Showing papers in "Ironmaking & Steelmaking in 2007"
TL;DR: In this paper, a model based on fuzzy logic tools is presented to predict and simulate the hot metal temperature in a blast furnace (BF) using the control variables of a control board.
Abstract: The present work presents a model based on fuzzy logic tools to predict and simulate the hot metal temperature in a blast furnace (BF). As input variables this model uses the control variables of a...
56 citations
TL;DR: In this paper, uniaxial compression tests have been used to examine the bed strength of granulated single and binary iron ore sinter mixes, and the results showed that at low moistures, bed strength is dependent on the granule layer mass to nuclei mass ratio.
Abstract: In iron ore sintering, granule deformation and compaction can be responsible for significant losses in bed voidage and green bed permeability. In this study, uniaxial compression tests have been used to examine the bed strength of granulated single and binary iron ore sinter mixes. The results show that at low moistures, bed strength is dependent on the granule layer mass to nuclei mass ratio. For binary iron ore sinter mixes, bed strength was found to increase as levels of Channel Iron ore were increased. Permeability–moisture curves for a series of single ore sinter mixes were recorded to examine the key parameters that affect this relationship. The results confirmed that the porosity of the ore pore size distribution and contact angle all affect the shape or width of the curves and the moisture at maximum permeability. The height of the curves is determined by bed voidage and the granule size distribution. This study has demonstrated that provided sufficient water is available during granulatio...
54 citations
TL;DR: In this article, a viscosity model based on a new definition of basicity has been proposed for blast furnace type slags, which is applicable for a wide range of alumina, magnesia and titania containing blast furnace slags.
Abstract: A viscosity model based on a new definition of basicity has been proposed for blast furnace type slags. Conceptually, this definition of basicity is close to Bell's definition of basicity as used for modelling of sulphide capacity of blast furnace type slags. The model developed in the present work is applicable for wide range of alumina, magnesia and titania containing blast furnace slags, while most of the models available in the literature are mainly applicable for a limited range of slag composition. Viscosity estimation by this model is close to the experimental value for all types of blast furnace slags. This model is based on the chemical composition of slag and is applicable for slags above liquidus temperature.
45 citations
Journal Article•
TL;DR: The limitation of heat balance analysis, exergy analysis, energy level analysis, and related efficiency indexes is discussed in this paper, and the change of energy consumption per ton steel product of the process where the residual heat is recovered is the criterion to evaluate the perfection of thermotechnical equipment and rationality of energy utilization.
Abstract: Downtrend of energy consumption per ton crude steel of Chinese steel industry since 1980 is analyzed and the energy consumption was reduced by 48% totally,in which 56% was obtained by directly energy saving and 44% indirectly.However,Chinese steel industry still consumes 112 kg equivalent coal per ton steel more than the advanced level.The calculated residual-heat of chinese steel industry is 8.4 GJ for 1 t steel,in which only 25.8% is recovered,so residual-heat recovery will play an important role in energy saving.The limitation of heat balance analysis,exergy analysis,energy level analysis and related efficiency indexes is discussed.The change of energy consumption per ton steel product of the process where the residual-heat is recovered is the criterion to evaluate the perfection of thermotechnical equipment and rationality of energy utilization.Based on the first and second law of thermodynamics,the expression of exergy,correlated with heat efficiency and energy level difference,is deduced.Exergy efficiency and change of energy consumption per ton product were used as the evaluating indexes to analyze the current technologies for recovery of residual-heat in steel industry,and the recommended residual-heat recovery mode and its effect is introduced.
38 citations
TL;DR: In this article, B2O3-CaO (mass ratio 1 : 1) and CaF2-Cao (1 : 1)-O(1) were employed as modifiers added to the slag to reduce the melting temperature and viscosity of slags.
