Steel Science Portal

Tetsu-to-Hagané
New Arrival Alert : OFF

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

Log in / Sign up

Grid List Abstracts

ONLINE ISSN: 1883-2954
PRINT ISSN: 0021-1575

Tetsu-to-Hagané Vol. 83 (1997), No. 3

  • Analytical Research for the Improvement in Iron Ore Sintering Mechanism with the Design of Pseudo-particles

    Tetsuzo HAGA, Akiyoshi OHSHIO, Shunji KASAMA

    pp. 169-174

    Bookmark

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

    Log in / Sign Up

    Abstract

    Several pretreatment methods of raw mix have been proposed to improve sintering reaction, such as, melting reaction of fine iron ores with limestone fines, assimilating reaction of coarse iron ores with the melt, and so on. For optimizing these pretreatment processes, it is important to clarify the effect of the structure of sinter mix pseudo-particles made by these processes on the sintering mechanism including the permeability during sintering and the combustion efficiency of coke breeze in sintering bed.
    In this study, analytical research was carried out for evaluating the change in the sintering mechanism with some pretreatment methods of raw mix, i.e. the ordinary granulation [a], the high moisture granulation [b] and the fine part selective granulation method of clayish iron ores ([c] : with limestone, [d] : without limestone). Characteristics of sinter mix pseudo-particles were investigated and sintering pot tests were carried out under these pretreatment methods.
    Permeability of packed bed was improved with increase in 2-5mm even-sized pseudo-particles. For increasing the amount of coke combustion (CO+CO2), it was also effective to concentrate coke breeze at the surface of pseudoparticles. The complete combustion rate of coke (CO2/(CO+CO2)) was improved with limestone concentration at the surface of pseudo-particles as case [d].
    Though sintering speed was improved with these intensified granulating process [b], [c] and [d], the strength of sinter was decreased due to increasing in the cooling rate of sinter in the case of high moisture granulation [b]. By contrast, in case of the selective granulation [c] and [d], the strength of sinter was improved due to the increase in melt formation and the decrease of cooling rate of sinter.

    Recommended Articles: Development of Evaluation Method for Softening-melting Properties of Sinter [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Development of Evaluation Method for Softening-melting Properties of Sinter Tetsu-to-Hagané Vol.83(1997), No.2
    2. Improvement of the Melting Reaction in Sintering Process by the Fine Part Selective Granulation of Clayish Iron Ores Tetsu-to-Hagané Vol.83(1997), No.4
    3. Control Technique of the Melting Reaction in Sintering Process by the Fine Part Selective Granulation of Clayish Iron Ores Tetsu-to-Hagané Vol.83(1997), No.2

  • Desulfurization of Direct-reduced Iron Produced by Heating Iron-ore/Carbon Composite Pellet with Hydrogen and Hydrogen/Water-vapor Gas Mixture

    Haruhiko SAKAMOTO, Yoshiaki IGUCHI, Shoji HAYASHI

    pp. 175-180

    Bookmark

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

    Log in / Sign Up

    Abstract

    The direct-reduced iron produced from iron-ore/coal composite pellet is generally contaminated with sulfur. In this study, iron-ore/coal composite pellet is partially or completely reduced during heating up to given temperatures, 1173 to 1473K, at a constant rate in nitrogen atmosphere. Subsequently, it is treated with H2-H2O, H2, or CO-CO2 gas mixtures to complete reduction and to perform desulfurization. It is shown that hydrogen treatment is effective to remove the sulfur and water-vapor addition to hydrogen can further enhance the desulfurization kinetically and thermodynamically. The desulfurization rate is very fast and is mainly controlled by chemical reaction on the pore surface of reduced iron. On the other hand, to treat it with a CO-CO2 gas mixture is almost invalid to desulfurization.

