Metallurgist (v.62, #1-2)

Analysis of Wastewater by ICP-MS by P. V. Yakimovich; A. V. Alekseev (3-9).
Modern high-temperature nickel alloys used in the aviation industry and engine building are doped with different elements to the maximum and thus have a complex chemical composition. Production of these alloys can result in contamination with wastewater dumped into centralized sewerage system. Therefore, an important task is to control the chemical composition of wastewater produced at industrial enterprises. In this work, the contents of aluminum, phosphorus, sulfur, chlorine, chromium, manganese, iron, nickel, copper, zinc, arsenic, cadmium, lead, and mercury in wastewater samples were determined by inductively coupled plasma mass spectrometry (ICP-MS). The technique of dissolving the sample and preparing it for analysis is given. Spectral interference was addressed using a reaction-collision cell and a mathematical correction. The range of determined concentrations was 0.0001–50 mg/dm3, the relative standard deviation did not exceed 20%.
Keywords: inductively coupled plasma mass spectrometry; ICP-MS; wastewater analysis; microwave sample preparation; mercury determination

We describe a design concept for a data analysis system to support process automation for comprehensive management of the production process and economic performance of a metallurgical company, and for making automated technical and economic performance decisions. This topic has been widely discussed in the worldwide scientific literature, but the potential risks of automating the decision-making process have received scant attention. Certain applied problems will require development of procedures supported by a cost-benefit analysis of the automation tools.
Keywords: mathematical modeling; information systems; technical-economic analysis; business management metallurgy

Predictive Mathematical Model of the Process of Metal Heating in Walking-Beam Furnaces by S. I. Ginkul; A. B. Biryukov; A. A. Ivanova; P. A. Gnitiev (15-21).
We propose a mathematical model for the analysis of the temperature distribution in the cross-section of billets heated in walking-beam furnaces and the determination of rational lengths of the zones of the furnace in the design stage. The influence of the size of the gap between the billets on the dynamics of their heating is investigated. We determine parameters affecting the output of the furnace and the volumes of fuel consumed for heating.
Keywords: walking-beam furnace; process of heating; temperature field; mathematical model

We discuss various issues involved in processing of ferrous metallurgical waste, specifi cally blast-furnace and converter waste, using the ArcelorMittal Temirtau experience as an example. We study the methods currently used for disposition of these materials by the company and by the ferrous metallurgy industry as a whole, as well as potential reprocessing methods proposed by researchers in the CIS and other foreign countries. The analysis performed here indicates that blast-furnace slag is appropriate for use as a material in sub-bases for roads. We propose a method for improving the physical and mechanical characteristics of blast-furnace slag, including filling the pores in the slag with a cement/microsilica mixture and making the slag water-repellent with used motor oil. We describe the results of experimental studies performed on the resulting material. Given that the company produces 600,000 metric tons of blast furnace slag per year, using this approach for complete reprocessing and subsequent sale of the slag will reduce the production costs for ArcelorMittal Temirtau end products by 1.725 million US dollars per year, provide an alternative raw material for users, reduce environmental impacts, and conserve natural resources.
Keywords: metallurgical industry waste; industrial waste; blast furnace slag processing; ArcelorMittal Temirtau; ecology; physical-mechanical properties

Complex Loosening of Lepidolite Concentrate by Sulfuric Acid by V. I. Samoilov; Zh. S. Onalbaeva; М. А. Adylkanova; G. А. Kokaeva; S. А. Abdulina (29-33).
Experimental study of complex extraction of lithium and other valuable components from lithia mica – lepidolite was carried out. A method of complex processing of lepidolite is suggested in the present work, that provides extraction of such valuable components as lithium, potassium, cesium, rubidium, aluminum, and beryllium from this mineral. Moreover, energy consumption was minimal during this process. Results of the research set up preconditions for large-scale involvement of lepidolite in the hydrometallurgy of lithium, given the large number of proven deposits of lepidolite and the ever-growing demand for lithium products in different countries.
Keywords: lithium; lepidolite; sulphuric acid; complex loosening; hydrometallurgy