Abstract: Evaluation of CAS-OB refining slags showed that the melting temperature and viscosity were very high and could further increase during the CAS-OB refining process, causing excessive slag to stick to the snorkel with resulting operational problems. To avoid this, B2O3–CaO (mass ratio 1 : 1) and CaF2–CaO (mass ratio 1 : 1) were employed as modifiers added to the slag. The fusibility (melting temperature and viscosity) and desulphurising capacity of modified slag were investigated. Both B2O3–CaO and CaF2–CaO can effectively lower the melting temperature and viscosity of slag. The results of experiments on sulphur partition equilibrium between metal and slag indicate that the sulphur content of metal can be further decreased by the modified slag.
31 citations
TL;DR: In this paper, the combustion behavior of pulverised coals in a pilot plant equipped with a combustion chamber has been studied to indicate what the behaviour of each type of coal will be, when injected in blast furnace tuyeres.
Abstract: Iron ores, fluxes and tuyere injected coals used as burden materials in the blast furnace have been characterised by chemical and granulometric analysis, moisture, density and porosity, softening and melting temperatures, reductibility, X-ray diffraction, electronic microscopy and thermoanalysis. Theoretical calculations on the influence of both the chemical composition and ash content of coals on some aspects of the blast furnace operation have been carried out. The combustion behaviour of pulverised coals in a pilot plant equipped with a combustion chamber has been studied to indicate what the behaviour of each type of coal will be, when injected in blast furnace tuyeres.
29 citations
TL;DR: In this paper, a process model is proposed for designing the heating cycles for bundles of packed rods with different rod diameters, bundle diameters and packing fractions in a continuous annealing furnace.
Abstract: A typical industrial thermal processing operation has multifold complexity, with varying charge dimensions, multiple grades and inconsistent loading patterns as well as the absence of in situ sensors. These operational characteristics and restrictions invariably lead to empirical design for the temperature time cycles, which often results in suboptimal operation in terms of higher energy consumption, inconsistent quality and lower productivity. In the present work, a process model is proposed for designing the heating cycles for bundles of packed rods with different rod diameters, bundle diameters and packing fractions in a continuous annealing furnace. The process model has the capability of predicting spatial and temporal evolution of temperature and hardness in the bundle as it traverses through the furnace. Interestingly, the model based process cycles are found to be counterintuitive as compared with the empirically designed cycles normally employed in the plant. It is shown that instead of d...
28 citations
TL;DR: In this article, vanadium-rich phase(s) could be obtained in converter slags having high V2O5 contents, and the focus of the present work was to examine whether vanadium rich phase(S) could also be obtained from vanadium enriched phase(V2O 5 ) in converter SLags.
Abstract: The focus of the present work was to examine whether vanadium rich phase(s) could be obtained in converter slags having high V2O5 contents. Slags from SSAB Oxelosund, Sweden and Ma Steel, China wer ...
28 citations
TL;DR: In this article, the inclusion removal mechanism by rising bubbles around the open eye in a gas stirred ladle was investigated using a cold model, where both fine silicone oil droplets and charcoal particles were used to simulate inclusions.
Abstract: In the present study, the inclusion removal mechanism by rising bubbles around the open eye in a gas stirred ladle was investigated using a cold model. Water and silicone oils were employed to simulate liquid metal and slag respectively. Both fine silicone oil droplets and charcoal particles were used to simulate inclusions. Around the open eye, the oil layer exhibited a sphere bed structure when a critical gas flowrate was reached. The sphere bed was composed of many oil droplets, each of which was coated with a thin water film. The injected inclusions mostly followed the stream of water flow and were brought up to the open eye by the gas–water plume. A fraction of the inclusions were captured by the sphere bed when passing through the openings between the oil droplets, while the rest of the inclusions came back to the water bath and joined the stream of the flow again. The sphere bed was found to function as a filter to the tiny particles or oil droplets. On the basis of this mechanism, a prelim...
22 citations
TL;DR: In this article, the authors focused on expanding the current understanding of the mechanism of softening and melting of ferrous materials including liquid exudation and high temperature material interaction, and the results of these experiments were complimented with viscosity, surface energy and deformation rate calculations.
