Arc Furnace Steel Research Articles

Atrazine Sorption by Biochar, Tire Chips, and Steel Slag as Media for Blind Inlets: A Kinetic and Isotherm Sorption Approach

Surface inlets are installed in subsurface drainage systems to reduce ponding duration and surface runoff, but can contribute to water quality concerns by allowing water to directly enter buried drains. Blind inlets consist of perforated pipes covered with gravel and are separated from an overlying sand layer by a geotextile membrane and have been shown to be more effective in reducing losses of sediment, nutrients, and pesticides than typical tile line risers. In this study, we investigated whether the effectiveness of blind inlets to sorb pollutants, with emphasis on the herbicide atrazine, could be further improved by amended them with materials other than limestone. The media, shredded tires (tire chips), electric arc steel furnace slag (steel slag), and oak-derived biochar were chosen because they are readily available, inexpensive, and do not present environmental concerns. Kinetic sorption and isotherms were determined to ascertain atrazine sorption by these materials, in addition to testing for potential metal leaching using the Synthetic Precipitation Leaching Procedure (SPLP) and the Toxicity Characteristic Leaching Procedure (TCLP). The kinetic data were fitted using pseudo first- and second-order reaction equations and indicated that atrazine sorption rate was 38 times faster and equilibrium was reached 5 times earlier for biochar than tire chips. The 24-h sorption isotherm data were fitted to the Freundlich sorption equation. The sorption coefficient for biochar was higher than for tire chips, steel slag, and limestone. Per the SPLC and TLCP tests, there was no leaching of heavy metals at levels of environmental concern. Our results suggested that the effectiveness of blind inlets as well as other conservation practices that include filter media such as rain gardens and filter socks could be improved by incorporating more reactive materials than sand and gravel with biochar being a particularly effective alternative.

Modification of steel with barium and strontium

The modification of steel by natural materials containing barium and strontium is considered. Thermodynamic modeling of the reduction of barium and strontium by silicon and aluminum is undertaken. The influence of modification by barium and strontium on the structure and mechanical properties of the steel is studied. The results are employed in the production of 25Γ2C and Γ13 steel in arc furnaces at the casting shop of OAO EVRAZ ZSMK and also in the production of 35XΓCЛ, 30XΓCЛ, and 12HЛ2ΦX steel at OAO Yurginskii Mashinostroitel’nyi Zavod by two-slag technology. The results of industrial tests indicate that modification with barium and strontium affects the microstructure and nonmetallic inclusions; and increases the margin of structural strength of the steel, estimated in terms of the yield point, strength, and impact strength at positive and negative temperatures. To identify the presence of barium and strontium in the steel, its structure is analyzed by means of extraction replicas on a transmission electron-diffraction microscope. The presence of barium and strontium within the grains indicates their reaction with the metallic melt, which affects the structure of the metallic matrix.

Production of high-manganese steel in arc furnaces. Part 1

An improved oxidative production technology for 110Г13Л manganese steel in a 25-t arc furnace is considered. The basic periods of the process are described. The slag conditions in steel production are discussed. The activity of oxygen in the metal is assessed on the basis of practical data regarding the slag composition in the oxidative and reductive periods. The oxygen activity in the metal is plotted as a function of the total content of manganese and iron oxides in the slag. In addition, a method is proposed for determining the required aluminum content for reduction of the metal, so as to obtain the required quantity in the final melt. The influence of the steel’s aluminum content on its impact strength is investigated.

Mathematical Simulation of Acoustic Characteristics of Super-Power Arc Discharges in Electric Steel Furnaces

Mathematical model of appearance and progress of noise characteristics in super-power electric arc steel furnaces is considered in the paper. It is shown that noise generation is coupled with pulsations of axial plasma flows in arc discharge caused by fluctuations of electrodynamic pressure on discharge column formed by interaction between its own magnetic field and current flowing in the arc. Simulation results have shown that pressure in arc axis alternates at frequency 100 Hz with amplitude 6600 N/m2 for arc current 80 kA. Basic frequencies of arc noise are aliquot to 100 Hz, that fact is verified by exploitation practice of arc steel furnaces. Sound intensity level in workspace riches 160 dB, but thanks to shielding by case and fused metal and slag it falls to 115–120 dB on service area of furnace. It has shown that maximal amplitudes in frequency spectrum of the noise are in range 5–150 Hz. Generated noise amplitudes and frequency ranges depend on arc discharges' resistance, which are defined by ionization level of gases. According to Saha equation, iron vapor is ionized by 70 %, calcium vapor – by 95 %, and ionization level of air is no more than 1.5 %. It has been experimentally shown that in melting of stock coated with lime noise intensity is decreased by 6–8 % against no-lime iron melting because of lower calcium ionization potential (6.11 eV). It has been ascertained that for long arc with high voltages the sound intensity is decreased by 3–4 % as compared with short arc of the same current. It has shown that suppression of low-frequency components of noise energy is possible by optimization of electromechanical oscillations of electrodes, electrode-holders and cable strips, additionally to inclusion lime in stock mixture. The appropriateness of improvement electric arc furnaces hermeticity and development of the furnaces for operation with lowered currents and enlarged transformers' voltages have been approved.

