Furnace Steel Research Articles

Reduction of Irradiation Level for Personnel Working in a Steel Furnace Using NMG Method

The humidity of coke introduced into furnace used for preparation of cast-iron plays an important role in development of metallurgical processes. More that its importance results from the necessity to optimization of the energy consumption in the furnace. Therefore, the quick, precise, and in situ measurement of the humidity of coke is necessary and a decisive process in cast-iron preparation. In this aim, the nuclear moisture gauge (NMG) method is successfully used. Two main issues appear in this case. First of them concerns to the NMG calibration and second refers to get rigorous results. The last aspect is linked of the corrections have to be made for the density measurements of coke, during performing of a NMG measurements occurring into continuous flow. During humidity measurements it is necessary to take into consideration of the irradiation level of the workers performing calibration and moisture measurements implied by the NMG. The paper reveals and discusses the results concerning the use of the NMG technique without automatic density correction as compared to the NMG technique which users the automatic density corrections. The humidity of coke used in furnaces was monitored for several months by using both techniques and their results are compared. The linear dependence between the NMG indications and coke humidity is not influenced of the coke granulation. It is concluded that the NMG without automatic density correction gives as good results as the more complicated, much more expensive and, mainly, more radiation exposing of workers NMG method with automatic density correction.

Application of Ground Granulate Blast Furnace Slag-Steel Slag Composite Binder in a Massive Concrete Structure under Severe Sulphate Attack

A composite mineral binder was prepared by mixing ground granulate blast furnace slag (GGBS) and steel slag (GGBS/steel slag ratios are 1 : 1 or 3 : 2 by mass). The application of a composite binder in a massive concrete structure under severe sulphate attack is discussed by determining the hydration heat, adiabatic temperature increase, compressive strength, elastic modulus, chloride ion permeability, and sulphate attack resistance. The results show that the hydration heat of the composite binder decreases greatly when the cement replacement ratio increases to 50% at 45°C. The adiabatic temperature rise of the concrete containing the composite mineral admixture decreases significantly. Concrete containing the composite mineral admixture has a lower early elastic modulus and satisfactory late-age compressive strength. The composite mineral admixture can improve the resistance to chloride ion permeability and sulphate attack resistance of concrete, especially during temperature match curing.

Research experiences on the reuse of industrial waste for concrete production

The aim of this study was to assess the feasibility of concrete production using different kinds of industrial wastes as “recycled aggregate”. The wastes studied in this work were: fly ashes and slags from Electric Arc Furnace (EAF) steel plant; foundry sands produced from foundry dies; slags from lead processing; Waelz slags; solid residues from municipal solid waste incineration (MSWI) plant (with mass-burning kiln and fluidized bed reactor); sludge from industrial wastewater treatment plants. Good compressive strength (similar to natural concrete) was achieved after 28 days of curing by concrete mixtures obtained with the partial replacement (from 7% to 40% by weight) of natural aggregates with slags from lead processing, foundry sands, Waelz slags and bottom ashes from MSW incineration. The worst mechanical and leaching behaviours were shown by concrete samples containing EAF fly ashes and sludge from industrial wastewater treatment. For the residues with the best performance, concrete products (kerbs and flat tiles) were casted. Their mechanical and leaching characterization has shown that the reuse of these residues for concrete product is feasible.

The effect of electrode-holding arms on the electrical parameters of the bus-tube section of current lead in an arc steel furnace

The essence of the electromagnetic effect of metalware located near current-carrying elements has been shown. Aftereffects, such as heating of metalware, additional active losses of power supply, perturbation in the magnetic field, and consequent changes in the active resistance and inductive reactance of the equivalent circuit of a furnace have also been considered. The existing technique of taking into account the influence of metalware located near current-carrying elements on the electrical parameters of the current lead of high-power technological equipment has been examined, with its drawbacks being revealed. A method for increasing the accuracy and range of applicability of the technique has been suggested. To do this, a more universal coefficient of neighboring metalware (CNM) has been introduced. The coefficient allows us to take into account the influence of metallic structures on the resistance and magnetic reactance of the furnace circuit. The results of numerical simulations for a bus-tube section of current lead in a 100-t arc steel furnace (ASF) have been presented. The results of simulations were compared with the experimental data obtained by physical modeling of current lead of a 100-t ASF. A numerical model validated by such a way was used to obtain the dependences of active resistance and inductive reactance and CNM on the geometry of the investigated section and the properties of electrode-holding arms. The obtained dependences are the basis for an engineering technique intended to design current leads for an arc steel furnace.

