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. 64 (1978), No. 6

  • Clustering Phenomena during Iron Oxide Reduction in Shaft Furnace

    pp. 681-690

    Bookmark

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

    Log in / Sign Up
    In the direct reduction shaft furnace it is favorable to raise reducing gas temperature blown from tuyeres to improve not only the productivity but also characteristics of the sponge iron for reoxidation. However, if the operating temperature is too high, the material become sticky and form so called clusters. Thus authors investigated clustering behavior of iron oxide during its reduction by a laboratory test.
    Pellet with iron content of 64-68% and lime (CaO) content of 0.09-1.11% were produced by an indurating furnace of bench scale. Five hundred grams of fired pellets were charged into the reduction tube with inside diameter of 75 mm and were reduced with reducing gas (H2: 55%, CO: 36%, CO2: 5%, CH4: 4%) under load at a temperature range of 700-960°C. The expansion or shrinkage ratio of the sample bed was continuously recorded using a strain gage. The strength of clusters formed during reduction was measured in a rotating steel drum with diameter of 120mm and length of 700mm. It was found that the shrinkage ratio of the pellet bed was clearly related to the cluster, and the higher the shrinkage ratio, the stronger the cluster.
    The formation of the cluster during reduction depended on three factors., i. e. the temperature, load on the burden bed and properties of materials. The relationship of these factors as well as clustering mechanism of reduced materials were discussed based on the experiments.
  • Influence of Operational Factors on Thermal and Chemical Conditions at Lower Part of Blast Furnace

    pp. 691-700

    Bookmark

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

    Log in / Sign Up
    The operational data of blast furnace performance for longer periods are analyzed by the following parameters as adiabatic flame temperature, height for heat exchange and height of melting level, as well as indices of the thermal state RSi and the reduction behavior of ferrous oxide RS and RMn at the lower part of blast furnace. The results are as follows.
    (1) The temperature of melts changes with the adiabatic flame temperature and height for heat exchange, and is related to the heat balance.
    (2) RSi gives the same expression as that for thermal state representing the extent of coke reserve zone.
    (3) With lower quality coke, RSi, RS and RMn decrease markedly even in a regular operation; this indicates increasing FeO content in slag at the hearth.
    (4) The increase of sulfur content in injected oil decreases the S distribution ratio between slag and metal. On the other hand, the increase of sulfur content in coke has no influence on it. These differences are caused by the transfer mechanism to gas phase.
  • Kinetics of Nitrogen Desorption of Liquid Iron, Liquid Fe-Mn and Fe-Cu Alloys under Reduced Pressures

    pp. 701-710

    Bookmark

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

    Log in / Sign Up
    The rates of nitrogen desorption of inductively stirred liquid iron have been measured under reduced pressure at 1600°C and the effects of manganese and copper on the rates are discussed.
    The rates of nitrogen desorption are apparently represented by the equation of 2nd order reaction in terms of nitrogen content in liquid iron as shown by the previous investigators under argon atmosphere. The values of the rate constant of nitrogen desorption, kN, decrease with increasing oxygen-content in liquid iron and are nearly agreed with those obtained by other authors at higher concentration range than 0.02%. At low concentrations of oxygen in melts, however, the values of kN obtained in the present work are higher than any of those by the others, though there are some discrepancies among them. These results are explained by the application of the mixed-control model including the mass transfer in both phases and the chemical reaction at the interface. Although the rate of nitrogen desorption has been regarded as the chemical reaction control, the mass transfer in liquid iron may play an important role on the nitrogen desorption at the lower oxygen range. It is also found that the vapourization of manganese or copper in liquid iron decreases the rate of nitrogen desorption, probably because of the local decrease of interfacial temperature due to the latent heat of vapourization and also because of the decrease of the effective reaction site for the nitrogen desorption.
  • Measurement of Electrical Resistivity of Molten Iron, Cobalt, and Nickel by Improved Four-Probe Method

    pp. 711-719

    Bookmark

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

    Log in / Sign Up
    For the precise measurement of the electrical resistivity of molten metals at high temperature, the fourprobe method has been improved by use of a newly designed cell in which the four electrodes made of the same material as the specimen were installed.
    The results of the preliminary experiment on molten tin and copper were in excellent agreement with those of the previous studies by other investigators, and it was proved that “the improved four-probe method” was quite suitable for the measurement of the electrical resistivity of molten metals at high temperature.
    The electrical resistivity of molten iron, cobalt and nickel, obtained in the temperature range from melting point to about 1 660°C (iron) and 1 620°C (cobalt and nickel), showed a linear dependency on temperature as represented by the following equations.
    Fe: ρ (μΩ·cm) =0.0154t (°C) +112.3
    Co: ρ (μΩ·cm) =0.0192t (°C) +91.8
    Ni: ρ (μΩ·cm) =0.0116t (°C) +70.2
    Probable error in the measurement was estimated to be about ±0.2%. The ratio of the resistivity of the liquid metal (ρl) to the solid metal (ρs) at melting point was evaluated to be 1.06, 1.14 and 1.40 for Fe, Co and Ni respectively.
  • Silicon-Oxygen Equilibrium in δ-Iron at the Solid-Liquid Equilibrium Temperature