    Recommended Articles: Development of Injection Lance with High Combustibility for High Rate Coal Injection [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Development of Injection Lance with High Combustibility for High Rate Coal Injection Tetsu-to-Hagané Vol.84(1998), No.1
    2. The Reduction and Melting Behavior of Carbon Composite Iron Ore Pellet on High Temperature Tetsu-to-Hagané Vol.84(1998), No.6
    3. Combustion and Gaification Reaction Behaviors of Plastic in Blast Furnace Tetsu-to-Hagané Vol.83(1997), No.9

  • Influence of Sample Shape on Ion Beam Current in Analysis of Fe-based Alloy by Glow Discharge Mass Spectrometry

    Noriko OKAMOTO, Takashi SAKA, Masanao NARITA

    pp. 181-186

    Bookmark

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

    Log in / Sign Up

    Abstract

    For the analysis of trace elemental constituents by glow discharge mass spectrometry, ion beam ratios (IBRs), ratios of ion currents of analysed elements to that of matrix element, are observed. In general, IBRs are affected by the shape for pin-shaped samples or the size of mask for disk-shaped samples. These effects were studied systematically for Febased alloys. For disk-shaped samples, IBRs are rather independent of the mask size provided that the diameter is in the range of 10-15mm. For pin-shaped samples, IBRs depend on the sample shape. However, it has been shown that IBRs for arbitrary shapes can be corrected to that of a standard shape using an experimental equation. The equation for correction is a linear combination of r, L and L2 and F, where r and L are diameter and discharge length of pin-shaped samples, respectively, and F is a parameter for the shape of cross section. IBRs depend on r linearly. On the other hand, they are dependent on the second order of L. The fact indicates that there exists a discharge length (Lext) for each element giving the IBR an extremum. LextS are 3-6mm for the most elements. By using sample whose discharge length is close to Lext, it is possible to minimize the effect of discharge length on IBRS. The present correction shows the possibility to reduce the coefficient of variation for samples of arbitrary shapes from 40% to less than 10%.

  • Isolation and Identification of Dross Precipitated in 55mass% Al-Zn Bath

    Kyoko FUJIMOTO, Makoto SHIMURA, Keiichi YOSHIOKA, Yoshiko FUNAHASHI

    pp. 187-192

    Bookmark

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

    Log in / Sign Up

    Abstract

    Based on studies of the electrochemical stability of the intermetallic compound (Al-Fe-Si-Zn) in a 55mass% Al-Zn bath, a method of isolating and identifying the composition of the dross was established.
    The dross was extracted by controlled potential electrolysis at-1.4V vs. SCE in a 10mass% NaOH solution. A small amount of residual Zn was removed by dissolving with concentrated HNO3. The extracted dross was dissolved in HCl and the amounts of Al, Fe, Si and Zn were determined by ICP-AES. The concentration and chemical composition of the dross in rapid-cooled and air-cooled samples were almost equivalent.
    The method of controlled potential electrolysis in an NaOH solution was also found to be applicable to the removal of the upper layer of 55mass% Al-Zn plate for electron microscope observation of the alloyed layer (Al-Fe-Zn-Si intermetallic compounds).

  • Relative Sensitivity Factors for Fe-based and Ni-based Alloys in Glow Discharge Mass Spectrometry

    Noriko OKAMOTO, Takashi SAKA, Masanao NARITA

    pp. 193-198

    Bookmark

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

    Log in / Sign Up

    Abstract

    Relative sensitivity factors (RSFs) in the analysis of glow discharge mass spectrometry were determined for Fe-based and Ni-based alloys. From 12 Fe-based alloys and 15 Ni-based alloys, pin-shaped and disk-shaped samples were prepared. RSFs of 42 elements in Fe-based alloys and 35 elements in Ni-based alloys were determined using both pin-shaped and disk-shaped samples. The effect of the matrix on RSFs is not recognized. The values of RSFs agree quite well with previous work. However, a systematic deviation of the values of RSFs has been recognized between pin-shaped and disk-shaped samples. This deviation is expressed well by a linear relation. RSFs for disk-shaped samples are obtainable from those for pin-shaped samples using the linear relation and vice versa.