ARC FURNACE WATER COOLED ELEMENTS HEAT WORK ESTIMATION AT DIFFERENT CONSTRUCTION ELECTRODES APPLICATION

The article discusses the increase in efficiency of the water-cooled heat elements of modern electric arc furnaces using mathematical modeling using electrodes of different design, namely conventional (solid) and hollow (tubular). In the mathematical modeling showed that the use of hollow (tubular) electrodes can significantly improve the thermal performance of water-cooled elements arc steel furnaces, reduce the amount of heat loss of 120 kW/m2. The results of computer simulations are in qualitative agreement with the data on physical models, thus promising applications of hollow (tubular) electrodes in a production environment.

Performance of Steel Slag in Highway Surface Course

As the quantity of disposing waste material is increasing in road construction, researchers are exploring the use of alternative materials which could preserve natural sources and save the environment. One of these sustainable materials is steel-furnace slag which is a synthetic aggregate produced as a consequence of the electric arc furnace (EAF). Steel slag was selected due to its characteristics, which are almost similar to conventional aggregates, and the fact that it is easily obtainable as a by-product from the steel industry. The same gradations of mixtures were produced using normal crushed aggregate as control samples. The experimental research has been articulated in a preliminary study of the chemical, leaching, physical, and mechanical properties of the electric arc furnace (EAF) steel slag. In addition, the outstanding benefits of steel slag were highlighted. All the mixtures with EAF steel slag have satisfied the requisites for acceptance in the road sector technical standards, thus resulting as suitable for use in the construction of road infrastructures.

Reasonable application analysis of Casnter graphitization furnaces according to the demands of modern market

Analysis of the global market has shown that the production of graphite electrodes (GE) depends on the production of steel in electric arc steel furnaces. The growth of world production is the main driver of the market development of graphite electrodes.Acheson-type graphitization of GE was extremely energy intensive and therefore costly, but was necessary to manage previously poor coke qualities with high sulfur and nitrogen content. Although invented earlier, the more economic Castner, or so called lengthwise graphitization, was not applicable until the development of electrical rectifiers for these high currents. As these became available and needle coke with low sulfur and nitrogen was invented, lengthwise graphitization became the standard in the Western World for GE production.Manufacturing requires high-quality large-diameter electrodes. They must be technically and economically advisable for the usage only in directly-fired furnaces by Castner method. But the given technology is not fully realized in Ukraine. First of all, it`s so due to the absence of significant investment in electrode industry. Although, as the analysis of modern market of electrode industry has shown, the situation is changing and new requirements are emerging now.

Fatigue Performance of Asphalt Concretes Made with Steel Slags and Modified Bituminous Binders

This paper describes the results of a research aimed at investigating the fatigue resistance performances, determined by means of the four-point bending test (4PBT), of bituminous mixtures (SMA and traditional ones) for base courses and wearing courses, made with Electric Arc Furnace (EAF) steel slag and bitumen modified with crumb rubber or SBS polymers. The fatigue behaviour was also studied after long-term ageing, in order to check the effectiveness of the crumb rubber modification (by wet process) in reducing the fatigue damage in heavily oxidized mixtures. For both unaged and aged conditions, the asphalt rubber mixes presented better fatigue behaviour than the reference mixtures made with polymer modified bitumen.

Slag oxidation in arc furnaces

In the electrosmelting shop at OAO MMK, the smelting of steel in powerful DSP-180 arc furnaces introduced in 2006 continues to be refined. Industrial research is conducted to establish how the content of the iron oxides FeO and Fe2O3 in the slag depends on its total oxidation. As a result, the dependence of FeO/Fe2O3 on the total slag oxidation may be described. It is established that the total slag oxidation does not depend on the consumption of injected carbon in frothing the slag. Analysis of the waste gases in the same smelting period shows sharp increase in the content of carbon oxides (especially CO) and the temperature. On account of the poor assimilation of the injected carbon by the melt, much of it is oxidized in the gas phase.