Results of Modeling Operation of the High-Speed Regulator of Non-Contact Secondary Voltage of Furnace Transformer of the High-Power Arc Steel Furnace in Constant Primary Current Mode

The article describes main methods for regulation of the secondary voltage of furnace transformers (FT) of high-power arc steel furnaces (ASF), their advantages and drawbacks are outlined. Within consideration of the non-contact and high-speed regulation of FT voltage, the emphasis is put on using thyristor voltage regulator deployed in the intermediate circuit. The comparative evaluation of main energy indicators of the FT-ASF complex are given within using thyristor regulator of secondary FT voltage, and of traditional methods for controlling electric modes of ASFs by means of affecting the furnace transformed as the high-speed executive component of the regulation system. Main electric modes that can be obtained through using thyristor regulator of the furnace transformer in case of supporting the constant primary current in the FT, are considered. Results are obtained using a math model of the FT-ASF electrotechnical complex, developed in MATLAB Simulink package.

Phosphorus Sorption Capacities of Steel Slag in Pilot-Scale Constructed Wetlands for Treating Urban Runoff: Saturation Potential and Longevity

Two parallel pilot-scale integrated constructed wetland (ICW) systems were constructed on the bank of Nanfeihe River. The phosphate (PO43-) isothermal adsorption properties of the upper substrate steel furnace slag (SFS) in up-flow chamber was investigated during one-year operation period. The maximum phosphorus (P) adsorption capacity of SFS 9, 11, 13, 15, 17, 19 months service time were 848.9 mg/kg, 968.1 mg/kg, 824.5 mg/kg, 788.7 mg/kg, 864.7 mg/kg and 960.3 mg/kg, respectively. The saturated adsorption amount of SFS had not decreased with the service time prolonging in ICW. The longevity of a full-scale system could not be reliably estimated only based on the theoretical saturated adsorption capacity from laboratory experiments.

Low-cost filter media for removal of hydrogen sulphide from piggery biogas

The presence of elevated concentrations of hydrogen sulphide (H2S) in piggery biogas is problematic due to its corrosiveness and toxicity. At small scale, the cost of using iron or carbon-based commercial filter media to remove H2S can act as a barrier to the uptake of on-farm biogas technology. To identify cost-effective, alternative options, this study tested and compared H2S removal by the commercial iron-oxide H2S scavenger (cg5) with the alternative solid media: granulated steel furnace slag (GSFS), red soil, compost, composted beef feedlot manure, granular activated carbon (GAC) and biochar. Experiments measured single-pass H2S removal from a pre-humidified standard gas (2000ppm H2S in nitrogen) onto solid media contained in a cylindrical plastic column (DN 25mm, depth 110–147mm). The commercial medium (cg5) performed considerably better than the other media, achieving sulphur removal of 143gS/kg medium at breakthrough (>10ppm outlet H2S). A red soil was the most promising alternative medium (2–12gS/kg medium at breakthrough). The crystalline structure of the iron-oxide minerals appeared to strongly influence the H2S removal capacity of the red soils, and pressure drop was generally high. Bulking with ground sugar cane mulch (SCM) was effective at reducing pressure drop. Interestingly, H2S removal with red soil improved when the soil was regenerated by exposure to air, followed by reuse in the column. Overall, red soil may be a suitable low-cost option, especially for polishing biogas after initial biological H2S removal.

Review of Our Investigations on Ladle Furnace

The LD-2 and slab caster shop of Tata Steel, Jamshedpur manufactures slabs. Tata Steel desired some studies on the ladle furnace (LF) of the shop. It sponsored project to Tata Research Development and Design Centre (TRDDC), Pune. It was undertaken as a collaborative work by the two organizations with team of engineers and scientists participating. The present author was then at IIT Kanpur and acted as advisor. The study was concerned with plain carbon aluminum-killed steel. The entire work was undertaken in three phases. Phase 1 involved flow and thermal modeling. Phase 2 was concerned with development of on-line reckoner (LFOR) for prediction and control of temperature and composition of molten steel in ladle furnace. Phase 3 was a short project concerned with modification of LFOR, when Tata Steel adopted Al-wire feeding at the OLP station. The present paper is a brief review of the entire work.

