Metallurgist (v.54, #5-6)

It is shown that factory testing is an effective means of improving thermal and overall efficiency of existing furnaces while reducing the cost of energy and materials. The article examines several methods and types of equipment for real-time diagnosis and monitoring of furnace parameters. Results are presented from factory tests performed on reverberatory, continuous, and bell-type furnaces and recommendations are given to improve their thermal efficiency.
Keywords: factory test; reverberatory furnace; continuous furnace; bell-type furnace

Results from studies of the use of reverse cationic flotation and an effective new reagent-based method for the beneficiation of waste products (Fe ~25% and SiO2 ~54%) formed in processing iron quartzites from the Mihailovskii deposit show that the hematite concentrate which is obtained has an iron content of roughly 60% and contains less than 5% SiO2 (without preliminary dressing). The use of high-gradient magnetic separation for beneficiation of the same waste products yielded iron concentrate with excellent processing properties. It is found that a technology which combines magnetic separation and flotation is the most promising approach to the concentration of materials that contain hematite.
Keywords: iron quartzites; hematite; combination technology; cationic flotation; HGMS

Use of the innovative Romelt technology to process iron-bearing wastes from mines and metallurgical plants by V. A. Romenets; V. S. Valavin; Yu. V. Pokhvisnev; S. A. Makeev; A. I. Gimmelfarb (273-277).
It is proposed that waste products formed at metallurgical plants be recycled by using the Romelt process – a continuous one-stage method of obtaining pig iron from iron-bearing raw materials in a slag bath with the use of abundant inexpensive grades of non-coking coals. Calculations are performed to determine the main economic indices of a project involving the construction of a Romelt facility at an integrated metallurgical plant.
Keywords: technogenic wastes; recycling of wastes; facility design; economic indices; return on investment.

Phase composition and structural features of Severstal Cherepovets metallurgical combine industrial agglomerate by T. Ya. Malysheva; T. V. Detkova; I. V. Loginov; A. V. Gorshkolepova (278-284).
As applied to production and charge conditions of Severstal Cherepovets Metallurgical Combine, the whole production cycle has been studied for industrial agglomerate from the structural features of the granulated charge to the phase composition and mechanical properties of the finished product. x-Ray phase analysis is used to establish the mineral composition of agglomerate silicate binders and their structural formulae are calculated.
Keywords: iron-ore concentrate; limestone; coke fines; recovered material; granulated charge; agglomerate; magnetite; silicate binder; melilite; strength

Study of gallium behavior in blast furnace smelting by P. I. Chernousov; O. V. Golubev; A. L. Petelin (285-290).
Research is performed for determining the gallium content in metallurgical materials of domestic and overseas enterprises. The results demonstrate that gallium passes into iron and it is concentrated in blast furnace slurry. A study of the behavior of gallium in a blast furnace smelting by physical and thermodynamic simulation shows that the increased gallium content of blast furnace slurry is connected with formation under blast furnace smelting conditions of metal sublimate whose source is the organic part of coke. Analysis of physical modelling data makes it possible to suggest development of isomorphous reciprocal substitution of gallium and iron in iron-gallium-aluminum oxide solution, and also formation of metal phase whose composition corresponds to the formula Fe3Ga. The possibility is demonstrated and technology is proposed for obtaining gallium metal from pig iron used as a raw material.
Keywords: blast furnace smelting; gallium; blast furnace slurry; sublimation

Methods which employ atomic-emission analysis and involve microwave and autoclave preparation of samples are developed and are used together with mathematical modeling and factorial experiments to determine the content of platinum-group metals in “low-grade” secondary raw materials that have a hardto-dissolve matrix.
Keywords: certification of secondary raw materials; analytical control methods; platinum-group metals; fireclay wastes from glassmaking; spent autocatalysts; microwave and autoclave decomposition of samples; mathematical modeling and factorial experiments

A new contact-type method is proposed for controlling the cooling of continuous-cast semifinished products in the secondary cooling zone of continuous casters. The method employs water-cooled rollers and a system that controls the flow of coolant water. The method makes it possible to directly measure the removal of heat from the product, and it is based on a series of numerical-analytical models and highly precise algorithms. It is shown that it is possible to computerize control of the quality of cast slabs on the basis of real-time monitoring of the shape of the liquid crater and regulation of the slab’s macrostructure in each section.
Keywords: continuous casting; radial-type continuous casters; secondary cooling zone; controllable crystallization; computer-based control systems

