ISIJ International
New Arrival Alert : OFF

You can use this feature after you logged into the site.
Please click the button below.

Log in / Sign up
ONLINE ISSN: 1347-5460
PRINT ISSN: 0915-1559

ISIJ International Vol. 36 (1996), No. 8

  • Activities in CaO-MgO-Al2O3 Slags and Deoxidation Equilibria of Al, Mg, and Ca

    pp. 983-990

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.983

    The equilibrium experiments between CaO-Al2O3-MgO-0.06 to 0.85%MnO-0.5 to 2.1%FetO-0.07 to 0.3%S (mass content in %) slag and liquid iron were carried out at 1823 and 1873 K in order to assess the activities of Al2O3 and MgO along the spinel (MgO·Al2O3) saturation line. The activities of CaO in an entire liquid region were first determined at 1823 and 1873 K from the reported values for sulfide capacity, coupled with the activity coefficients of CaS which were estimated from those in the CaO-Al2O3 slags. On the basis of these iso-activity lines for CaO, the activities of Al2O3 and MgO were calculated by using he method of Schuhmann, in which the assessed activities of Al2O3 and MgO on the spinel saturation line were taken as the starting points. The activity coefficients of FetO and MnO along the spinel saturation line were determined and the deoxidation equilibria of Al, Mg, and Ca were discussed.
  • Effect of Firing Temperature and Porosity on Thermal Conductivity and Diffusivity of Iron Ore Pellets

    pp. 991-999

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.991

    The thermal diffusivity and conductivity of iron ore pellet were determined by measuring temperature at surface and centre of pellet during heating and applying heat balance. The effect of firing temperature of pellets and its porosity on thermal conductivity were determined. The mineralogical changes on firing were investigated. The results were analysed by applying model equation and on the basis of basic sintering parameters to determine effective thermal conductivity at zero porosity with radial heat transfer.
    x

    Readers Who Read This Article Also Read

    1. Production and Technology of Iron and Steel in Japan during 1991 ISIJ International Vol.32(1992), No.4
    2. Prediction of the Blast Furnace Process by a Mathematical Model ISIJ International Vol.32(1992), No.4
    3. Production and Technology of Iron and Steel in Japan during 1994 ISIJ International Vol.35(1995), No.4
  • Influence of Gaseous Sulfur on CO Reduction of Wustite Added with Foreign Oxides

    pp. 1000-1008

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1000

    Dense wustite plates added separately with major gangues in ironmaking were reduced using a thermobalance at 1173∼1373 K with CO-CO2-COS mixtures to elucidate the cooperative influence of added oxide and gaseous sulfur on the reduction behavior.
    In the tests without sulfur, the reduction was extremely retarded by the existence of Al2O3 or SiO2 in wustite mostly by the formation of dense iron in porous or dense wustite (B or C type), while it was fairly enhanced by adding CaO with porous iron (A type).
    The sulfur addition of PCOS/PCO=2.2×10-6∼2.2×10-5 unable to form oxysulfide liquid resulted in less reduction rates relative to those without sulfur. This action of sulfur was added to an influence exerted by Al2O3 or CaO. When sulfur and CaO coexisted without any oxysulfides, fibrous iron morphology (F type) was strongly realized. At 1373 K the iron morphology became coarser for pure or MgO-doped wustite by adding COS. Regardless of gangues the reduction rates rised with higher temperatures. For the reduction tests of same samples using sulfur-bearing gas, porous iron (A type) was preferred previously in H2, while the present CO reduction conducted mostly dense iron (C type). This is probably because the former gas has a larger oxygen removal force from sulfur-adsorbed wustite surface than the latter one.
    These reduction behavior is discussed focusing a few actions caused by gaseous sulfur.
    x

    Readers Who Read This Article Also Read

    1. Effect of Reducing Gas on the Volume Change during Reduction of Iron Oxide Compacts ISIJ International Vol.36(1996), No.6
    2. Dissolution of Fe2O3 and FeO Pellets in Bath Smelting Slags ISIJ International Vol.32(1992), No.4
    3. Factors Affecting the Sticking of Fine Iron Ores during Fluidized Bed Reduction ISIJ International Vol.32(1992), No.9
  • Thermodynamics of Molten Fe-Cr-Csatd. Alloy

    pp. 1009-1013

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1009

    The activity of chromium in molten Fe-Cr-Csatd. alloy has been measured at temperatures ranging from 1548 to 1773 K by a chemical equilibrium technique. There is little temperature dependence of the activiy of chronium in the region of low chromium contents by weight, and the activity coefficient of chromium decreases as the chromium content increases.
    The activity coefficient of chromium in silver, which was needed for the foregoing measurement, was predetermined.
    By thermodynamic discussion in combination with the carbon solubility in molten iron-chromium alloys, the expression for the activity coefficient of chromium in Fe-Cr-Csatd. alloy has been obtained as a function of chromium content and temperature as follows.