We present the results of investigation of the influence of boron-containing admixtures on the physical properties (viscosity and melting point) and the desulfurizing ability of ladle slags in the process of treatment of steel in ladle–furnace facilities. It is shown that the introduction of В2О3 in amounts of up to 4% in high-basic high-alumina slags significantly extends the range of their homogeneous liquid state and guarantees a high degree of desulfurization and microalloying of the metal with boron (0.001–0.004%).
Keywords: steel; ladle refining; boron-containing slags; microalloying

Formation of Transverse Surface Cracks During Peritectic Steel Continuous Casting by A. V. Fedosov; A. M. Skrebtsov; D. V. Pashchuk (39-48).
Various mechanisms of transverse crack formation within the surface of continuously-cast billets in the pouring temperature range are analyzed. It is shown that low mechanical properties of peritectic steels in the high-temperature region are due to the high temperature for completion of the δ→γ transformation (Tγ). The effect is considered individually of grain size on metal mechanical properties. Conditions are analyzed for the formation of coarse grains during continuous casting of peritectic steels. It is shown that in the low-temperature region key effects are stress concentration conditions at grain boundaries and intergranular bond forces. On the basis of this analysis, a series of recommendations is proposed for reducing the probability of forming surface cracks in billets.
Keywords: continuous casting; peritectic steel; surface crack; grain boundary; relative elongation nonmetallic inclusions

Research is conducted within the scope of the Clean Steel project into reasons for variation of the metal level in a crystallizer and breakouts of the crystallizing metal skin in a thin-slab CCM, and also a study of reasons for defect formation in hot-rolled strip. Examples are provided of improved monitoring and control of the VMZ casting and rolling complex (CRC) technology. Implementation of the monitoring production technology – evaluation of metal product quality – operational adjustment of technology concept makes it possible to reduce the CCM emergency situation index to less than 0.5 ton/105 tons of steel, and also to determine factors influencing the formation of transverse cracks over a rolling mark, and to remove defect formation.
Keywords: monitoring and control of electric steelmaking workshop technology; casting and rolling complex (CRC); pipe steels; clean steel; breakouts of crystallizing metal skin in thin-slab CCM; hydrogen; hot-rolled strip surface defects

The NLMK’s Experience of Operating Slab CCM Molds with Improved Wall Design by S. V. Filatov; A. I. Dagman; V. N. Karavaev; V. P. Glebov; G. N. Kononykhin; A. B. Kotel’nikov; A. A. Vopneruk (58-61).
NLMK’s experience in operating the continuous casting machine (in steel shop 1) with a mold with multi-taper working surfaces and wear-resistant thermal-spray coating is described. The changes to the design of the working surfaces that contribute to the formation of slab crust of uniform thickness are described.
Keywords: mold; multi-taper slab; CCM

Testing Baked Anodes with an Increased Vanadium Content by E. S. Gorlanov; A. A. Batrachenko; B. Sh.-A. Smailov; A. P. Skvortsov (62-69).
Results are given for testing baked anodes for aluminum electrolyzers prepared from high-sulfur petroleum coke. In anodes of these cokes, there is an increase in vanadium content to 600 ppm that contaminates aluminum. By boriding aluminum, the possibility is established of using high-sulfur petroleum coke with a high heavy-metal content in production. It is shown that introduction of micro-additions of boron into molten electrolyte and aluminum makes it possible to reduce the vanadium content in metal from 200–220 to 100–120 ppm. The production regime in test electrolyzers remained stable for the test period. An associated effect of boriding melts is a fixed reduction in voltage loss in the cathode by about 30 mV that corresponds to a reduction in electrical energy of about 1700 US$ per year per electrolyzer (with a price of 0.02 US$/kW·h).
Keywords: high-sulfur coke; vanadium; melt boriding aluminum boride suspension; wetted cathode

