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

Tetsu-to-Hagané Vol. 59 (1973), No. 14

  • 社会的責任と研究開発

    pp. 1877-1878

    Bookmark

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

    Log in / Sign Up
  • Reduction of Iron Oxide Pellets with Hydrogen in Non-isothermal Moving Bed

    pp. 1879-1887

    Bookmark

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

    Log in / Sign Up
    A mathematical model for non-isothermal countercurrent moving bed was proposed and one of the numerical calculation methods was developed. The expression for the reaction rate included in this model was based on the unreacted core model, and the rate parameters were determined by using experimentally obtained rates of the reduction of single iron oxide pellet by hydrogen.
    The influence of the operating conditions on process variables in the bed was analyzed theoretically. At the same time, the experiments of non-isothermal countercurrent moving bed were carried out and the experimental results were compared with the calculated results. It was found that calculated values agree well with those obtained experimentally.
    The results were summarized as follows:
    1) The proposed mathematical model was most suitable for the analysis of the obtained result.
    2) It was found that the rate parameters measured from single iron oxide pellet could for the process-analysis of moving bed.
    3) The longitudinal distributions of process variables in non-isothermal countercurrent moving bed cold be estimated with considerable accuracy.
  • Study on the Rate of Reduction of Single Iron Oxide Pellet with Hydrogen

    pp. 1888-1901

    Bookmark

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

    Log in / Sign Up
    An equation for the rate of reduction of a hematite pellet is derived based on an unreacted-core shrinking model, considering the resistance due to the mass b alance of reactions. Then, a modified diffusion coefficient, D′H2-H2O, of H2 gas in ternary gas system, H2-H2O-N2, is derived considering the influence of stagnant N2 gas. The estimation methods for the viscosity and diffusion coefficients or equiliblium constants are also described in view of the best agreement with experimental values.
    Using these results, the above mentioned equation and experiment al data of TAKAHASHI, et al. and FEINMAN, et al., calculation is carried out by the method offered by YAGI and ONO, then the reasonable values of effective diffusion coefficient through the porous shell of reduced pellet and chemical reaction constants are obtained. On the other hand reduction rate equation without the resistance due to the mass balance gives unsatisfactory results. Consequently, it becomes clear that consideration of this resistance is rather reasonable and necessary.
  • Kinetic Study of the Rate of Reduction of Single Iron Oxide Pellet under Pulsating Flow

    pp. 1902-1913

    Bookmark

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

    Log in / Sign Up
    The fact that the rate of reduction of a hematite pellet under pulsating flow is higher than that under steady flow can de ascribed to the decrease of mass-transfer resistance in the gas film. The rate of reduction under pulsating flow is calculated by the use of an unreacted-core shrinking model and KITAURA'S expression for a mass-transfer coefficient, and the following conclusions are obtained.
    (1) The rate of reduction under pulsating flow increases as frequency and amplitude of pulsation increase.
    (2) Pulsating flow accelerates the reduction effectively especially in the early stage of reduction and in a high temperature range. This trend coincides qualitatively with previously reported results.
    (3) Optimum values of the pellet diameter and time-averaged flow rate are proposed.
    (4) When the pellet diameter and flow rate are not signiffcantly large, the effect of pulsating flow increases gradually as N2 gas percentage in binary bulk gas, H2-N2, increases.
  • On the Nitrogen Absorption of Liquid Iron Accompanying Carbon-Oxygen Reaction