    lnγCr(s)= -2.52+T3880 +(8.31-T23300)XCr+(-4.21+T14900)XCr2 (1623 to 1773K)

    The standard Gibbs energy of mixing of Fe-Cr-Csatd. alloy was also estimated using the Gibbs-Duhem relationship, indicating that chromium and manganese behave similarly in terms of affinity for carbon and iron in molten carbon-saturated iron.
  • Effect of S Content on the MnS Precipitation in Steel with Oxide Nuclei

    pp. 1014-1021

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1014

    Manganese sulphide formation experiments were carried out by deoxidizing with various elements and by changing S content to clarify the effect of S content n the MnS precipitation with various kinds of oxide nuclei. The behabvior of MnS precipitation on oxide particles in the steel with 1 mass% of Mn was characterized according to S content. When S content was below 100 ppm, a lot of MnS precipitated only on some kinds of oxide. It is effective to use an oxide having high sulphide capacity and low melting temperature for uniform dispersion of fine MnS. On the other hand, when S was above 100 ppm, almost all the oxides worked as the precipitation sites of MnS. In that case, for the MnS dispersion, it is better to select the oxide which tends to disperse finely itself in steel. The average diameter of MnS, calculated by using a mathematical model considering the oxide nuclei with changing the precipitation ratio according to S content and to the kind of oxides, agrees well with the experimental data.
  • Application of Solidification Theory with Small-supercooling to Morphology of Dendritic Inclusions in Steel

    pp. 1022-1029

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1022

    Tip shape of dendritic Type II manganese-sulfide is analysed based on the supercooling solidification theory which Lipton et al. proposed. The theory is derived from the marginal stability of dendrite tip, and needs several physical parameters and constants which are not necessarily known accurately for manganese-sulfide/enriched melt interface. The authors' approach took rough assessment to the figures of physical properties, but the results of calculation give a confidence to a theoretical method of evaluating tip radius of the inclusions.
  • The Analysis of Molten Steel Flow in Billet Continuous Casting Mold

    pp. 1030-1035

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1030

    In this study, the main objective is to develop a mathematical model to simulate the flow behavior of molten steel in billet continuous casting mold. The results can aid the actual operation in continuous casting process.
    In order to understand the flow behavior of moten steel in casting mold, a mathematical model based on SOLA1) method has been developed to analyze the three dimensional turbulent flow conditions. The flow pattern in the casting mold can be described by the analysis and the effects of submerged nozzle design and operating conditions on the flow behavior can be evaluated. The efficiency rate of nonmetallic inclusion removal can be also estimated.
  • Characteristics of Pulsed Current Bead on Plate Deposit in Flux Cored GMAW Process

    pp. 1036-1045

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1036

    The influences of pulse parameters, arc voltage and welding speed on the characteristics of weld beads deposited on C-Mn steel plate by flux cored GMAW process have been studied. The pulse parameters are found to affect the microstructure and porosity content of weld bead and the width of HAZ. The arc voltage, affecting the lp, and lb, also found to influence the characteristics of weld bead significantly. The porosity content of weld bead and the width and hardness of HAZ are found to have a significant correlationship with a factor, defined as a function of lp, lb, f and tb. The influence of welding speed has been found of usual nature. It is marked that a right selection of pulse parameters can improve the weld quality over that observed in case of continuous current GMAW.
  • Recrystallisation of Ti IF Steel Investigated with Electron Backscattering Pattern (EBSP)

    pp. 1046-1054

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1046

    The deformed structure of cold rolled IF steels consists of a large number of α fibre and γ fibre oriented grains and a small number of (110)<110> oriented grains, each with a distinctive grain shape, subgrain structure, hardness and etching appearance. Early nucleation occurs mainly in γ fibre grains and (110)<110> grains. The texture of the early nuclei consists of a γ fibre with a spread towards (221)<110> together with a weak <100>// ND fibre. Numerous nuclei develop within a single deformed grain. α fibre grains are consumed only after 70% of the materials is recrystallised.
  • Effect of Large Particles and Fine Precipitates on Recrystallization and Transformation Behaviour of Ti Treated Low Carbon TiO Steel