Multicycle Fatigue of Single Crystal Nickel Superalloy by M. S. Belyaev; M. R. Orlov (70-77).
Multicycle fatigue of an experimental low-alloy single-crystal nickel-base superalloy is studied in relation to crystal orientation and test temperature. It is established that with an increase in test temperature from 20 to 900°C a change is observed in the shape of the multicycle fatigue curve. Scanning electron microscopy is used to determine the nature of fatigue failure. The work was conducted within the scope of a priority area for development of RF science, technology, and engineering, i.e., transport and space systems.
Keywords: single crystal nickel-base superalloy; crystallographic orientation; multicycle fatigue; fractographic analysis; scanning electron microscopy

Rich Zinc Phase Formation Mechanism at the Surface of Continuously-Cast Brass Billets by S. A. Tavolzhanskii; V. E. Bazhenov; I. N. Pashkov; E. S. Ivanov (78-83).
This work is devoted to studying formation of a rich zinc phase at the surface of continuously-cast brass billets. It is shown that the effect almost always occurs during brass continuous casting. A study of rich zinc phase formation is performed for small section ingots prepared by continuous casting vertically upwards. Microstructural analysis is conducted for sections of ingots in zones of rich zinc phase formation and its composition is determined. A mechanism is proposed for the formation of this phase including zinc sublimation and condensation in the shrinkage gap followed by spreading zinc over the ingot surface and partial dissolution within it of basic composition alloy. Methods are analyzed and proposed for minimizing this phenomenon under brass ingot continuous casting conditions.
Keywords: continuous casting; brass ingot; copper-zinc solder; graphite crystallizer; sublimation; condensation

In dissimilar welded joints, data for the phase composition of the fusion zone may be taken from the phase equilibrium diagram composed in the course of experimental observation of phases. Results are given in the article for test laser welding of low-carbon steel plates, clad with austenitic stainless steel, and specimens are studied demonstrating perfection of the welded section austenitic microstructure. This confirms the data about the reliability of martensite-austenite boundaries studied by D. T. Kotecki on the example of chromiumnickel deposits prepared by submerged arc welding on carbon steel plates. Welds are studied by optical and scanning electron microscopy, and microhardness is determined by the Vickers method. The content of the main substitution alloying elements is calculated by means of energy-dispersion spectroscopy. The nitrogen content is determined using a hot gas extraction method and carbon is determined proceeding from the chemical composition of the deposited and base materials. It is established that the chromium and nickel content in points of the welded section with an entirely austenitic microstructure is specified by coordinates Creq and Nieq in accordance with the austenite-martensite boundary proposed by Kotecki. Therefore, the results obtained confirm the possibility of predicting welded section microstructure from the position of this boundary, even in the case of joints welded with a laser beam with moderate solidification and cooling rates.
Keywords: clad steel; welding; laser beam; welded section; austenitic microstructure

Complex Mathematical Model of the Distribution of Multicomponent Charge in a Blast Furnace by N. G. Ivancha; I. G. Murav’eva; E. I. Shumel’chik; V. I. Vishnyakov; Yu. S. Semenov (95-100).
We present the results of development of a complex mathematical model of formation of multicomponent batches of charge materials, their charging into the hopper of a bell-less top system, discharging from the hopper, and distribution over the backfill surface and show the possibilities of its technological application. The results of mathematical modeling can be used to improve the applied modes of charging and correct these modes in the case of addition of new components into the charge, they allow us to analyze the influence of the applied program of distribution of charge materials on the distribution of individual components (both in the iron ore and fuel parts of the charge), which makes it possible to select and adjust the program according to the results of predictive calculations prior to entering it into the charging control system. It is shown that the application of the mathematical model gives a possibility of making substantiated choice of rational parameters of the modes of charging of multicomponent charge and decreases the level of hazard of making inefficient decisions.
Keywords: blast furnace; blast-furnace smelting; mathematical model; charge materials; program of charging; bell-less top charging system; ore burden; multicomponent charge; skip charging; conveyor charging; backfill surface; pellets; agglomerate; coke; skull