    pp. 1914-1924

    Bookmark

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

    Log in / Sign Up
    The effect of carbon-oxygen reactions on the rate of nitrogen absorption in liquid iron were studied under N2-O2 and N2-CO2 gas mixtures.
    It was confirmed that the experimental results on the decarburization of liquid iron agreed well with those obtained by several investigators.
    On the other hand, the simultaneous absorption of nitrogen in liquid iron shows a peculiar behavior as compared with the absorption without carbon -oxygen reaction at the interface. Namely, it was observed that the nitrogen concentration in liquid iron does not reach to equilibrium with nitrog en partial pressure in bulk gas phase, although the rate of nitrogen absorption in the initial period is rather rapid. This may be resulted from the decrease of nitrogen partial pressure at g as-metal interface due to the evolution of carbon monoxide from liquid iron. In this case, the nitrogen absorption may be controlled mainly by the transfer of nitrogen in liquid iron and also in gas phase.
    When the oxygen concentration of gas phase becomes nearly 30 percent, the effect of the absorbed oxygen at the gas-metal interface becomes more predominant in nitrogen absorption than that of d ecrease of nitrogen partial pressure at interface. When liquid iron contains sulphur, the effect of the adsorbed sulphur at the interface may also be predominant similarly to the case of 30% O2-N2 gasmixture.
  • Production and Properties of Twin Billet by a Continuous Casting Machine with Reduction Mill

    pp. 1925-1933

    Bookmark

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

    Log in / Sign Up
    The tests to produce two 75 mm square billets from twin-billet, to which a 120 mm square cast billet is rolled by one pass, were carried out by an in-line reduction mill installed in a continuous casting machine. The produced billet is further hot-deformed to square or round bars in order to study the material properties and strength.
    The results obtained are as follows:
    1. No crack was observed even after high reduction since sufficiently high temperature is maintained in the core of the billet during reduction process. The deformation resistance is as small as 5 to 6 kg/mm2.
    2. The center porosity and other defects in the central part of the bar which were previously rolled from the twin billet can be completely eliminated, because the central part of the cast billet is deformed into the joint of the twin billet in the process of in-line reduction.
    3. The surface of the bars at the joint of the twin billet shows a macro structure with a unique pattern which, however, diminishes by raising the rolling reduction ratio. The mechanical strength of the joint is found to be the same level as the other part for both low and medium carbon steels.
    But for a high carbon steel, the strength of the joint is lower than the other part.
  • Effect of Titanium on the Microstructure of 15Cr-14Ni Heat Resisting Steels

    pp. 1934-1947

    Bookmark

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

    Log in / Sign Up
    The microstructures and hardness of 15Cr-14Ni-Ti type heat resisting steels aftersolution and aging treatments were investigated in order to obtain some information for the development of a high strength heat resisting steel.
    It was found that the hardness of the steels increased with increasing titanium content and with decreasing the solution temperature. This is due to the dispersion hardening caused by undissolved. titanium carbide particles, as explained by Orowan's by-pass process.
    The solubilities of carbon and titanium carbide at solution treatment temperature were determined for some steels and the result indicated that these solubilities decreased with increasing titanium content.
    The diameter of undissolved carbide particle increased with increasing titanium content and with increasing solution temperature. The dispersion density of these particles, which showed the maximum value at 0.36%Ti, decreased with increasing the solution temperature.
    The chronological change of chromium and titanium carbides precipitated during heating was observed morphologically. Coarsening of cubic M23C6 carbide during aging was interpreted by Lifshitz-Wagner theory, and was controlled by the diffusion of chromium. The precipitation hardening in the investigated steels was attributed to the dispersion effect of chromium and titanium carbides.
  • Effects of Titanium and Heat Treatments on Creep Properties of 15Cr-14Ni Heat Resisting Steels

    pp. 1948-1960

    Bookmark

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

    Log in / Sign Up
    To determine the optimum titanium content and heat treatments for 15Cr-14Ni heat resisting steels, an investigation has been carried out on their effects on the creep properties. The effects of precipitates on creep properties have been discussed.
    The creep rupture and creep strengths are found to have a maximum at Ti/C ratio of 2.0-4.0.
    The creep rupture and creep strengths decrease with increasing solution temperature at Ti/C ratio of zero, have a maximum at the solution temperature of 1150°C at Ti/C ratio of 0.1-1.0, and increasewith increasing solution temperature at Ti/C ratio of 1.0-8.0. The creep rupture strength increases with increasing (%C)×(%Ti)×(nI) 1/2×Dγ, where (%C) sol is dissolved carbon content, (%Ti) sol. is dissolved titanium content, nI is distribution density of undissolved carbide, and Dγ is grain diameter. This is interpreted by the combination of the following two factors; the solution strengthening of carbon and titanium and the dispersion strengthening of undissolved carbide and precipitated M23C6 and TiC.
  • Embrittlement of 304 Stainless Steel in Hydrogen under High-temperature and Pressure Environment