Abstract: This research was focused on expanding the current understanding of the mechanism of softening and melting of ferrous materials including liquid exudation and high temperature material interaction. The bulk softening and melting experiments were interrupted at temperatures of interest and samples were examined for morphological changes. The results of these experiments were complimented with viscosity, surface energy and deformation rate calculations which were helpful in understanding the melt exudation phenomenon. The microstructure of the materials showed a transition from heterogeneous to homogenous state with increasing temperatures. The melt dripping was predominantly observed in olivine fluxed pellets. The exuded slag was primarily composed of an alkali rich phase which was found least viscous of the slags present in this system. The viscosity of the liquid and the structure of metallic shell jointly control the flow of liquid from the ferrous materials. Addition of magnesia in lieu of lime...
22 citations
TL;DR: In this paper, thermal conductivities of CaO-SiO2-Al2O3 glassy slags have been determined using the nonstationary hot wire method as functions of (mol.-%Al 2O3)/(mol-%CaO) and (mol.%SiO 2 ) ratios over a temperature range 300-1270 K.
Abstract: Thermal conductivities of CaO–SiO2–Al2O3 glassy slags have been determined using the nonstationary hot wire method as functions of (mol.-%Al2O3)/(mol.-%CaO) and (mol.-%SiO2)/(mol-%Al2O3) ratios over a temperature range 300–1270 K. The thermal conductivities of the samples investigated were in the range between 1·0 and 1·6 W m−1 K−1. The thermal conductivities of samples having a constant concentration of SiO2 increased with increasing the (mol.-%Al2O3)/(mol.-%CaO) ratio as long as the constant pressure heat capacity per unit volume was kept constant. This increase in thermal conductivities would be due to increases in the speed of sound and/or the phonon mean free path by re-polymerisation of the network structure of silicate glasses by Al2O3. On the other hand, the thermal conductivities of samples having a constant value of NBO/T (the ratio of the number of non-bridging oxygen ions per tetrahedrally coordinated cation) decreased with increasing the (mol.-%SiO2)/(mol.-%Al2O3) ratio. This decrease...
TL;DR: In this article, mathematical modelling has been carried out by combining heat transfer, steel shrinkage and parabolic continuous taper model in order to optimise the mould taper profile.
Abstract: In high speed continuous casting, optimisation of mould taper is key for intensifying heat transfer and for improving the quality of the cast products. Mathematical modelling has been carried out by combining heat transfer, steel shrinkage and parabolic continuous taper model in order to optimise the mould taper profile. These models have been assembled to a set of software, the inputs of which include the steel grade, casting speed, casting temperature, length and the cross-section of mould tube, while the outputs consist of surface temperature of the strand, thickness of solidified shell, thermal linear expansion coefficient, steel shrinkage, distortion of the mould tube wall, the actual air gap, total taper and the continuous taper profile. Optimum mould taper has a parabolic profile which is tapered inwards that changes continuously along the length of the strand in order to achieve reduction in air gap while avoiding distortion of the mould tube.
TL;DR: In this paper, the physical and descriptive dimensions of steel are described, and the magnetic properties of steel have been investigated, such as the thermal expansion coefficient of austenite versus ferrite.
Abstract: There are important aspects of steel which are hidden from ordinary view and largely from the users of steels. They nevertheless determine the macroscopic behaviour. One example is that the magnetic properties of austenite determine that it has a larger thermal expansion coefficient than ferrite, whereas intuition would suggest otherwise given that austenite has a greater density. This and other aspects of the physical and descriptive dimensions of steel are described in this paper.
TL;DR: In this article, a new pickling method that reduces the metal oxide on steel strip using H2 has been studied through an extensive campaign of experimental tests, referred to as "acid free pickling".