Study of chloride penetration in concretes exposed to high-mountain weather conditions with presence of deicing salts

The durability of reinforced concrete (RC) is a challenge. One of the most aggressive and frequent ions is chloride, which frequently affects RC structures by steel corrosion. Many studies have concluded that the use of mineral admixtures improves concrete durability. This paper examines the transport process of chloride ions in non-saturated concrete. Three types of concrete have been designed and tested: the first one with only CEM I 52,2 R (CP), the second with 10% of silica fume (CPHS) and the third with 20% of blast furnace slag (CPEAH). An experimental programme was designed with the aim of studying the influence of external condition variation in a high-mountain environment with presence of deicing salts. The total time duration of the programme was 210days. The specimens were conditioned at different temperatures, relative humidity and chloride surface concentrations in five phases to reproduce the seasons annually. The experimental chloride concentration profiles were obtained at the end of each phase for each concrete. These profiles were mainly influenced by two transport mechanisms: diffusion and capillary suction. The chemical chloride binding and physical adsorption of chlorides in the concretes with silica fume (CPHS) and blast steel furnace (CPEAH) were two decisive factors in the chloride penetration processes. A numerical model for simulating chloride ion transport in non-saturated concrete is presented. It considers the diffusive and advective flux. In addition, the concrete pore network and the associate properties, such as chloride binding capacity and chloride precipitation, are also taken into account. The model has been implemented in a finite element programme. The chloride concentration profiles obtained by the model at the end of each phase for each concrete properly fit the experimentally obtained.

Thermal Analysis of an Industrial Furnace

Industries, which are mainly responsible for high energy consumption, need to invest in research projects in order to develop new managing systems for rational energy use, and to tackle the devastating effects of climate change caused by human behavior. The study described in this paper concerns the forging industry, where the production processes generally start with the heating of steel in furnaces, and continue with other processes, such as heat treatments and different forms of machining. One of the most critical operations, in terms of energy loss, is the opening of the furnace doors for insertion and extraction operations. During this time, the temperature of the furnaces decreases by hundreds of degrees in a few minutes. Because the dispersed heat needs to be supplied again through the combustion of fuel, increasing the consumption of energy and the pollutant emissions, the evaluation of the amount of lost energy is crucial for the development of systems which can contain this loss. To perform this study, CFD simulation software was used. Results show that when the door opens, because of temperature and pressure differences between the furnace and the ambient air, turbulence is created. Results also show that the amount of energy lost for an opening of 10 min for radiation, convection and conduction is equal to 5606 MJ where convection is the main contributor, with 5020 MJ. The model created, after being validated, has been applied to perform other simulations, in order to improve the energy performance of the furnace. Results show that reducing the opening time of the door saves energy and limits pollutant emissions.

Utilisation of steel furnace slag coarse aggregate in a low calcium fly ash geopolymer concrete

This paper evaluates the performance of steel furnace slag (SFS) coarse aggregate in blended slag and low calcium fly ash geopolymer concrete (GPC). The geopolymer binder is composed of 90% of low calcium fly ash and 10% of ground granulated blast furnace slag (GGBFS). Mechanical and physical properties, shrinkage, and detailed microstructure analysis were carried out. The results showed that geopolymer concrete with SFS aggregate offered higher compressive strength, surface resistivity and pulse velocity than that of GPC with traditional aggregate. The shrinkage results showed no expansion or swelling due to delayed calcium oxide (CaO) hydration after 320days. No traditional porous interfacial transition zone (ITZ) was detected using scanning electron microscopy, indicating a better bond between SFS aggregate and geopolymer matrix. Energy dispersive spectroscopy results further revealed calcium (Ca) diffusion at the vicinity of ITZ. Raman spectroscopy results showed no new crystalline phase formed due to Ca diffusion. X-ray fluorescence result showed Mg diffusion from SFS aggregate towards geopolymer matrix. The incorporation of Ca and Mg into the geopolymer structure and better bond between SFS aggregate and geopolymer matrix are the most likely reasons for the higher compressive strength observed in GPC with SFS aggregate.