    pp. 1055-1062

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1055

    Austenite recrystallization and ferrite transformation behaviour of a Ti treated low carbon TiO steel was studied by uniaxial hot compression in a temperature range of 780 to 1300°C. The results have been compared to that of a conventional TiN steel. It was found that large oxide particles present in TiO teel have shown ability to stimulate recrystallization nucleation and transformation during deformation but failed to accelerate recrystallization of bulk material because of an insufficient volume fraction of these large particles in the steel. The influence of Ti: N ratio in TiO steel is critical to TiN precipitation behaviour which affects microstructural development during thermomechanical processing. TiN precipitates in TiO steel are coarser in comparison to conventional Ti microalloyed steel thus reducing grain boundary pinning effects. It was also found that recrystallization of ferrite in cold worked TiO and TiN steels was not affected significantly by large particles and fine precipitates but controlled by pearlite size and distribution.
  • Influence of Alloying Elements in Solution on Static Recrystallization Kinetics of Hot Deformed Steels

    pp. 1063-1069

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1063

    Using torsion tests and applying the back extrapolation method, a study has been made of the influence on static recrystallization kinetics of the most common elements (C, Si, Mn, Mo) in low alloy steels and the most common elements (Ti, V, Nb) in microalloyed steels. In the latter case, this influence is studied only at the temperatures at which these elements are in solution, except for Titanium which was partially precipitated in the form of nitrides. Activation energy is the parameter most sensitive to variations in the chemical composition and an expression has been determined to predict its value as a function of the content of each alloying element. Of the different non precipitate-forming alloys sillicon is shown to be the element which most delays recrystallization. Carbon and vanadium in solution have no influence on recrystallization kinetics. It is demonstrated that Nb is the microalloying element which most delays recrystallization.
  • Static Recrystallization Modelling of Hot Deformed Steels Containing Severl Alloying Elements

    pp. 1070-1076

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1070

    Using torsion tests a model has been constructed to predict the recrystallized fraction of deformed austenite in low alloy and microalloyed steels. The model quantifies the influence of the most common elements (C, Si, Mn, Mo) in low alloy steels and the typical elements (Ti, V, Nb) in microalloyed steels in the recrystallized fraction, when they are in solution. Static recrystallization kinetics follow Avrami's law and expressions for the parameter t0.5 and for the exponent n are not given. The values predicted by the model are compared with the experimental values, good concordance being obtained between both.
    x

    Readers Who Read This Article Also Read

    1. Effect of Alloying Nitrogen on Crevice Corrosion of Austenitic Stainless Steels ISIJ International Vol.36(1996), No.7
    2. Phase Transformations in Two C–Mn–Si–Cr Dual Phase Steels ISIJ International Vol.46(2006), No.10
  • Static Recrystallization Modelling of Hot Deformed Microlloyed Steels at Temperatures below the Critical Temperature

    pp. 1077-1083

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1077

    Using torsion tests and applying the back extrapolation method a model has been constructed to predict the recrystallized fraction of deformed austenite in Nb, V and Ti microalloyed steels at temperatures below the temperature at which the inhibition of recrystallization commences due to induced precipitation, This temperature, named static recrystallization critical temperature, is modelled as a function of grain size, strain and the solubility temperature. A discussion is made of the importance of being able to predict SRCT in order to effectively apply the model of static recrystallization at temperatures both above and below it. It is demonstrated that Niobium precipitates delay the recrystallization most.
  • Static Recrystallization of Nb and Nb-B Steels under Continuous Cooling Conditions

    pp. 1084-1093

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1084

    The recrystallization behaviour of nine steels containing various combinations of Mo, Nb and B was investigated under continuous cooling conditions. Hot torsion tests were performed using a 17 pass deformation schedule at strain rates of 0.2 to 10 s-1 and interpass times of 1 to 150 s. After rehating at 1250 or 1200°C, the first deformation was applied at 1180°C and the last one at about 700°C. By plotting mean flow stress vs. 1000/T, the no-recrystallization temperatures (Tnr) were determined, and the effects of chemical composition and deformation conditions were assessed. Separate empirical equations for the Tnr were derived from the data for short and long interpass times. These relations describe the influence of chemical composition and of the pass strain, strain rate, and interpass time under continuous cooling conditions. Furthermore, the relationship between the residual strain εr or the residual strain ratio λ and the deformation parameters was also established by analyzing the flow curves. This made it possible to specify the recrystallization limit temperatures (RLT) and recrystallization stop temperatures (RST) that apply to each steel and to each combination of rolling conditions.
    x