  • Effect of Intermediate Layer of Diffusion Barrier on Tensile Strength of Brazed Joint of Stainless Steel Coated with Ni-Cr-B Alloy Filler

    Tomoaki HYODO, Tetsuro TOYODA, Hiroshi KIBE, Junichi KOZAKI, Makoto KABASAWA, Manabu TAMURA

    pp. 199-204

    Bookmark

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

    Log in / Sign Up

    Abstract

    An aluminum oxide (Al oxide) intermediate layer was applied as an diffusion barrier to the brazing of a stainless steel using a filler of evaporated nickel-chromium-boron alloy (Ni-Cr-B) film. When the diffusion barrier was not applied, the tensile strength of the brazed joint of a Ni-Cr-B filler coated steel was increased as the filler thickness increased from 7μm to 10μm. On the other hand, a Ni-Cr-B filler of less than 7μm thickness was almost ineffective in increasing the tensile strength of joints without the diffusion barrier. It is presumed that Ni and B in the filler metal diffused into the substrate during the thermal cycle for brazing, and this raised the liquidus temperature of the filler metal to a temperature above the brazing temperature. An intermediate layer of Al oxide was effective in reducing the diffusion of Ni and B in the filler into the substrate. Hence it increased the tensile strength of the brazed joint. The brazed joint of the steel plated with Ni-Cr-B/Al oxide double layers showed sufficient tensile strength when used in an automobile metal honeycomb catalyser.

  • Phase Transformation of Al2O3 Scales Formed on Al-deposited Fe-Cr-Al Alloy Foil

    Atsushi ANDOH, Shigeji TANIGUCHI, Toshio SHIBATA

    pp. 205-210

    Bookmark

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

    Log in / Sign Up

    Abstract

    The phase transformation of Al2O3 formed on an Al-deposited Fe-Cr-Al alloy foil and an Fe-20Cr-5Al alloy foil of the similar composition, and their oxidation kinetics have been studied in air at 1073-1373K using XRD, SEM and SIMS.
    It was found that the deposition of Al promotes the growth of metastable aluminas. The transformation of metastable Al2O3 to α-Al2O3 formed on the Al-deposited foil is slower than that on the alloy foil. The values of kp for the growth of α-Al2O3 on the Al-deposited foil is smaller than that on the alloy foil in the temperature range 1273 to 1373K. These are attributable to the purity of the Al2O3 initially formed on Al-deposited foil.
    The phase transformation of Al2O3 is reflected by the scale morphology. The nucleation of θ-Al2O3 occurs on the surface of granular γ-Al2O3. θ-Al2O3 having a shape of whisker grows on the oxide surface. The morphology of whiskers is more round, after θ-Al2O3 transforms to α-Al2O3. We obtained the TTT diagrams for the phase transformation of Al2O3 scales formed on both foils in air in the temperature range 1073 to 1373K.

  • Effect of Retained Martensite on High Temperature Deformation of SUS304 with a Fine Grain Size

    Masahito KATO, Yasunori TORISAKA

    pp. 211-214

    Bookmark

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

    Log in / Sign Up

    Abstract

    The high temperature deformation properties of two stainless steels, austenite single phase and austenite/martensite dual phases have been studied. These two materials were not conventionally produced but reversely transformed into austenite phase from martensite phase which was induced by large plastic deformation on austenitic stainless steel SUS304 (similar to AISI304) below the temperature of Md point.
    Tensile tests on both alloy sheets with initial grainsize refined below 1μm by such above processing have been conducted at different temperatures from 923K to 1023K at strain rates ranging from 3.0 × 10-5to 1.0 × 10-2 s-1. These both materials exhibit a maximum elongation exceeding 200 pct with very low flow stress. The dual phase material shows more elongation and less flow stress in comparison with the single phase material, and the lower testing temperatures or the higher strain rates, the larger this tendancy becomes clearly. This is the reason why a slight martensite phase which is included in the dual phase material prevents the grain size of austenite phase from coasening during large deformation.