Mathematical model of layered metallurgical furnaces and units

The basic approaches to mathematical modeling of the layered steel furnaces and units are considered. It is noted that the particular importance have the knowledge about the mechanisms and physical nature of processes of the charge column movement and the gas flow in the moving layer, as well as regularities of development of heat- and mass-transfer in them. The statement and mathematical description of the problem solution targeting the potential gas flow in the layered unit of an arbitrary profile are presented. On the basis of the proposed mathematical model the software implementation of information-modeling system of BF gas dynamics is carried out. The results of the computer modeling of BF non-isothermal gas dynamics with regard to the cohesion zone, gas dynamics of the combustion zone and calculation of hot-blast stoves are provided

EFFECT OF MOISTURE DAMAGE ON GAP-GRADED ASPHALT MIXTURE INCORPORATING ELECTRIC ARC FURNACE STEEL SLAG AND COPPER MINE TAILINGS

Water damage is a vital factor affecting the durability of gap-graded asphalt. There is an urgent need for a pragmatic and reasonable test to evaluate this parameter. Previous research has proposed that tensile strength ratio is a promising test for this application. Therefore, the aim of this paper is to evaluate the effect of moisture damage on gap-graded asphalt mixture incorporating electric arc furnace (EAF) steel slag and copper mine tailings (CMT). Four material mixtures of eight mix designs were investigated. Each mix was conditioned in water for 24-hour and 48-hour before testing. The study adopted retained strength index (RSI), durability index (DI) and tensile strength ratio (TSR) to describe the durability of gap-graded asphalt incorporating EAF steel slag and copper mine tailings. The results reveal that all the mixes fulfill the prescribed criteria. Also, there is a strong correlation between the retained strength index and the durability index with a strong coefficient of determination, R2 of 0.9543. The results of the study further showed that gap-graded asphalt mixture incorporating EAF steel slag and copper mine tailings did not seem to pose any problem.

Reducing the high-temperature loss of steel in furnaces

Assessment of the loss of steel in industrial furnaces may be based on the scale thickness. Means of reducing the oxidation of steel are evaluated. Special attention is paid to the difficulty of reducing the steel loss on account of decrease in the oxidant consumption n. Nonoxidative heating of steel in industrial furnaces is shown to be feasible at present. The requirements here are practically molecular mixing of the components in primary combustion (for natural gas with air excess n = 0.48–0.5); synchronous burner operation and constraints on the oxidation n with regulation of the primary fuel combustion (Δn ≤ 0.01); and effective choking of the primary gas flux so as to rule out inverse circulatory motion of the products of incomplete primary combustion from their combustion zone into the metal-heating zone. Design approaches and operating conditions for forging and rolling furnaces are proposed, so as to reduce or suppress steel losses. Particular attention is paid to the internal high-temperature oxidation of silicon in transformer steel and the decarburizing heating of ball-bearing steel.

An appraisal of the need for infrared radiation protection in sunscreens.

Many sunscreens incorporate agents that are said to protect against infrared (IR) damage in the skin but we lack any real data on their benefit in the context of normal human behaviour in the sun. The object of this study was to examine typical IR exposure levels to the sun and industrial sources in order to decide whether there is a need for sunscreens to contain agents that protect against IR radiation, specifically the IR-A waveband. We reviewed claims currently made by products offering protection against IR-A and studies on the biological and clinical effects attributed to IR-A, and compared IR-A exposure levels from these studies with those typically received from the sun and from industrial sources. We found that annual levels of IR-A exposure resulting from typical behaviour in the sun are commensurate with those experienced occupationally by workers exposed to industrial sources of IR, such as steel and glass furnaces. Yet these workers appear to suffer little in the way of chronic skin damage. We conclude that there is not compelling evidence to demonstrate that observable, deleterious cutaneous effects are occurring at doses of solar IR radiation corresponding to those experienced by populations in their normal environments and for this reason we believe it is premature to incorporate IR protection into topical sunscreens and to make claims related to ageing of the skin that consumers may expect to see.

Energy Optimization of Steel in Electric Arc Furnace

The aim of this work is to create a representative mathematical model of the process of steelmaking for the quantities of raw materials and energy consumption optimal for producing a ton of steel of the specific composition. The specific steel is grade 1010. The reaction enthalpies are critical in the conceptualization and the percentages of carbon and iron in the steelmaking process. There should be a maximum of FeO in slag and a bounded particle C. chemical reactions electric arc furnace enthalpies linear programming steel-making.

Production of high-manganese steel in arc furnaces. Part 2

Metallographic data are presented for manganese steel before and after ladle treatment—specifically, treatment with calcium–strontium carbonate or argon injection in the ladle or both. Quantitative analysis of the nonmetallic inclusions is undertaken. The position of the inclusions relative to the grain boundaries is determined. Electron microscopy permits detailed study of the composition and form of the inclusions that appear during ladle treatment and without such treatment. The influence of various types of ladle treatment on the impact strength of manganese steel is discussed. Alloying of the manganese steel with vanadium is considered. Practical data regarding the influence of alloying with vanadium on the impact strength of the manganese steel are presented.

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.