    Readers Who Read This Article Also Read

    1. Mathematical Modeling of Mean Flow Stress during the Hot Strip Rolling of Nb Steels ISIJ International Vol.36(1996), No.12
  • Modellong the Evolution of the Microstructure of a Nb Steel

    pp. 1094-1102

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1094

    A mathematical model, for the prediction of the evolution of the microstructure during hot forming of microalloyed steels, is presented. The material behavior is combined with a finite-element model of the deformation. Multi-stage, isothermal compression tests are used for verification. The effect of the interruption between stages of compression on the restoration mechanisms is studied in three-stage tests. The influence of the deformation history on the microstuctural development and on the softening mechanisms is also analyzed. The distribution of austenite grain sizes is predicted. The inhomogeneity of the resulting structure is connected to that of the mechanical attributes of the deformed material. The studies show that additional grain refinement can be expected by controlling the recrystallization kinetics and the retained strain.
  • Formation of Surface Texture and Anisotropy of Shape Memory Effect in an Fe-Mn-Si Alloy

    pp. 1103-1108

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1103

    Formation of surace texture and its influence on shape memory effect in an Fe-Mn-Si alloy have been investigated, using specimens taken from the surface layer and from the central layer of the hot rolled sheet produced using a low-tempperature finishing. It was found that a shear texture with a major component of {001}<110> was formed in the surface layer of the sheet, resulting in a marked anisotropy of shape recovery strain, while a pure metal type rolling texture was formed in the mid-thickness, leading to a less anisotropy. A maximum of shape recovery strain at a given prestrain is obtained for the specimens with tensile axes parallel to the rolling direction (RD) or the transverse direction to the RD in the plane of the surface layer, i.e. the specimens with their tensile axes preferentially oriented to <110>. This suggests the possibility of improvement in shape memory effect of the whole sheet by a further spreading if the surface texture towards the central layer of the sheet if the rolling process is optimized.
  • Note Differential Thermal Analysis of Assimilation and Melt-formation Phenomena in the Sintering Process of Iron Ores

    pp. 1109-1111

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2355/isijinternational.36.1109

    x

    Readers Who Read This Article Also Read

    1. Production and Technology of Iron and Steel in Japan during 1991 ISIJ International Vol.32(1992), No.4
    2. Prediction of the Blast Furnace Process by a Mathematical Model ISIJ International Vol.32(1992), No.4
    3. Production and Technology of Iron and Steel in Japan during 1994 ISIJ International Vol.35(1995), No.4

Article Access Ranking

21 Jan. (Last 30 Days)

  1. Heat Transfer Characteristic of Slit Nozzle Impingement on High-temperature Plate Surface ISIJ International Advance Publication
  2. Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies Tetsu-to-Hagané Vol.105(2019), No.1
  3. Effects of Impurities and Processing Conditions in Al–1%Mn Alloys on the Formation of Thermally Stabilized Substructures MATERIALS TRANSACTIONS Vol.59(2018), No.11
  4. Fusion Zone Microstructural Evolution of Al-10% Si Coated Hot Stamping Steel during Laser Welding ISIJ International Vol.59(2019), No.1
  5. A Review of the Chemistry, Structure and Formation Conditions of Silico-Ferrite of Calcium and Aluminum (‘SFCA’) Phases ISIJ International Vol.58(2018), No.12
  6. Effects of Sulfur and Titanium Interaction in Molten Pig Iron on Erosion of Carbon Brick ISIJ International Vol.59(2019), No.1
  7. Recent Progress on Advanced Blast Furnace Mathematical Models Based on Discrete Method ISIJ International Vol.54(2014), No.7
  8. Preface to the Special Topics Entitled “To Solve Problems of Hot Rolling Rolls” Tetsu-to-Hagané Vol.104(2018), No.12
  9. Effect of Annealing Time on Oxides Phases and Morphology along Oxidized Depth of Fe-3%Si Steel during Decarburization ISIJ International Vol.59(2019), No.1
  10. Preparation of High-Carbon Metallic Briquette for Blast Furnace Application ISIJ International Vol.59(2019), No.1

Search Phrase Ranking

21 Jan. (Last 30 Days)

  1. blast furnace
  2. blast furnace productivity
  3. blast furnace permeability
  4. 鉄と鋼
  5. laser welder
  6. titanium
  7. activity feo
  8. argon steel
  9. eaf operation
  10. electric arc furnace