  • Effect of P and C Segregation and Grain Size on Bending Strength of the Carburized and Induction Hardened Steel

    Nobuhiro MURAI, Toru TAKAYAMA, Masahiro ARAI, Yoshihiko KAMADA, Mitsuo UNO, Kazuyuki ORITA, Takashi MASAKI, Yukio ARIMI, Akira MUTAGAMI

    pp. 215-220

    Bookmark

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

    Log in / Sign Up

    Abstract

    In order to increase the bending strength of automotive differential gears, a new heat treatment, where induction hardening is carried out after carburizing, was studied. The bending test specimens of a modified JIS SCM822 grade were gas-carburized, followed by quenching, induction hardening and low-temperature-tempering.
    Induction hardening after carburizing prevented intergranular fracture of the case. The results of Auger electron spectroscopy showed that induction heating decreased the phosphorus and carbon segregation at the austenite grain boundaries, which is the cause of the case intergranular embrittlement of carburized steels. The calculation of the diffusion distance indicated that the duration of the induction heating was too short for phosphorus and carbon to resegregate fully to the austenite grain boundaries which were reproduced during the heating.
    Such reduction in segregation and the austenite grain refinement in the case of the carburized and induction hardened steel increased the bending strength by the amount of 36 per cent.

    Recommended Articles: Estimation of Delayed Fracture Property of Steels [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Estimation of Delayed Fracture Property of Steels Tetsu-to-Hagané Vol.79(1993), No.2
    2. Evaluation Method of Delayed Fracture Property of High Strength Steels Tetsu-to-Hagané Vol.83(1997), No.7

  • Influence of Ti and N on Strength and Toughness of 780MPa Class Steels and Their Simulated HAZ Toughness

    Toshiei HASEGAWA, Yukio TOMITA

    pp. 221-226

    Bookmark

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

    Log in / Sign Up

    Abstract

    Influence of Ti and N on strength and toughness of base plate and HAZ in 780MPa class steels with ultra-heavy thickness of over 150mm was examined using a thermal-cycle simulator.
    (1) Relationship between Ti content and mechanical properties of the base plate under as-quenched condition varies depending on N content. While, toughness of medium-N steels (N = 40ppm) is improved by adding Ti due to microstructural change, toughness of low-N steels (N = 20ppm) deteriorates with increasing Ti content due to precipitation hardening by TiC.
    (2) Influence of Ti and N on simulated HAZ toughness is more significant for double cycle condition than that for single cycle. Ti addition gives remarkable improvement in simulated HAZ toughness of the medium-N steels for double cycle condition. On the other hand, simulated HAZ toughness of the low-N steels deteriorates with increasing Ti content. The governing factors of the simulated HAZ toughness in double-cycle condition are the same as those of the toughness of base plate.
    (3) It is concluded that the low-N steel without Ti addition and medium-N steels with Ti addition of 0.005 0.01% attain both high simulated HAZ toughness and high strength and toughness of base plate.

    Recommended Articles: Precipitation Behaviour of Titanium Carbo-sulfide in Extra-low-carbon Titanium-added Steels [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Precipitation Behaviour of Titanium Carbo-sulfide in Extra-low-carbon Titanium-added Steels Tetsu-to-Hagané Vol.81(1995), No.3
    2. Strengthening Mechanisms of Ti and Nb Bearing Steel Plates Produced by Thermomechanical Control Process Tetsu-to-Hagané Vol.82(1996), No.6
    3. Analysis of Precipitates and Precipitation Behavior in Nb-Ti Bearing Steels Tetsu-to-Hagané Vol.82(1996), No.2