Simulation of Bending of Heavy-Duty Components of Stands in a Five-Stand Longitudinal-Wedge Mill by S. A. Mashekov; A. E. Nurtazaev; E. Z. Nugman; B. N. Absadykov; A. S. Mashekova (101-110).
A longitudinal-wedge mill of new design is proposed. We present the analysis of the results of mathematical modeling of the elastic deformation of heavy-duty components of the stands of the new mill with the use of the procedure of computer simulation by the finite-element method in the PATRAN-NASTRAN environment. The influence of changes in the diameter of working rolls of the longitudinal-wedge mill on the elastic deformation of heavy-duty components of the stands of the mill is determined. It is shown that the new mill is characterized by a fairly high stiffness of the structure of stands and satisfies the conditions of strength. It is indicated that the process of rolling of strips on the proposed mill makes it possible to obtain finished rolled products without variations in thickness in the longitudinal and transverse directions. As a result of modeling of elastic deformation of the heavy-duty components the stands of the new mill, we develop special measures for their modernization.
Keywords: longitudinal-wedge mill; rolls; stands; bearings; elastic deformation; thin strip; variations in thickness; flatness

The problem of energy consumption in the ferroalloy industry has become an enormous challenge as the cost of energy permanently increases, while the reserves of good-quality raw materials are decreasing. Hence, the valorization of low-quality raw materials becomes necessary under the conditions of keeping the quality of products within the marketable range and low energy consumption. From the history of smelting of manganese alloys, it is known that the priority was always given to high-grade manganese-oxide ores because the quality of the ore has a great influence on numerous important parameters. This was mainly connected with the pyro metallurgical advantages offered by high-grade ores, including high manganese content (minimizing the materials consumption), lower power consumption caused by its oxide nature, and high fusibility. However, in the last 50 years, the ferroalloy industry faces the problem of application of the carbonate ores with an aim to compensate the depletion of the reserves of oxide manganese ores and meet the requirements of steelmaking in which manganese alloys find their primary use. In the present work, we study two manganese ores, namely, pure oxide and carbonate ores. A jones riffle was used for sample preparation. A jaw crusher and zip mill were used to decrease the size of particles, a graphite crucible was used as the container of the ore, and an induction furnace was used for smelting. Various proportions of oxides and carbonates manganese ore were mixed and smelted at 1550°C in the argon atmosphere for 1 h. The investigations of the ores and products were carried out by using the x-ray diffraction (XRD) method, an ICP-OES spectrometer, and a scanning electron microscope with energy dispersive spectrometer. It was shown that a marketable high-carbon ferromanganese can be produced with at least 75% Mn and a slag containing less than 20% MnO. The results obtained for oxide-carbonate blends with 90–10%, 80–20%, 70–30%, 60–40%, and 50–50% ratios met market requirements. However, the results accumulated for oxide-carbonate blends with 20–80% and 0–100% ratios showed that the alloys obtained as a result of smelting contained only 48% Mn and 68% Mn, respectively, despite the fact that the slag contained ≤20% MnО.
Keywords: low-quality ore; manganese; valorization

Improvement of the Uniformity of Blast Distribution over the Circumference of Blast-Furnace Hearth by V. P. Lyalyuk; A. K. Tarakanov; D. A. Kassim; I. G. Riznitskii (119-124).
A problem of the technology of blast-furnace smelting connected with the necessity of guaranteeing the uniform distribution of the blast rate along the circumference of blast-furnace hearth remains unsolved up to now. The degree of stable nonuniformity of the blast rate over the circumference of blast-furnace hearth caused, first of all, by the design of the joint of a straight-line air channel and an annular channel can be significantly reduced by realizing two-sided diametrically opposite hot-blast supplies from the straight air channel to the annular channel.
Keywords: blast-furnace smelting; blast rate; nonuniformity; air channel

Features of Steel ChS-82 (04Cr14Тi3B1V) Cyclic Electroslag Remelting by L. Ya. Levkov; M. A. Kissel’man; D. A. Shurygin; S. V. Orlov; A. A. Garchenko; P. M. Yavtushenko (125-131).
A trend in the development of modern electroslag remelting is the use of the ESR technology with replaceable consumable electrodes during melting and protection of smelting space by an inert gas in a cyclic electroslag remelting (CESR) regime. Industrial development of this technology at domestic enterprises is at an initial stage, and many questions related to features of remelting of high-alloy steels and alloys have not been studied practically. Information presented in this article reflects results of studying the CESR process in a model furnace EShP-0.5U of RPA TsNIITMASh and industrial smelting in the EShP-9.8 furnace of Ruspolimet.
Keywords: cyclic electroslag remelting; consumable electrode replacement; flux; melting weight rate; metal bath shape; metal utilization factor