Abstract: A new pickling method that reduces the metal oxide on steel strip using H2 has been studied through an extensive campaign of experimental tests. The process, referred to as 'acid free pickling', is environmentally friendly and does not use acid. It is most suitable for application to hot rolled low carbon steel strip. Experimental studies are in progress to validate the application of hydrogen on different metals.
TL;DR: In this article, an integrated approach is presented for maximising the productivity of a continuous annealing operation, where bundles of steel rods are annealed, where a scheduling algorithm is proposed, which is coupled with a process model.
Abstract: The operational complexities and process constraints of an industrial continuous annealing operation invariably lead to empirically designed process cycles as well as manual scheduling practices. This methodology often results in suboptimal and inefficient operations. An integrated approach is presented here for maximising the productivity of a continuous furnace, where bundles of steel rods are annealed. For this purpose, a scheduling algorithm is proposed, which is coupled with a process model. The phenomenological process model is based on heat transfer and annealing kinetics. The scheduling algorithm is formulated to analyse the continuous annealing furnace under different operating conditions. The advantage of coupling the scheduling algorithm to the process model in enhancing productivity has been illustrated. Furthermore, it is shown that optimising the bundle diameter at a constant hearth speed is favourable for frequent dispatches of the product, whereas for less frequent dispatches, it i...
TL;DR: In this article, the effects of titanium pick-up on the heat transfer and solidification nature of mold flux, when casting titanium stabilised stainless steels, were investigated by means of a specially designed experimental apparatus that could simulate the casting process.
Abstract: The effects of titanium pick-up on the heat transfer and solidification nature of mould flux, when casting titanium stabilised stainless steels, were investigated. To achieve this, the overall thermal resistance of a typical industrial mould flux was measured by means of a specially designed experimental apparatus that could simulate the casting process. The procedure was then repeated with TiO2 doped mould fluxes. A lower TiO2 content (<5%) in the test flux primarily resulted in the formation of cuspidine (Ca4Si2O7F2) upon solidification, while higher titanium levels promoted the formation of perovskite (CaO·TiO2) at the expense of cuspidine. The effect of titanium pick-up on heat transfer is largely overshadowed by the formation of a thermal contact resistance on the mould wall during flux solidification.
TL;DR: In this paper, the primary purpose of the investigation was to determine whether equilibrium conditions exist between slag and steel and inclusions and steel after silicon deoxidation and aluminium deoxideidation.
Abstract: The primary purpose of the investigation was to determine whether equilibrium conditions exist between slag and steel and inclusions and steel after silicon deoxidation and aluminium deoxidation. I ...
TL;DR: A review of alternative processes for production of high C Fe-Mn is presented in this paper, where the reduction behavior of charcoal bearing pellets with manganese concentrate at temperatures up to 1400°C is discussed.
Abstract: A brief review of alternative processes for production of high C Fe–Mn is presented. Experimental results of the reduction behaviour of charcoal bearing pellets with manganese concentrate at temperatures up to 1400°C are discussed. At temperatures up to 1000°C iron and manganese oxides are reduced to MnO, Fe and some Fe–Mn. At temperatures between 1000 and 1250°C, there is the formation of a liquid phase (Fe–Mn) by dissolution of reduced Mn into Fe. At temperatures between 1250 and 1350°C, manganese continues to be reduced and incorporated into Fe–Mn, and the composition of the metallic phase is similar to that of commercial Fe–Mn. The results have also shown that it is possible to obtain a Fe–Mn alloy with good recovery yield of Mn at temperatures within 1300 and 1400°C, without disintegration of the charcoal bearing pellet, but obtaining a liquid metallic phase inside it, favouring the coalescence of Fe–Mn. This result allows the prospect of new processes for Fe–Mn production with low energy con...
TL;DR: The stamp charging technique, the most effective among them, requires finer crushing of coal and higher moisture as binder, both requiring additional energy as discussed by the authors, while the compaction technique, which is more effective among the stamp charging techniques, requires higher moisture and fineness of coal.