  • Influences of Microstructures of Fatigue Strength of Medium Carbon Microalloyed Steels

    Ichie NONIURA

    pp. 227-232

    Bookmark

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

    Log in / Sign Up

    Abstract

    Influences of the microstructures on the fatigue properties of the medium carbon microalloyed steels were investigated under the rotating bending fatigue tests. Results obtained are as follows: (1) Under fatigue conditions surface relief made of slip bands are found to be generated largely on ferrite in the medium carbon ferrite pearlite steels. The fatigue crack initiates along the surface relief and propagates along the ferrite/pearlite boundary in the early stage of the fatigue crack propagation. (2) Increase in vanadium contents raises the slip band initiation stress and the fatigue strength through strengthening ferrite. Increase in carbon or manganese contents raises the fatigue strength through increasing pearlite volume fraction and refining ferrite grain size. Increase in vanadium contents are more effective to improve the fatigue limit ratio. (3) Coarsening of prior austenite grain size reduces the fatigue limit. This is because the ferrite precipitated along austenite grain boundary are regarded as small fatigue cracks in medium carbon ferrite pearlite steels with fine prior austenite grain size.

    Recommended Articles: Magnetic Properties of Fe-Cr-C and Fe-Cr-C-Ni Alloys [ View more ]

    x

    Readers Who Read This Article Also Read

    1. Magnetic Properties of Fe-Cr-C and Fe-Cr-C-Ni Alloys Tetsu-to-Hagané Vol.88(2002), No.4
    2. Wear Resistance and Resistance to Surface Roughening of Newly Developed Material for Piercing Roll with High Carbon and Low Hardness Tetsu-to-Hagané Vol.89(2003), No.5
    3. Morphology Control of Zinc Deposits of Electrogalvanized Steel Sheets Tetsu-to-Hagané Vol.88(2002), No.5
  • © 1997 The Iron and Steel Institute of Japan

Article Access Ranking

28 Jan. (Last 30 Days)

  1. Perspective toward Long-term Global Goal for Carbon Dioxide Mitigation in Steel Industry Tetsu-to-Hagané Vol.105(2019), No.6
  2. Review on the High-Temperature Thermophysical Properties of Continuous Casting Mold Fluxes for Highly Alloyed Steels Tetsu-to-Hagané Vol.107(2021), No.1
  3. Quantitative Evaluation of Solute Hydrogen Effect on Dislocation Density in a Low-carbon Stable Austenitic Stainless Steel ISIJ International Advance Publication
  4. In-Situ Observation Experimental Study on the Agglomeration and Dispersion of Particles at the Interface of High-temperature Melts ISIJ International Advance Publication
  5. Development and Prospects of Refining Techniques in Steelmaking Process ISIJ International Vol.60(2020), No.12
  6. Improved Hydrogen Embrittlement Resistance of Steel by Shot Peening and Subsequent Low-temperature Annealing ISIJ International Advance Publication
  7. Effects of Stress and Plastic Strain on Hydrogen Embrittlement Fracture of a U-bent Martensitic Steel Sheet ISIJ International Advance Publication
  8. In situ Observation of Reduction Behavior of Multicomponent Calcium Ferrites by XRD and XAFS Tetsu-to-Hagané Advance Publication
  9. Preface to the Diamond Jubilee Issue on “Selected Topics in Iron and Steel and Their Processing toward the New Steel Age” ISIJ International Vol.60(2020), No.12
  10. Intraparticle Temperature of Iron-Oxide Pellet during the Reduction Tetsu-to-Hagané Vol.60(1974), No.9

Search Phrase Ranking

28 Jan. (Last 30 Days)

  1. blast furnace
  2. 西山記念技術講座
  3. blast furnace permeability
  4. blast furnace burden distribution
  5. blast furnace productivity
  6. j. f. elliott
  7. lme
  8. weld gas backing
  9. bottom dross
  10. carbon-containing pellet