Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 68 , Issue 10
Showing 1-24 articles out of 24 articles from the selected issue
  • Hideo OSAWA, Kiyoo ONO
    1982 Volume 68 Issue 10 Pages 1479-1488
    Published: August 01, 1982
    Released: January 18, 2010
    JOURNALS FREE ACCESS
    Download PDF (1919K)
  • Hiroshi OIKAWA
    1982 Volume 68 Issue 10 Pages 1489-1497
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (1111K)
  • Toyonobu YOSHIDA, Kazuo AKASHI
    1982 Volume 68 Issue 10 Pages 1498-1502
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (5676K)
  • Munekazu OHMI, Masaaki NAITO, Tateo USUI
    1982 Volume 68 Issue 10 Pages 1503-1512
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Effects of firing temperaturc (1100°1300°C), slag content (5, 10 wt%), basicity [(wt%CaO)/(wt%SiO2)=02], total porosity (0.050.45), and reduction temperature(800°1000°C)upon the reduction rate of hematite pellets are examined. Their pore-radius distributions, swelling, and microstructures in the course of reduction vary with the above-mentioned factors.
    Swelling and pore-radius distribution of unreduced pellets influence the reduction rate in the early stage; the pellets of basicity 0.52 indurated at 1 250°C and pure hematite pellets of total porosity 516% indurated at 1 300°C have many closed-pores and/or small pores below 0.2 μ and show poor reducibility. The other pellets have many large open-pores and their reducibilities become better as total porosity and swelling increase.
    In the later stage, the reduction rate varies according to the amount and diameter of wüstite particles encircled with dense iron (particle E) ; the reduction of basic pellets at 1 000°C is retarded remarkably in this stage, because the diameter of particle E is large (10 μ). As the diameter of particle E decreases, the reduction rate increases. Pellets having almost no particle E (e. g. the pellets of basicity 0.5) show good reducibility.
    The pellets of basicity 01 indurated at 1 150°C have the best reducibility at the final stage.
    Download PDF (7595K)
  • Ichiro SHIGAKI, Mineo SAWADA, Masahiro MAEKAWA, Kiichi NARITA
    1982 Volume 68 Issue 10 Pages 1513-1522
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    The mechanism of the degradation of agglomerates during the reduction was studied for experi-mentally made pellets and the change in mineral phases by some oxides, affecting the degradability, was examined quantitatively by the synthetic system of chemical reagents.
    The results obtained are summarized as follows:
    (1) The microscopic observation suggests that cracking occurs at skeletal hematite and calcium ferrite phases. By the analysis of line-broadening measurements of X-ray diffraction, no strain is detected in both bulky and skeletal hematites regardless of the solution of alumina. Micropores are generated in magnetite reduced from hematite to bring stress for the reduction at low temperatures and stress concentrations are considered to occur around inclusions of small radius of curvature to cause cracking of skeletal hematite grains.
    (2) Quarternary calcium ferrite is reduced to metallic iron in the blast furnace through dicalcium ferrite or wustite. Nonferrous oxides form gehlenite and β-dicalcium silicate.
    (3) The amount of skeletal hematite depends mainly on the degree of supersaturation of iron ions in slag and the dissociation temperature of hematite. This is influenced by nonferrous oxides such as MgO, Al2O3, and TiO2.
    Download PDF (11478K)
  • Hiroaki NISHIO, Tatsuro ARIYAMA, Kazumasa WAKIMOTO, Atsushi YAMAGUCHI
    1982 Volume 68 Issue 10 Pages 1523-1531
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Although many efforts have been made to control the burden distribution, there was not yet adequate information to obtain the best control. Therefore, Nippon Kokan K. K. built a full scale 36° segment model equipped with two bells, movable armors, a burden discharge facility and a cold blast supply facility. A number of experiments were made to obtain the burden and gas distribution.
    The results of these experiments have been utilized to improve the burden and gas distribution in Fukuyama No. 4 BF; the change from two-batch charging to one-batch charging leading to a more uniform burden distribution resulted in the decrease in fuel rate by 10 kg/THM.
    Download PDF (1177K)
  • Ryo INOUE, Hideaki SUITO
    1982 Volume 68 Issue 10 Pages 1532-1540
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Experiments have been made to study the vanadium distribution between liquid iron and the CaO-MgO-FeOx-SiO2 slag equilibrated in a magnesia crucible in the temperature range from 1 550° to 1 650°C. The vanadium distribution ratios were about an order of magnitude higher and their dependence of slag composition and temperature was found to be smaller compared with the phosphorus distribution ratios. A linear relationship was observed between logarithm of (V) / ([V] [O]n) (n=2 or 2.5) and CaO/SiO2 ratio. The V4+/(V4++V5+) ratio decreased with increasing CaO/SiO2 ratio, while V3+, V4+ ions were observed in the slag compositions of CaO/SiO2<1. Phosphorus, silicon, and vanadium distribution ratios between slag and carbon saturated iron melt was obtained at 1 350°C by use of the distribution ratios between slag and liquid iron at a high temperature and interaction parameters.