    pp. 720-729

    Bookmark

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

    Log in / Sign Up
    Experiments on the solid-liquid equilibrium relationship in Fe-Si-O alloys were carried out using the zone melting technique.
    The deoxidation constant with silicon in liquid iron was log KSi (l) =-5.18 ([%Si (l)] <0.64) at the solid-liquid equilibrium temperature, which is in good agreement with the values given in the literature.
    The silicon-oxygen equilibrium relationship in δ-iron at the solid-liquid equilibrium temperature is represented by the following equations:
    log aSi (s) ·aO (s) 2=-7.19 ([%Si (s)] ≤0.5)
    log fSiSi (s) =0.086 [%Si (s)]
    log fOSi (s) =-15.9 [%O (s)]
    log fSiO (s) =-9.05 [%Si (s)] +30 [%Si (s)] 2 ([%Si (s)] ≤0.1)
    log fOO (s) ≈0
  • Theoretical Analysis and Model Study of the Formation of Channel-Type Segregation

    pp. 730-739

    Bookmark

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

    Log in / Sign Up
    A mathematical model of a channel-type segregation is developed on the basis of the stability theory. By focusing on the difference of the cooling conditions, the instability phenomena inducing the segregation are theoretically analyzed by use of the model.
    The analytical results are confirmed by the model experiments. In these experiments, the aqueous solutions of NH4Cl are freezed by cooling from the top or the bottom of a mold having the adiabatic side walls or by cooling through the side walls.
    Thermal insulation of the side walls are essential for preventing the channel-type segregation. When a mold is cooled through its side walls, controlled preparation of the alloy elements is required to prevent the formation of segregation.
    x

    Readers Who Read This Article Also Read

    1. Heat Transfer Phenomena in Immersion Cooling of Heated Steel Plate and Influence of Water Stirring on Heat Transfer Tetsu-to-Hagané Vol.64(1978), No.1
    2. 第97回講演大会討論会講演概要 Tetsu-to-Hagané Vol.65(1979), No.2
    3. 第95回講演大会討論会講演概要 Tetsu-to-Hagané Vol.64(1978), No.2
  • Separations Occurring at the Fracture Surfaces of Controlled Rolled Hot-Strips

    pp. 740-748

    Bookmark

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

    Log in / Sign Up
    Using a laboratory simulation method for producing coiled-strips and plates, a study has been made on the separations occurring at the fracture surfaces of tensile and Charpy specimens of high strength low alloy steel containing 0.04%Nb and 0.09%V. Main results are summarized as follows:
    (1) Even by the same rolling process with a finishing temperature of 780°C, the separations of coiledstrips on Charpy specimens are more remarkable than those of plates. Also, separations occur at the fracture surfaces of tensile specimens for coiled-strips, although they can hardly be observed in case of aircooled plates.
    (2) The plates which are air-cooled to room temperature and then tempered at the temperature similar to that of coiling, show the separations on tensile specimens.
    (3) The separations in coiled-strips are accelerated by temper-embrittling elements such as phosphorus or manganese, and are reduced by molybdenum which is known to be the suppressing element for temperbrittleness.
    (4) For coiled-strips, the separations are found to closely correlate with the layer of segregation of phosphorus, and the cracks are mainly through the grain boundary of the ferrite.
    (5) From these results, it is concluded that the separations of coiled-strips are caused by temper-brittleness during the slow cooling after coiling i. e., phosphorus in a segregated layer moves to ferrite grain and deteriorates the toughness of the boundaries.
    x

    Readers Who Read This Article Also Read

    1. 日本鉄鋼協会第96回講演大会講演概要 Tetsu-to-Hagané Vol.64(1978), No.11
    2. 随想 Tetsu-to-Hagané Vol.64(1978), No.12
    3. Low Temperature Ductility of 11%Ni Steels Having Various Microstructures Obtained by Heating in α+γ Duplex Phase Region Tetsu-to-Hagané Vol.64(1978), No.6
  • Low Temperature Ductility of 11%Ni Steels Having Various Microstructures Obtained by Heating in α+γ Duplex Phase Region