Abstract: The quality of coke produced in a coke oven depends on the coal blend characteristics and carbonisation conditions. Scarcity of good quality coking coal made it necessary to look for techniques capable of producing superior coke from inferior coals. Precarbonisation techniques improve the bulk density of the coal charge and produce good quality coke from inferior coals. The stamp charging technique, the most effective among them requires finer crushing of coal and higher moisture as binder, both requiring additional energy. JSW Steel has adopted vibrocompaction along with non-recovery ovens for its 1·2 Mtpa coke production. This is a highly ecofriendly coke making process producing excellent quality coke from inferior coals. It increases the bulk density of cake, similar to stamp charging, using compaction in place of stamping. A cake density of 1·10 t m−3 has been achieved using the vibrocompacting technique with optimum moisture and crushing fineness. Coal blend containing up to 35% soft coal an...
TL;DR: In this paper, two large integral multiple alloy rotor (MAR) forgings have been successfully produced to provide an alternative to welded rotor construction for advanced turbine applications, each single piece forging comprises a CrMoV steel intermediate pressure (IP) section and a NiCrMoV low pressure (LP) section.
Abstract: Two large integral multiple alloy rotor (MAR) forgings have been successfully produced to provide an alternative to welded rotor construction for advanced turbine applications. Each single piece forging comprises a CrMoV steel intermediate pressure (IP) section and a NiCrMoV low pressure (LP) section. Special production techniques, tooling, and control methods were developed to optimize the manufacture of multi-alloy electrodes, electroslag remelting (ESR), forging, differential heat treatment and inspection. This helped attain accurate control of the chemical transition zone location, width and symmetry and lead to achievement of all mechanical properties, inspection goals and thermal stability requirement.
TL;DR: In this article, tools for quantifying the extent of alumina inclusions inside the submerge entry nozzle were developed during the present work and have been integrated with the control system of a running continuous slab casting shop.
Abstract: Deposition of alumina inclusions inside the submerge entry nozzle is a long standing problem in continuous casting of aluminium killed steel. Clogging of the casting nozzle severely affects productivity and also causes degradation of product quality. Unfortunately, very few numerical tools are available for precise quantification of the magnitude of clogging. Tools for quantifying the extent of clogging were developed during the present work and have been integrated with the control system of a running continuous slab casting shop. Reasonable match has been observed between the estimation from the developed program and the actual observations in the casting shop and subsequent products. In addition to process control, the tools were also found useful for comparing the castability of different steel grades. This feature has been utilised to study nozzle clogging during casting of steel grades that are commonly believed to have poor castability.
TL;DR: In this paper, the influence of three variables characterising the bedding piles and five sinter plant operation variables on sinter quality, Sinter plant productivity, specific fuel consumption and share of cold return fines were investigated.
Abstract: A prerequisite of a smooth operation of the ironmaking blast furnace is that the quality of the burden is stable. In blast furnaces where sinter is used as the (main) iron bearing material, its quality plays a crucial role in productivity and fuel economy. Simultaneously the corresponding factors must be considered for the sinter plant. The present paper studies the influence of three variables characterising the bedding piles and five sinter plant operation variables on sinter quality, sinter plant productivity, specific fuel consumption and share of cold return fines. Daily mean values for a period of five years of operation were used in the data driven modelling based on feedforward neural networks. The resulting models were found to describe the major changes in the outputs well. The input–output relations captured by the models were analysed by perturbing one input variable of the networks at a time and analysing the predicted behaviour of the outputs.
TL;DR: In this paper, different trials using BaO as a ladle slag tracer were performed to investigate the role of slags on the formation of non-metallic inclusions, which suggests that the slag layer that remains stuck to the ladle wall after finishing the heat may be a source of inclusions for the next heat.