Improving the durability of rolling-mill rolls by S. M. Gorbatyuk; L. V. Sedykh (299-301).
This article examines methods of making rolling-mill rolls composed of hard alloys based on tungsten carbide. A new design is proposed for a compound roll to be used for the rotary rolling of semifinished products made of refractory metals. The roll includes a steel body and a hard-alloy insert. The main operations performed in making the compound rolls are described, and it is shown that they can be effectively used to roll semifinished products made of tungsten-based cermets.
Keywords: rolling mill; refractory metals; hard alloys; powder materials; rotary rolling; technology; design

The experience of world refractory producers indicates that one way of increasing the lining life of melting furnaces is the use of fuzed cast oxide materials. Compositions and the properties of fuzed cast materials based on oxides Al2O3, ZrO2, MgO, and Cr2O3 are provided, that exhibit high physicochemical properties during operation in corrosive media with high temperature loads.
Keywords: oxide; fuzed cast refractory; corundum; escolite; spinel; baddeleyite; corrosion; electric melting furnace

New generation of economically alloyed aluminum alloys by N. A. Belov; V. D. Belov; A. N. Alabin; S. S. Mishurov (311-316).
This article examines the characteristics of a new generation of economically alloyed aluminum alloys developed at the engineering center Innovative Casting Technologies and Materials. Among these alloys: high-strength beryllium-free silumins (AK8ch and Al9Si-Q), ultra-strong nickaline (ATs7NZh), and heatresistant alloys with an addition of zirconium (ALTEK and ATsr1E). It is shown that in aggregate the economic, processing, and service properties of the new alloys are significantly superior to those of their existing commercial counterparts (in particular, alloys AKM3ch, AM4, 5Kd, V96ts-3, and 1201).
Keywords: aluminum alloys; microstructure; processing properties; casting; deformability; nanoparticles of Al3Zr

Innovations in cast magnesium alloys by V. D. Belov; A. V. Koltygin; N. A. Belov; I. V. Plisetskaya (317-321).
This article examines questions related to aspects of the production of castings of magnesium alloys in molds made by volumetric stamping without the use of the corresponding tooling. Information is presented on features of the gating-feeding systems used to obtain magnesium-alloy castings in molds made by volumetric stamping. Also examined are features of the effect of small additions of calcium on the susceptibility of alloys of type ML5 to oxidation during casting in stamped molds. It is shown that the use of calcium in magnesium alloys of the system Mg–Al–Zn is promising for preventing their excessive oxidation.
Keywords: magnesium alloy; Mg–Al–Zn system; volumetric stamping of molds; volumetric stamp; mold; flux-less refining; calcium; Mg–Ca

Effect of cladding on aluminum alloy superplasticity by V. K. Portnoi; A. V. Mikhaylovskaya; M. A. Ryazantseva; S. M. Soloviov (322-327).
The effect of cladding alloy of the system Al–Zn–Mg–Cu–Ni with alloys of different composition on superplasticity indices, and room temperature mechanical properties, before and after plastic deformation, and also overall corrosion and shaping of model components in a superplastic state are studied. It is shown that the best set of indices are for material clad with alloy from the system Al–Mg–Si.
Keywords: aluminum alloy; cladding; superplastic deformation; superplasticity

New generation of solar batteries – hybrid solar batteries with nanoclusters by A. S. Korolchenko; S. A. Legotin; V. N. Murashev; M. N. Orlova (328-331).
An essentially new design and new technology are proposed for making solar cells (SC) that combine the advantages of SC with horizontal and vertical pn junctions. The development and study of hybrid solar batteries make it possible to significantly expand their range of practical uses in solar power generation, especially in space-borne or ground-mounted concentrator systems, laser-based power transmission systems, high-voltage electrical supply systems employed in medicine, and applications in nuclear physics, photometry, and other areas.
Keywords: solar battery; solar cell; hybrid solar battery; hybrid solar cell; SHMC; SC with vertical pn junctions.