    pp. 1961-1970

    Bookmark

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

    Log in / Sign Up
    The change of mechanical properties of 304 stainless steel exposed to hydrogen at high temperature and high pressure was examined with reference to the change of the morphology and distribution of M23C6 carbide in the steel.
    Hydrogenated 304 stainless steel was very brittle when M23C6 carbides precipitated continuously at grain boundary in the form of developed dendritic particles. The fracture mode of hydrogenated 304 steel aged at 650°C for 70hr changed from a ductile to an intergranular type depending on the carbide morphology and its distribution. A ductile fracture mode, however, reappeared with dehydrogen treatment in vacuum. Hydrogen was observed to evolve at the grain or twin boundary of 304 steel. Therefore it is suggested that hydrogen is trapped at the interfaces of the grain or twin boundary carbides, and the nucleation and propagation of hydrogen embrittlement cracking may be caused by hydrogen trapped there.
  • Determination of the Amount of V4C3 Precipitates in a Low Carbon Vanadium Steel by Means of Slip Trace Method

    pp. 1971-1983

    Bookmark

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

    Log in / Sign Up
    Determination of the amount of V4C3 precipitates was carried out by means of “Slip Trace Method” using a 0.03%C-0.25%V steel subjected to a homogeneous dispersion heat treatment including solution treatment, cold working, and aging.
    Assuming that the shape of V4C3 particles was spherical, the calculated amount of V4C3 precipitates was 0.184%, which was about 41% larger than that obtained by an electrolytic isolation method (0.133%).
    The origins of the error introduced into the calculated amount of the precipitates were discussed. Larg errors were caused by inaccurate measurement of the shape of precipitates. The inclination ofth e specimen (thin foil) surface can also become the origin of large error. In addition, the volume fraction of precipitates tends to be overestimated by the existence of strain fields and/or dislocations around the precipitates.
    It was concluded that application of the “Slip Trace Method” to b. c. c. alloys was not so easy as to f. c. c. alloys since the determination of a unique slip plane from a pair of slip traces was difficultbecause of multiple slip system.
  • Effect of Heat Treatment and Cold Rolling of Steel Sheet on Phosphate Coating

    pp. 1984-1993

    Bookmark

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

    Log in / Sign Up
    This investigation has been carried out in order to show how heat treatments and cold rolling of steel sheets influence the phosphate coating and to make clear the relationship between the microstruc-ture of the steel and the phosphate nucleation.
    The activity of phosphate reaction is determined by the number of phophate nuclei initially formed on the steel surface when commercial phosphate solutions are sprayed.
    It is found that the activity of phosphate reaction is considerably affected by heat treatments andcold rolling of steel sheet; the phosphate nuclei increase with an increase of cold reduction and a raise of annealing temperature, decrease with an increase of the heating rate and a raise of the quenching temperature.
    The consideration of the above results from the microstructural point of view leads to the conclusion that the preferred orientation of steel (mainly (111) texture paralleled to the rolling surface) has the greatest effect on the phosphate nucleation, and the cementite in the steel has the next on it, while the grain size (grain boundary) of the steel has little effect.
    These conclusions are supported by experiment of the phosphate nucleation on single crystals of iron and large grains of steels.
  • A Method for Estimating Amount of Reaction Between Steel Sheet and Liquid Zinc Alloy in Continuous Galvanizing