We examine the parameters for hot straightening of steel plates, taking into account deformation of the metal on the rollers during alternating bend process, as well as the temperature and strain rate. The calculations showed that deformation, temperature, and strain rate have a significant impact on the bending moments and the straightening force; these must be taken into account in the design and operation of roller straighteners. The approach used for straightening steel plates is used to calculate the operating parameters of plate straightening machines.
Keywords: hot straightening steel plates; roller straightener; alternate bending; bending moment; straightening power

The effect of structural characteristics (ferrite, ferrite + pearlite, sorbite) including morphology, size and distribution of nonmetallic inclusions of different morphology, sizes and distribution, on ductile–brittle transition in structural steels is considered. It is shown that an elementary ductile microcrack is initiated by particles of critical size. For steels with ferrite-pearlite and sorbite microstructure, the particle size (carbide, nitride and nonmetallic inclusions) is almost the same. The ductile–brittle transition is caused by competition of the size of the brittle and ductile (pits) microcracks. As a result, the critical brittleness temperature T c in simplified form looks like Tc=Tc0+BΛd1/2/Λb, $$ {T}_c={T}_c^0+B{Lambda}_d^{1/2}/{Lambda}_b, $$ where elementary microcracks Λ b and Λ d correspond to the size of a brittle crack of transcrystalline cleavage (Λ b ) and the size of ductile crack (Λ d ), Т c 0 reflects the contribution of different strengthening mechanisms to metal yield strength: dislocation, solid solution, grain size, precipitation hardening, and others, and B is a coefficient taking into account the stress-strain state in the fracture zone. As part of this model of failure, it becomes clear why for hardened steel the grain size does not change up to the recrystallization temperature, and yield strength and the value of T c have a complex dependence on the tempering temperature. Since the steel has particles of different sizes, they initiate the occurrence of pits of different sizes. The larger the particle, the sooner a micropore originates around it and pit growth is faster. A wide range of pit sizes arises that causes a wide range of T c values. A close connection is demonstrated for the width of the ΔT c ductile–brittle transition temperature range with a change in the distance between particles, including between pearlite colonies. This relationship can be positive and negative, which is confirmed by experiment.
Keywords: critical brittleness temperature; ductile–brittle transition; structure; nonmetallic inclusions; extent of ductile–brittle transition; brittle microcrack; pit

Experiment for Use of Bratsk Aluminum Plant Technogenic Waste as a Reducing Agent During Cast Iron Smelting by N. V. Nemchinova; P. A. Yakushevich; A. A. Yakovleva; L. V. Gavrilenko (150-155).
The fundamental possibility of recycling fluorocarbon-containing waste generated in producing primary aluminum is demonstrated. Technogenic waste of electrolytic production may be used as raw material for other branches of industry, and, in particular, it may compete with oven coke in the steel industry. When using RUSAL Bratsk fluorocarbon-containing waste (carbon foam flotation tailings, gas cleaning slurry, and electric precipitator dust) as reducing agents, good metal extraction from iron-ore concentrates of Korshunovskii Mining and Enrichment Combine is achieved. Research results show that use of waste when smelting in a briquetted form (carbon content on average up to 55%) permits extraction of up to 94% iron, which is comparable with experience in the use of oven coke for cast iron production.
Keywords: aluminum production; fluorocarbon-containing waste; reducing agent; melting; cast iron

It is shown that addition of rare earth metals to cast corrosion-resistant high-temperature alloys facilitates a reduction in harmful impurities (oxygen, nitrogen, sulphur) and substantially increases operating characteristics. The microstructure in cast condition and after complete heat treatment is typical of hightemperature nickel alloys. It is established that exceeding the optimum REM content leads to eutectic γ′-phase melting that may cause a reduction in operating properties. The introduction of waste, including substandard materials, during melting does not lead to a reduction in operating properties.
Keywords: corrosion-resistant alloy; melting; impurities; rare-earth metals; microalloying