The rapid development of gas-based (Midrex, HYL, ENERGIRON) and coal-based (DRyIron, Iron Dynamics, Fastmet, Fastmelt, Itmk3) technologies for the direct production of iron and blast-furnace-less iron metallurgy (COREX, FINEX, Hismelt, ROMELT) in the second half of the 20th Century failed to lessen the dominant role of blast-furnace smelting in extractive iron metallurgy. The blast furnace is expected to maintain this dominance in the 21st Century based on its popularity, economic benefits, and energy advantages. Direct ironmaking technologies that produce a solid metallized product which can be used to make pig iron and steel are also not true alternatives to blast-furnace smelting, but they can play an important role as sources of a clean metallic charge material for electric steelmaking or as processes which can recycle iron-bearing waste products at integrated metallurgical plants. Commercial processes in iron metallurgy that do not employ a blast furnace are inferior to blast-furnace smelting in terms of productivity, the amount of energy consumed, and technical and technological reliability.
Keywords: iron; direction production; metallized product; pig iron; blast-furnace smelting; blast-furnace-less iron metallurgy; energy consumption

Effect of chemical composition and production parameters on nanostructured component formation and a set of properties for high-strength low-alloy structural steels by I. G. Rodionova; A. I. Zaitsev; N. G. Shaposhnikov; I. N. Chirkina; A. M. Pokrovskii; A. A. Nemtinov; P. A. Mishnev; V. V. Kuznetsov (343-352).
The effect of alloying system and production parameters for hot-rolled product and annealing on the mechanical properties of microalloyed steel cold-rolled product are studied. The possibility is demonstrated of a marked effect of the amount and size of MnS particles and nano-precipitates of microalloying element carbonitrides on strengthening by grain refinement and dispersion strengthening. Recommendations are developed for assimilating industrial production of high-strength cold-rolled material with a yield strength of 320–340 MPa.
Keywords: high-strength automobile sheet rolled product; microalloyed steels; alloying systems; production parameters; grain size; nanosize precipitates; mechanical properties; sulfur content; temperature for the end of rolling; annealing temperature

Crystallographic aspects of iron-graphite composite homogenization by T. A. Litvinova; S. N. Egorov; Yu. Yu. Medvedev (353-357).
Diffusion of carbon atoms (ions) in an iron matrix based on crystallography is considered. Structures are determined for a chemisorbed carbon layer and its concentration. The carbon diffusion coefficient in γ-Fe during electrocontact compaction is calculated. The elementary act of C+n movement into neighboring iron octahedral interstices is considered as a basic homogenization mechanism. Intensification of C diffusion in γ-Fe is explained by the effect of an external electric field on the degree of carbon atom ionization in the iron crystal lattice interstices.
Keywords: crystallographic adsorption center; volumetric diffusion; chemisorbed layer; degree of ionization; octahedral interstice

World production of solder alloys is analyzed, in particular in the form of amorphous tapes and powders. The high efficiency of using these materials is noted. Taking account of the variety of metallurgical methods for preparing solders, a single approach is proposed for resolving the task of producing solders: a combination of developing solder preparation technology and their use, i.e., soldering technology.
Keywords: soldering; solder; powder; amorphous alloy; foil.

Effect of friction on the kinematics of metal flow by V. V. Svirin; K. N. Solomonov (362-366).
Kinematic schemes of metal flow are examined for a series of friction coefficients and the dependence of these schemes on the thickness of the semifinished product is evaluated. A comparative analysis is made of the velocity fields in relation to the scheme of metal flow.
Keywords: kinematic scheme; semifinished product; finite-elements method (MFE); virtual experiment

This article is devoted to practical aspects of the introduction of advanced low-waste technologies based on the methods and equipment of vibrational diagnostics as they relate to the operating features and maintenance of rolling milling. The article systematically presents the main factors that preclude the use of traditional approaches in vibrational diagnostics and makes recommendations on negating these factors through the introduction of specially adapted hardware/software systems.
Keywords: vibrational diagnostics; vibration monitoring and diagnosis of rolling mills; stationary vibration-monitoring systems

Studies are made of multicomponent coatings obtained in the system Ti–Al–Cr–Zr–Nb–N by the Arc-PVD method on vacuum-type ion-plasma unit Bulat – NNV 6.6-I1. The coatings were obtained in a medium of reactive gaseous nitrogen. The study results showed that the coatings exhibit high values for hardness and durability when used under continuous cutting conditions.
Keywords: ion-plasma deposition; coatings for lathes; mechanical properties of coatings; hardness and the durability coefficient