    pp. 1994-2003

    Bookmark

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

    Log in / Sign Up
    1) Arithmetrical formulae have been derived on the amounts of dssolved iron into a galvanizing bath and iron in alloy layers in the continuous sheet galvanizing process influenced by working conduction, such as the aluminium content in the bath, the line-speed and the temperature of the sheet.
    First the quantities of dissolved iron ΔW1 (g/m2) and iron in the alloy layer ΔW2 (g/m2) are studied in relation to three separate variables; the aluminium content in the bath, y (%), the immersion time, t (sec), and the temperature of the sheet, θ(°C). Then equations of first degree or second degree are derived from these studies, and these equations are combined to arithmetrical formulae using the common conditions in these studies. For example, the formulae for the bath containing 0.12-0.14% Al is as follows:
    2) A study has been carried out to estimate the aluminium concentration in the coating on the basis of the quantity of iron in the alloy layer. The aluminium concentration in the alloy layer is lower than that estimated from the equilibrium diagram.
    x

    Readers Who Read This Article Also Read

    1. Dissolution of Iron in Molten Zinc in Continuous Sheet Galvanizing Tetsu-to-Hagané Vol.59(1973), No.1
  • Effect of Environments on Fatigue Strength of Steels

    pp. 2004-2010

    Bookmark

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

    Log in / Sign Up
    It is well known that the fatigue strength of steels is decreased by oxygen and/or humidity in the atmospheres. Only few reports have been published, however, on the effect of impurities such as SO2 gas on the fatigue strength of steels. In order to study the effect of SO2 gas on fatigue strengths of steels, rotating bending fatigue tests of a mild steel, a 60 kg/mm2 and an 80 kg/mm2 high strength steels and an 18-8 stainless steel have been corned out in various atmospheres. The employed atmospheres are air, humidified a'r, dry SO2 gas, mixed gas of dry SO2 and humidified air, mixed gas of dry H2S and humidified air, H2O, and H2SO4.
    On the fatigue strength of the mild steel the influence of dry SO2 gas is not recognized, but the influence of mixed gas of dry SO2 gas and humidified air is detected. The degree of the influence, however, is almost the same as that in humidified air. Therefore the influence of SO2 gas on fatigue strength of the mild steel seems to be little, but some influences of SO2 gas can be surmised from the characteristic aspect of fractured surfaces. On the 60 kg/mm2 and 80 kg/mm2 high strength steels and the 18-8 stainless steel the influence of SO2 gas is not observed. For all the steels tested in this experiment, the influence of H2SO4 is very conspicuous.
  • Report of the X-ray Thickness Gage Sub-committee

    pp. 2011-2017

    Bookmark

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

    Log in / Sign Up
  • 第85回講演大会討論会報告

    pp. 2018-2022

    Bookmark

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

    Log in / Sign Up
  • 抄録

    pp. 2023-2032

    Bookmark

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

    Log in / Sign Up

Article Access Ranking

22 Jan. (Last 30 Days)

  1. 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
  2. Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies Tetsu-to-Hagané Vol.105(2019), No.1
  3. Heat Transfer Characteristic of Slit Nozzle Impingement on High-temperature Plate Surface ISIJ International Advance Publication
  4. 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
  5. Preparation of High-Carbon Metallic Briquette for Blast Furnace Application ISIJ International Vol.59(2019), No.1
  6. Fusion Zone Microstructural Evolution of Al-10% Si Coated Hot Stamping Steel during Laser Welding ISIJ International Vol.59(2019), No.1
  7. 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
  8. Recent Progress on Advanced Blast Furnace Mathematical Models Based on Discrete Method ISIJ International Vol.54(2014), No.7
  9. Preface to the Special Topics Entitled “To Solve Problems of Hot Rolling Rolls” Tetsu-to-Hagané Vol.104(2018), No.12
  10. Effects of Sulfur and Titanium Interaction in Molten Pig Iron on Erosion of Carbon Brick ISIJ International Vol.59(2019), No.1

Search Phrase Ranking

22 Jan. (Last 30 Days)

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