    pp. 749-758

    Bookmark

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

    Log in / Sign Up
    Tensile testing has been carried out in the temperature range from -196°C to room temperature. Highly tempered martensite (plus fine dispersed retained austenite) microstructure, observed in specimens heated in the vicinity of As temperature, shows the best low temperature ductility. Heating in the vicinity of Af temperature, lath-type fresh martensite with some small recrystallized equiaxed grains is observed and shows relatively a good ductility. On the other hand, a highly recovered ferrite with fresh martensite structure, obtained by heating in the intermediate range of α-γ duplex phase region, yields a poor ductility. All these structures, especially the former two ones, exhibit larger uniform elongation at lower temperature down to -196°C. No trace of martensitic transformation of retained austenite is detected by cooling down to -269°C, but a little plastic deformation at -78°C makes most of retained austenite transform to martensite. Such a transformation induced by deformation is also observed at room temperature. Considering the results of some other Fe-Ni alloys, the interrelationship between low temperature ductility and microstructures of 11%Ni steels is discussed.
    x

    Readers Who Read This Article Also Read

    1. 日本鉄鋼協会第96回講演大会講演概要 Tetsu-to-Hagané Vol.64(1978), No.11
    2. 随想 Tetsu-to-Hagané Vol.64(1978), No.12
    3. Separations Occurring at the Fracture Surfaces of Controlled Rolled Hot-Strips Tetsu-to-Hagané Vol.64(1978), No.6
  • The Strength and Ductility of a 0.42%C-Ni-Cr-Mo Steel Having Mixed Structure of Martensite and Bainite

    pp. 759-768

    Bookmark

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

    Log in / Sign Up
    A study has been made of the strength and ductility of a 0.42% C-Ni-Cr-Mo steel having mixed structure of martensite and bainite.
    It was found that lower bainite, which precipitated acicularly so as to partition prior austenite grains, had a desirable effect on the 0.2% proof stress regardless of tempering conditions, but had not necessarily on the elongation. Upper bainite, which precipitated massively so as to fill prior austenite grains, was found to have detrimental effects both on the 0.2% proof stress and elongation irrespective of tempering conditions.
    The beneficial effect of lower bainite on the 0.2% proof stress is attributable to the fact that the 0.2% proof stress deviates better from the general law of mixture, it resulting from the improvement of the strength of martensite owing to the refinement of its substructure, besides an increase in the strength of the bainite being due to higher plastic restraining of the bainite by martensite. The detrimental effect of upper bainite on it is attributable to the fact that it deviates worse from the law of mixture being due to ununiform strain of two-phase.
  • Effect of Hydrogen on Crack Propagation Behavior and Microstructures around Cracks in Austenitic Stainless Steels

    pp. 769-778

    Bookmark

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

    Log in / Sign Up
    The effect of hydrogen on the crack propagation behavior and the microstructures around cracks in SUS 304H type and SUS 310 type austenitic stainless steels was examined by means of the tensile tests and microscopic observations. The results obtained are summarized as follows:
    (1) For austenitic stainless steels, the yield strength and 2% flow stress are hardly dependent on the hydrogen content, whereas the fracture strain and the total energy on plastic deformation decrease remarkably as the hydrogen content increases.
    (2) According to the notch tensile tests, the force for crack initiation does not change with the hydrogen content very much but the elongation by crack opening and the amount of work required for the fracture decrease remarkably with increasing the hydrogen content.
    (3) An increase of absorbed hydrogen suppresses the strain induced transformation of α′ martensite, while it promotes the formation of ε martensite due to a lowering of the stacking fault energy by hydrogen.
    (4) It is concluded that the hydrogen embrittlement of austenitic stainless steels is mainly due to the formation of ε martensite in the vicinity of cracks by the absorption of hydrogen and the easy propagation of cracks along the boundary between austenite and ε martensite.
  • Effect of Tensile Prestrain on Low-Temperature Ductility of Fe-Cu Alloy

    pp. 779-786

    Bookmark

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

    Log in / Sign Up
    The effect of prestrain on the low-temperature ductility of Fe-1.83%Cu alloywas investigated as a function of prestrain temperature, prestrain quantity, and tensile testing temperature.
    Ductility of solution-treated Fe-1.83%Cu alloy at 77K decreased about 20% with increasing prestrain at room temperature, whereas, ductility of aged Fe-1.83%Cu alloy (25h at 700°C) increased about 10% at 120 and 77K, after prestrain of 2.4% at room temperature. However, the ductility did not increase, after any prestrain at 153K.
    Dislocation structure produced by prestrain of 2.4% at room temperature was observed, after 5% deformation at 77K for aged Fe-1.83%Cu alloy (96h at 700°C), but not for solution-treated Fe-1.83%Cu alloy.
  • The Embrittlement of Blackheart Malleable Iron