Microarc oxidation of light alloys by A. G. Rakoch; I. V. Bardin (378-383).
This article presents some historical background on the invention of the method of the microarc oxidation of materials, its advantages over other methods of forming protective coatings, and the main principles underlying the mechanism of this process.
Keywords: anodizing; microarc oxidation; light alloys; multifunctional coatings

Study of the structure and composition of the bacterial oxidation zone in sulfide minerals by E. V. Adamov; L. N. Krylova; B. L. Egorov; D. Yu. Voronin; V. V. Panin (384-389).
Results are presented from a study of the composition and structure of the bacterial oxidation zone in the sulfide minerals pyrrhotine, sphalerite, and galena in a sulfuric acid solution. The biochemical reactions that occur at the phase boundary are shown. The studies were conducted in the Department of the Beneficiation of Ores of Nonferrous and Rare Metals at the Moscow State Institute of Steel and Alloys. Theoretical studies were also performed and technologies were developed for the bacterial leaching of sulfide ores and concentrates.
Keywords: bioengineering of metals; bacterial oxidation; sulfuric acid; sulfide minerals; pyrrhotine; sphalerite; galena; substitution zone; surface layer; elemental sulfur; phase boundary; reaction; diffusion

This article describes an efficient new method of leaching metals from sulfide concentrates and intermediate beneficiation products with the use of ozone, hydrogen peroxide, and ions of tetravalent iron in a sulfuric-acid solution at atmospheric pressure. Use of the method alleviates the harmful environmental effects of such processing.
Keywords: ozone; hydrogen peroxide; trivalent iron; peroxone; OH-radicals; sulfuric acid; leaching; nonferrous metals; sulfide concentrates; sulfur; mechanical activation; extraction

Development of a reactor-separator flotation machine designed by the Moscow Institute of Steel and Alloys by V. D. Samygin; V. V. Panin; L. O. Filippov; N. Yu. Stenin (394-400).
A new flotation machine of the reactor-separator type has been designed based on the creation of compatible hydrodynamic conditions for control of the main stages of the flotation process in spatially separated zones of the machine. The dependence of the efficiency of the flotation process on the time of residence of the pulp in the reactor is shown to be of an extreme nature and is determined by the ratio of the rates of formation and destruction of flotation complexes and the rate of coalescence of the bubbles. The manner in which the zones in reactor-separators are organized and connected to one another for the selective flotation of mineral particles should be significantly different than for the treatment of waste water. The application of external vibrations (ultrasound) to mineralized air bubbles in the reactor zone makes it possible to independently regulate the process of particle separation and enhances selectivity in the division of copper sulfides from nickel sulfides.
Keywords: reactor-separator; hydrodynamic regime; residence time; rate of separation; ultrasound; selectivity

Characteristics of the superelastic recovery of thermomechanically treated wire composed of alloy Ti–50.7% Ni for use in a stapler employed to reconnect blood vessels by S. D. Prokoshkin; I. Yu. Khmelevskaya; E. P. Ryklina; M. V. Suturin; A. N. Chernov; A. A. Chernavina; M. V. Krasnoshchekov (401-406).
The aortic-coronary shunting procedure developed by Dr. M. V. Suturin with the aid of a unique stapler designed by the company Endogene makes it possible to reconnect blood vessels with staples made of a superelastic Ti–Ni alloy while the heart is still working (without its stoppage). The use of proprietary methods for post-deformation annealing of the wire used to make the staples makes it possible to obtain the best possible functional properties. The difference between the dislocation- and phase-based yield points is Δσ = 900 MPa. The average critical stress associated with superelastic recovery is 1.5–2 times greater after low-temperature thermomechanical treatment than after warm drawing. Fully reversible deformation reaches a maximum of P r1 max = 6.5%, while the maximum force obtained with the staples is P r se = 6.5 N. The high functionality of the staples is proven by the fact that they recover more than 90% of their initial shape. Storage of the staples in the stapler in the straightened state for 1 month has no effect on the degree of shape recovery.
Keywords: functional properties; thermomechanical treatment; stapler; superelastic staples