Autoclave Leaching of Rare-Earth Metals from Hydroxide Precipitate by K. N. Nesterov; K. M. Smirnov (163-168).
Results of experiments on autoclave leaching of rare earth metals (REM) from hydroxide precipitate, obtained after alkaline atmospheric leaching ores of Tomtor deposit, are presented. It is established that autoclave leaching in the presence of oxygen makes it possible to increase the efficiency and selectivity of the process and to increase REM extraction by up to 10–13%. The main parameters of autoclave nitric acid leaching are as follows: initial HNO3 concentration 350 g/dm3; temperature 120°C; oxygen partial pressure 0.3 MPa; L:S = 5.0 (wt.); time 2 hours. In the optimum regime selected, 98.0–98.5% of REM is extracted into solution.
Keywords: deposit; rare earth metals; monazite; autoclave; nitric acid; leaching; oxygen; hydroxide precipitate

Methods and Equipment for Breaking Down Gold-Containing Concentrates from Lean Ores and Mining Industry Waste by Yu. N. Mansurov; Yu. A. Miklin; N. A. Miklin; A. V. Nikol’skii (169-175).
Exhaustion of rich or readily enriched precious metal ores leads to involvement in operation of stubborn ores from which effective extraction of precious metals by traditional methods is impossible. Within stubborn ores, a considerable part of gold is finely associated with sulphide minerals, generally with arsenopyrite and pyrite, and remains inaccessible for leaching even with fi ne comminution. Presence of an active carbonaceous agent occluding cyanide complexes of gold from solutions is another reason for stubbornness of gold-bearing ores. The joint negative effect of both factors on enrichment gives rise to doubly stubborn ores. A reduction in gold extraction indicators during hydrometallurgical processing for ores and concentrates with sorption and active organic carbon is overcome in most cases by using ion-exchange resins and activated carbon, whereas recovery of gold bonded in sulfides requires breakdown of the mineral crystal lattice. For this purpose, oxidizing roasting, and autoclave or bacterial oxidation of sulfides in a pulp are usually applied. The last two methods are now the most widespread. At the same time, roasting gold ores and concentrates is applied at a number of the overseas enterprises. This shows that hightemperature processes remain the main methods for preparing gold-bearing ores and concentrates for leaching. On the basis of results of calculations, research, and design and engineering development, and industrial tests the authors conclude that it is possible to increase extraction of gold and silver in products from the Mai and Badran fields after pyrolysis in a rotary drum furnace. Compared with oxidizing roasting environmental protection issues are resolved. Procedures and production equipment schemes are developed.
Keywords: gold; precious metals; concentrates; recovery; cyaniding

A method for calculating the thickness of thermal-spray aluminum coating used to effectively protect low-alloy steel during heating for rolling is developed. The method calculates the thickness of the diffusion layer, taking into account the variation in the surface temperature of the workpiece and the dependence of a parameter proportional to the diffusion coefficient on temperature in a range of 700–1200°C.
Keywords: thermal-spray coating; rolling; diffusion layer; oxidation; heat treatment; slab; thickness; porosity

Forging of High-Manganese Steel Crossing by Yanhui Wang; Bo Lv; Fucheng Zhang (181-184).
The thermoplastic characteristics of high-manganese steels with different phosphorus and sulfur contents were investigated. The zero-ductility temperature and plasticity-temperature range of the high-manganese steels were reduced significantly with increase in phosphorus or sulfur content. The relationship between the initial forging temperature of the high-manganese steel and the content of phosphorus and sulfur can be expressed as Tift = 1200 – 1530wS – 1650wP. The final forging temperature is 900°C, and the heating rate during the forging of the high-manganese steel crossing must be slow. The lifetime of the forged high-manganese steel crossing was almost doubled compared with conventional cast high-manganese steel crossing.
Keywords: high-manganese steel; forging; crossing