxed local agglomerates from concentrates with a wide range of silica content; local agglomerates with an elevated iron content; local agglomerates with residual carbon; and local agglomerates with both elevated iron content and residual carbon.

Considerable time is required for industrial tests to assess the utility of quartz and quartzites in the production of silicon ferroalloys. A relatively simple method of classifying quartzite with respect to the production of silicon, ferroalloys, carborundum, and carborundum-bearing reducing agents has been devised on theoretical principles and introduced in practice. This method is based on measuring the degree of gasification of quartzites from a mixture with carbon reducing agents whose composition is calculated so as to ensure stoichiometry of the reaction SiO_2s + C_s = SiO_v↑ + CO_g↑.

The alloying of steel resistant to atmospheric corrosion is discussed. The differences and similarities of the Russian GOST, European EN, and United States ASTM standards regarding the chemical composition of such steel are analyzed. The prospects for the production of corrosion-resistant high-strength steel sheet exceeding the requirements in the EN 10025-5 standard are considered. In trials, the possibility of producing steel sheet with elevated low-temperature impact strength is demonstrated. Production technology for high-strength steel resistant to atmospheric corrosion is developed.