    pp. 787-796

    Bookmark

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

    Log in / Sign Up
    With the view of investigating the behavior of embrittlement of blackheart malleable iron, Charpy impact tests were carried out for series of specimens. The influences of phosphorus and/or nitrogen content, quenching temperature, holding time, and cooling rate were studied on the brittleness of these irons. Micro hardness test was also carried out on the ferrite grain interiors and its boundaries of irons subjected to a variety of treatments.
    Various kinds of surface analyzers such as IMA, ESCA, and AES are utilized for the analysis of the grain boundary fracture surfaces of the embrittled blackheart malleable iron.
    The results obtained are as follows.
    (1) Phosphorus has a close relationship to the embrittlement of blackheart malleable iron, while nitrogen appears not to give rise to brittle fracture.
    (2) Holding at 450°C results in the embrittlement of the iron.
    (3) The reversibility between brittle and ductile fracture is confirmed on the impact values.
    (4) Quenching from 650°C before 450°C embrittling treatment retards the appearance of brittle fracture in the iron having higher content of phosphorus.
    (5) Micro hardness test shows that an embrittled iron has a little increment of hardness at grain boundary, compared with that of grain interior of the same iron.
    (6) The remarkable segregation of phosphorus in the grain boundary of the embrittled iron is recognized by means of IMA, ESCA, and AES analyses.
  • Determination of Al, Ce, La, Nb and Zr in Steel by Using Optical Emission Spectrometry with an Inductively Coupled Plasma

    pp. 797-803

    Bookmark

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

    Log in / Sign Up
    Inductively coupled high frequency plasma (ICP) -optical emission spectrometry was used for the determination of some elements in steels. The determined elements were Ce, La, Nb, Zr and Al, and the former four ones cannot be determined by the atomic absorption method.
    The plasma was generated by the frequency of 27.120 MHz and the output power of 1600 watt. An 1.7-meter Ebert mounting spectrometer was used. Steel samples were completely dissolved by suitable acids, and diluted to the 0.5 wt% in solution level. The acids and the iron present in the sample solution affected slightly the emission intensity of each measuring element, but these interference effects were prevented by adding to the reference solution of the same amounts of acids and iron as in the sample solution.
    The determined values by this method closely agreed with the values by chemical analysis. The measuring time of this method for one sample solution was about 40 seconds. As the standard deviation in the micro amount region, 0.00017% for 0.002% Al sol, 0.00006% for 0.005% La, 0.00035% for 0.006% Ce, 0.00012% for 0.011% Nb and 0.00021% for 0.004% Zr were obtained.
  • Recent Technology of Continuous Casting and Instrumentation

    pp. 804-814

    Bookmark

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

    Log in / Sign Up
  • Recent Trends of High Steel Tool Steel

    pp. 815-822

    Bookmark

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

    Log in / Sign Up
  • 抄録

    pp. 823-827

    Bookmark

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

    Log in / Sign Up

Article Access Ranking

20 Jul. (Last 30 Days)

  1. Production and Technology of Iron and Steel in Japan during 2018 ISIJ International Vol.59(2019), No.6
  2. Perspective toward Long-term Global Goal for Carbon Dioxide Mitigation in Steel Industry Tetsu-to-Hagané Vol.105(2019), No.6
  3. Preface to the Special Issue “Fundamentals and Application Technologies for High-performance Hot-dip Galvanized Coatings” Tetsu-to-Hagané Vol.105(2019), No.7
  4. Influence of Annealing Temperature and Dew Point on Kinetics of Mn External Oxidation Tetsu-to-Hagané Vol.105(2019), No.7
  5. Microstructure and Phase of Carbon Brick and Protective Layer of a 2800 m3 Industrial Blast Furnace Hearth ISIJ International Advance Publication
  6. Insights into Accumulation Behavior of Harmful Elements in Cohesive Zone with Reference to Its Influence on Coke ISIJ International Advance Publication
  7. Recycling of Blast Furnace Sludge to the Blast Furnace via Cold-Bonded Briquettes: Evaluation of Feasibility and Influence on Operation ISIJ International Advance Publication
  8. Understanding the Structure and Structural Effects on the Properties of Blast Furnace Slag (BFS) ISIJ International Vol.59(2019), No.7
  9. Properties-to-microstructure-to-processing Inverse Analysis for Steels via Machine Learning ISIJ International Advance Publication
  10. Quantitative Analyses of Chemical Structural Change and Gas Generation Profile of Coal upon Heating toward Gaining New Insights for Coal Pyrolysis Chemistry ISIJ International Advance Publication

Search Phrase Ranking

20 Jul. (Last 30 Days)

  1. blast furnace
  2. blast furnace productivity
  3. 龍角散
  4. chinese academy of science
  5. blast furnace permeability
  6. continuous casting
  7. corrosion
  8. ladle furnace
  9. balling index
  10. cao-sio2-feo