Abstract: In the present paper, different trials using BaO as a ladle slag tracer were performed to investigate the role of slags on the formation of non-metallic inclusions. Results of these trials showed that the ladle slag may actively contribute to the generation of inclusions. In those heats where the tracer was added it was found that about one-third of the large inclusions detected in the final product had BaO in their composition. These inclusions may be generated by emulsification of the ladle slag during the refining stage at the ladle furnace. Additionally, inclusions containing BaO were also observed in some of the heats processed with the same ladle that previously had been used with traced slags. This fact suggests that the slag layer that remains stuck to the ladle wall after finishing the heat may be a source of inclusions for the next heat.
TL;DR: In this article, an online study on various operating parameters and slag characteristics for consistent slag splashing in a 130 t converter was carried out and an optimised slag has been developed which served effectively to balance the lining erosion during blowing and maintain a uniform thickness throughout the campaign.
Abstract: Converter lining life is an important technical and economic concern of the steelmaking process. An increase in lining life decreases refractory consumption and reduces steelmaking costs. Increased availability of furnaces increases production rates and steel yield. Extended lining life was achieved by utilising the slag as a consumable refractory by splashing it over the lining. Slag splashing is a simple and effective technique followed worldwide to increase the converter life. This paper highlights the online study on various operating parameters and slag characteristics for consistent slag splashing in a 130 t converter. Parameters such as lance height, blow pattern, gas flowrate, bottom purging flowrates, tapping temperature, combination of gunniting with splashing, slag height and slag chemistry, were investigated. An optimised slag has been developed which served effectively to balance the lining erosion during blowing and maintain a uniform thickness throughout the campaign. Some innovativ...
TL;DR: In this article, the influence of DRI usage as an alternate iron bearing metallic on the energy consumptions of electric arc furnace steelmaking (EFS) has been examined, where the authors tried to simulate some of the essential features of energy dynamics involving metallurgical aspects of directly reduced iron (DRI) smelting in EFS.
Abstract: The electric arc furnace steelmaking (EFS) process comprising an energy intensive multimetallic smelting reactor essentially meets its metallics and energy requirement with scrap and electrical energy respectively. Scrap, which leads to a substantial increase in tramp elements in steel has now been augmented by alternate metallics: hot briquetted iron, pig iron, hot metal and directly reduced iron (DRI). The melting characteristics of these alternate metallics are quite different from the melting of scrap owing to their shape, specific heat and chemical compositions. Of these metallics, the metallurgical properties of DRI are far more known and predictable. The EFS process evolution has increasingly placed emphasis on the use of DRI in its input charge mix. The present paper attempts to simulate some of the essential features of energy dynamics involving metallurgical aspects of DRI smelting in EFS. It examines the influence of DRI usage as an alternate iron bearing metallic on the energy consumpt...
TL;DR: In this article, a computer-based model using multiple linear regression techniques has been developed to guide the operator to ensure optimum consumption of desulphurisation reagent for hot metal and steel treatment.
Abstract: Sulphur in steel, which is deleterious to its mechanical properties, is reduced in hot metal by external desulphurisation using calcium carbide (CaC2) based reagent at JSW Steel. With an aim of optimising the consumption of this reagent for desulphurisation, sulphur mapping was carried out at different locations, from hot metal production to steel casting, to establish optimum S levels at different stages of hot metal and steel treatment. The performance analysis of plant data for desulphurisation of hot metal shows that the degree of desulphurisation (DS) and hot metal temperature had significant impact on the consumption of reagent. Optimum consumption of desulphurisation reagent is achieved by maintaining hot metal temperature above 1350°C and the DS less than 80%. A computer based model using multiple linear regression techniques has been developed to guide the operator to ensure optimum consumption of desulphurisation reagent.
TL;DR: In this article, an assessment of various methods for calculation of equilibrium slag-metal phosphorous partition for basic oxygen steelmaking in order to select the most acceptable procedure for estimation of the dephosphorisation capability of basic oxygen furnace (BOF) converters at Tata Steel was carried out.