Effect of the purity of oxygen used for blowing on the nitrogen content of steel made in high-power arc steelmaking furnaces at ural steel

Given the high rate of injection of steel with oxygen in modern high-power arc steelmaking furnaces (close to the rate attained in basic oxygen furnaces), the purity of the oxygen becomes the deciding factor in determining the nitrogen content of the steel. An analysis is made of the factors that affect nitrogen content in the production of steel in modern electric-arc furnaces at Ural Steel. In particular, a determination is made of the extent to which the purity of the oxygen that is used affects the steel’s nitrogen content. The injection of steel with oxygen in modern high-power arc steelmaking furnaces ‐ which is done to speed up melting of the scrap and oxidation of the impurities in the charge ‐ is carried out at very high rates. For example, the highest injection rate on arc furnaces Nos. 1 and 2 in the electric steelmaking shop at Ural Steel is 12000 m 3 /h. At rates this high (close to the rates used in basic oxygen furnaces), the purity of the oxygen is of critical importance because its injection can change the nitrogen content of the steel. Thus, basic oxygen furnaces and all large modern arc steelmaking furnaces (ASFs) are operated with the use of commercially pure oxygen (O 2 content no lower than 99.5%). The literature data [1‐10] and experience with the operation of basic oxygen furnaces show that even a slight decrease in the purity of the oxygen (at high rates of injection) has a marked effect on the nickel content of the steel. As regards the effect of the parameters of the injection of steel with oxygen (oxygen consumption, oxygen purity) on furnace performance, the technical literature offers complete information only for converters and less productive arc steelmaking furnaces used earlier. No such investigations have yet been conducted for modern ASFs. Thus, Ural Steel performed an analysis of different heats in order to refine information on the factors that affect nickel content when steel is made in modern electric-arc furnaces. Also, since many metallurgical plants cannot use commercially pure oxygen when making steel in arc furnaces (due to the lack of a modern oxygen plant or a deterioration in the condition of the existing plant), they employ industrial-grade oxygen (with an O 2 content below 95.0%). There may be a significant difference in the nickel contents of steel made using oxygen of commercial and industrial purity. Use of the latter makes it more difficult to produce grades of steel used in critical applications, such as tube steels. The nickel content of such steels cannot be any greater than 0.008%. To determine the extent to which the purity of the oxygen used in the steelmaking operation affects the steel‘s nickel content, we analyzed heats made with the use of oxygen of different degrees of purity. Method of investigation. The trial heats were made in 120-ton arc steelmaking furnaces Nos. 1 and 2 at Ural Steel with the use of up to 45% liquid pig iron in the metallic part of the charge. This part of the charge was introduced into the

Analysis of dynamics of electric-mode control system for an arc steel furnace

Recommendations on the stabilization of dynamic processes and extension of the range of stable electric-mode control for arc steel furnaces with differential error meters are presented.

Investigations on phosphorus recovery and reuse as soil amendment from electric arc furnace slag filters

Electric arc furnace (EAF) steel slag has been identified as an effective filter material for the removal of phosphorus (P) from both point and non-point sources. To determine the feasibility of land-applying P saturated EAF steel slag this study was undertaken to investigate (i) saturated EAF steel slag material's potential as a P fertilizer or soil amendment and (ii) P desorption and metals leachate from saturated EAF steel slag material to surface runoff. Medicago sativa (alfalfa) was planted in a nutrient depleted washed sand media. Phosphorus was added either as saturated EAF steel slag or as a standard commercial phosphate fertilizer in order to assess the plant availability of the P from saturated EAF steel slag. Four different P application levels were tested: a low (20 lbs acre furrow slice−1 (5.5 g P m−3)) two medium (40 and 60 lbs. acre f.s.−1 (11 and 16.5 g P m−3)) and a high (120 lbs. acre f.s.−1 (33 g P m−3)). The above-ground biomass of half of the plants was harvested after 5 weeks and the second half at 10 weeks. All treatments regardless of the P source used showed high rates of germination. At the first harvest period (5 weeks) significantly higher above-ground biomass (p < 0.01) was seen at the 3 highest P amendment rates in treatments with triple super phosphate fertilizer (TSP) than with EAF steel slag. However, by the second harvest (10 weeks) only the highest amendment rate of TSP showed a significantly higher amount of biomass (p < 0.01), suggesting that EAF steel slag might be an effective slow release P source. In a second experiment, a rain simulator was used to assess desorption of DRP, TP and metals from a saturated and semi-saturated EAF steel slag. The results revealed that the total amounts of DRP and TP released to surface runoff from EAF steel slag were negligible when compared to the total quantities of P retained by this material. Overall the results from this study demonstrated that once the EAF steel slag filter reaches its saturation point, the material could be re-used as soil amendment for the slow release of bioavailable P with minimal risk for loss of P to surface runoff, bringing further benefits to the environment.

Reducing metal losses when smelting steel in high-power arc furnaces

The heat transfer in arc furnaces with high input power is considered, in the case of induced slag foaming. Most of the power is consumed in evaporation of the metal and slag at hot spots under the electrodes and in zones of oxygen injection.

Features of a technology for making steel in 180-ton arc furnaces in the electric steelmaking shop at the Magnitogorsk Metallurgical Combine

This article presents the main specifications of arc furnaces that have been installed in the electric steelmaking shop at the Magnitogorsk Metallurgical Combine. One feature of these furnaces is that they can be operated with the use of liquid pig iron. Here’ the amount of pig iron in the charge can be as high as 40%. The use of liquid pig (up to 30%) shortens the refining operation in the furnace.

Deoxidizing slag in making low-carbon steel in 100-ton arc furnaces

Deoxidizing slag in making low-carbon steel in 100-ton arc furnaces

Improvement in the technicoeconomic indices of the decarbonization process in the making of stainless steel in 100-ton arc furnaces

Improvement in the technicoeconomic indices of the decarbonization process in the making of stainless steel in 100-ton arc furnaces

Behavior of nitrogen during the production of welding steel in five-ton arc furnaces

The heats established that, using the normal steelmaking practice for arc furnaces (with oxidizing and reducing periods), the nitrogen content of low-alloy welding steel fluctuated from 0.0132 to 0.0180%,* which considerably exceeds the norm (GOST 2246-70). It was determined that 55% of the total nitrogen in the steel was introduced by the charge, 28.5% was from the furnace atmosphere, 12.5% entered from the air during tapping and teeming, and 4% was introduced by ferroalloys and coke fines. The greatest increase in the nitrogen content of the steelmaking occurs during the reducing period, and a substantial portion of the total nitrogen is introduced during tapping and teeming. Figure 1 shows a cu~Te of the change in nitrogen content over time, averaged for six heats.

Calculation of steady state temperatures in graphite electrodes in an electric arc steel furnace

Steady state temperatures in graphite electrodes while conducting current into a molten steel bath in an electric arc steel furnace have been calculated for three cases of practical interest: 1. (a) the radial temperature distribution in a region of the electrode far enough away from the tip and the holder so that there is no axial temperature gradient and heat flow, 2. (b) the radial and axial temperature distribution in the region near the tip of an electrode with uniform diameter and flat end face, and 3. (c) the radial and axial temperature distribution in the region near the tip of a tapered electrode with a flat end face. The method of calculation and computer programs are described, and the dependence of the temperature distribution on the electrode size and the magnitude of the current is given.

Carbon, Graphite, and Contacts

The black art of carbon and graphite technology is yielding to the science of materials and applications. This review represents the present state of this art; and since carbon, graphite, and contacts come together in so many different ways and in so many important ways, it is reasonable to discuss them in this context. From the developments in this field have come materials which have made possible such applications as electric arc steel furnaces, jet aircraft engines, high altitude aircraft, inexpensive appliances, aluminum reduction pots, electric machines, electric traction, and many other uses. The purpose is to discuss the fundamental physical processes involved in sliding conduction, friction, and the electric arc, and the roles that carbon and graphite play. To put this together, we will first discuss the pertinent properties of carbon (1), then the physical and chemical effects involved in contact drop, mechanics, friction, temperatures, the electric arc, commutation, and wear (2). The principles are similar for both electrical and mechanical sliding contacts, that is, for brushes and for seals and brakes, so all will be included. Furthermore, in a suitable application, all of the applicable phenomena must be coordinated and within practical operating limits. In most applications, many of'the phenomena are interdependent in that they influence each other and are all influenced by the ambient conditions surrounding the ap- plication.

Refractory properties of siliceous bodies for ramming the linings of acid arc steel furnaces

Refractory properties of siliceous bodies for ramming the linings of acid arc steel furnaces