Abstract: The present work carried out an assessment of various methods for calculation of equilibrium slag–metal phosphorous partition for basic oxygen steelmaking in order to select the most acceptable procedure for estimation of the dephosphorisation capability of basic oxygen furnace (BOF) converters at Tata Steel. Equilibrium phosphorous partition was calculated by a thermodynamic approach proposed in the literature using the regular solution based quadratic formalism for slag, by semiempirical equations proposed by some investigators, as well as an optical basicity based correlation reported in literature. Turndown slag and metal composition and temperature data of a large number of BOF heats of LD-1 and LD-2 shops of Tata Steel, covering a period of several years, were employed for this purpose. Large discrepancies between the predictions of empirical correlations proposed by different investigators were found. On the basis of the assessment exercise, the correlation proposed by Turkdogan was accepte...
TL;DR: In this paper, a model to predict the shrinkage and to optimise mold taper for high speed casting is presented by taking into account variations in the TLE of steel and the effect of phase transformation during solidification of steel with varying carbon content.
Abstract: In high speed continuous casting, optimisation of mould taper is important for intensifying heat transfer and improving the quality of cast products. In order to calculate the shrinkage during cooling, the thermal linear expansion coefficient (TLE) model has been developed and combined with phase transformation relevant to continuous casting of steel. In the present paper, a model to predict the shrinkage and to optimise mould taper for high speed casting is presented by taking into account variations in the TLE of steel and the effect of phase transformation during solidification of steel with varying carbon content. The TLE of steel purely from thermal contraction is nearly independent of carbon content when no dRc phase transformation is involved. For example, the TLE of 0 . 05% carbon steel is calculated to be 21 . 3610 26 K 21 , while the TLE of 0 . 60% carbon steel is shown to be 19 . 88610 26 K 21 . However, phase transformation processes which are greatly dependent upon the carbon content account for large difference in the shrinkage behaviour between the various grades of steel and extremely high apparent TLEs are calculated for low carbon steels; for example the apparent TLE for a 0 . 05 wt-%C steel is calculated to be 111 . 81610 26 K 21 .
TL;DR: Stamp charging has been established as a versatile technology which not only improves the coke properties that can be obtained from a given coal blend, but also broadens the coal base for cokemaking, permitting the use of inferior coals without impairing coke quality as discussed by the authors.
Abstract: Stamp charging has been established as a versatile technology which not only improves the coke properties that can be obtained from a given coal blend, but also broadens the coal base for cokemaking, permitting the use of inferior coals without impairing the coke quality. To produce high strength coke at least cost, Tata Steel ventured into stamp charging in combination with 40–45% low ash imported coals. Research carried out by R&D, Tata Steel revealed that stamp charging has the potential power to digest even non-softening carbonaceous inerts, if the coal blend is suitably designed. Addition of such inerts would enhance the carbon content in the resultant coke. However, the use of these inerts calls for judicious selection of other components of the coal blend and optimisation of the blend proportion, or otherwise these inerts may have an adverse impact on the coke quality. Addition of such materials would also contribute to higher coke yield, since the volatile matter contents of these material...
TL;DR: In this article, a comprehensive contour concept of the work roll and its predictive calculation model are put forward to simplify the complex contour curve resulting from superposition of three kinds of contours mentioned above in the online strip shape control model.
Abstract: Initial, thermal and wear contours of the work roll are three major sources of mill disturbance and play critical roles in crown and shape control of strip. To simplify the complex contour curve of the work roll resulting from superposition of three kinds of contour mentioned above in the online strip shape control model, a comprehensive contour concept of the work roll and its predictive calculation model are put forward in the present work. Predictive calculation of the comprehensive contour of the work roll in the online strip shape control model during hot rolling consists of two important parts, namely wear contour calculation and thermal contour calculation, which have a direct influence on the accuracy of shape control. A statistical wear model and a finite difference thermal contour model of the work roll are described in the present work. The comprehensive contour is the sum of grinding, wear and thermal contours. This comprehensive contour calculation model has been applied successfully ...