    Download PDF (1582K)
  • Hideaki SUITO, Ryo INOUE
    1982 Volume 68 Issue 10 Pages 1541-1550
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Experiments have been made to study the phosphorus distribution between liquid iron and MgO-saturated CaO-MgO-FeOx-SiO2 slags containing 1 to 4% CaF2 in the temperature range from 1550° to 1650°C. The effect of CaF2 on the equilibrium quotient kp(=(%P2O5)/{[P]2(%FeO)5}) was found to be nearly equal to that of CaO on a weight percentage base. The equilibrium quotient kp is expressed as log kp-8.22log[(%CaO)+(%CaF2)+0.3(%MgO)-0.05(%FeO)]+21460/T-27.02
    or log kp-0.156[(%CaO)+(%CaF2)+0.3(%MgO)]+20730/T-19.48
    The effect of CaF2 on the activity coefficient of P2O5 was also studied by TURKDOGAN and PEARSON'S treatment. The following expression for the activity coefficient of P2O5 was given for CaF2-containing slags.
    logγP2O5=-1.01(23NCaO+21NCaF2+17NMgO+8NFeO)-26300/T+11.24
    It was found from the plot of the activity coefficient of FeO versus mole fraction of SiO2 that activities of FeO increased with addition of CaF2.
    Download PDF (1495K)
  • [in Japanese], [in Japanese]
    1982 Volume 68 Issue 10 Pages 1550-1550,1647
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (552K)
  • Fujio ISHII, Shiro BAN-YA, Tasuku FUWA
    1982 Volume 68 Issue 10 Pages 1551-1559
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Solubilities of nitrogen in liquid Fe-C, Fe-Al, Fe-Si, Fe-P, Fe-Mn and Fe-Ni alloys are measured in the temperature range of 1540° to 1680°C by sampling method.
    The solubility of nitrogen in liquid iron decreases by addition of C, Al, Si, P and Ni, while it increases by addition of Mn. The effects of alloying elements on the activity of nitrogen in liquid iron at 1580°C are summarized as follows:
    logfCN=0.13 [%C] 3%C
    logfAlN=0.010 [%Al] 3.8%Al, PN2=0.15-1.0atm logfSiN=0.060 [%Si] 3%Si logfPN=0.046 [%P] 5%P
    logfMnN=-0.020 [%Mn] 9%Mn logfNiN=0.011 [%Ni] 10%Ni.
    Download PDF (1271K)
  • Fujio ISHII, Tasuku FUWA
    1982 Volume 68 Issue 10 Pages 1560-1568
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Solubilities of nitrogen in liquid Fe-Ti, Fe-V, Fe-Cr, Fe-Mo, and Fe-W alloys are determined in the temperature range of 1580°C to 1 680°C by sampling method.
    The results obtained show that addition of Ti, V, Cr, Mo, and W increases the solubility of nitrogen in liquid iron. The effects of alloying elements on the activity of nitrogen in liquid iron at 1 580° are expressed as follows:
    logf TiN=-0.9 [%Ti] <0.15%Ti, PN2=0.040.17atm logf VN=-0.10 [%V] <6.5%V
    logf CrN=-0.047 [%Cr] <9%Cr logf MoN=-0, 009 [%Mo] <9%Mo logf WN=-0.003 [%W] <9%W.
    Download PDF (1233K)
  • Yoichi ITO, Noboru YONEZAWA, Kaichi MATSUBARA
    1982 Volume 68 Issue 10 Pages 1569-1577
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Steels containing 0.25% carbon, 0.03% sulfur and 0.3 to 1.2% manganese were melted and quenched at various temperatures between the final stage of solidification and 400°C. The number, volume fraction and distribution of sulfides were investigated in connection with the grain boundary and dendritic structure.
    Sulfides were grouped into two categories; the first was crystallized by a eutectic reaction and the second was precipitated from solid steel. The increase in manganese content and cooling rate was favorable to the formation of eutectic sulfides. These were mainly distributed at grain boundaries and interdendritic regions. On the other hand, precipitated sulfides increased in number as the manganese content and cooling rate decreased. These sulfides were classified into the colony type and non-colony type. The former was observed mostly at grain boundaries, and the latter tended to be precipitated within grains and dendrite arms.
    Download PDF (12241K)
  • Yoshiaki IGUGHI, Michio INOUYE
    1982 Volume 68 Issue 10 Pages 1578-1585
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    The effects of foreign oxides on the oxidation behavior of reduced iron are investigated and the following results are obtained. The oxidation starting temperature of iron reduced from pure hematite and hematite containing Al2O3 or CaO at 800°C are about 430°, 300° and 460°C, respectively. It is found that oxidation of reduced iron apparently stop before being completely oxidized to ferric oxide, when iron reduced from hematite containing a sufficient amount of CaO is oxidized at the temperature higher than 600°C. The higher the oxidation temperature and the lower the water vapor pressure, the lower the oxidation degree. Further, the oxidation degree depends on the content of CaO and shows the minimum at 1.25 mol% CaO. On the other hand, iron reduced from hematite containing Al2O3 is oxidized towards the complete oxidation without the apparent stop of oxidation The porosity of iron reduced from hematite containing CaO and Al2O3 is practically the same and higher than the critical porosity except the case of the extremely low content of CaO. The contraction during oxidation of reduced pellets containing CaO and decrease of pore radius by the oxide built upon the wall of pore are considered to be the cause of the apparent stop of oxidation.
    Download PDF (3445K)
  • Tetsuya FUJII, Yukio OGUCHI, Norio SUMIDA, Toshihiko EMI
    1982 Volume 68 Issue 10 Pages 1586-1594
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Pulsating Mixing (PM) process has been devised for refining molten steel in ladle. The objectives of the new process are summarized as follows:
    (1) Retaining the same ability in deoxidation and alloy trimming as those of RH treatment.
    (2) Minimizing the contamination of steel, such as rephosphorization and reoxidation, arizing from top slag during the treatment.
    (3) Significantly decreasing operation cost and investment in comparison with those for RH- or DH-process.
    Water model experiments have been carried out with a 1/3 scale model apparatus for investigating the feasibility of the process, showing that the process satisfies the above requirements. A mathematical model has been developed based on the water model experiments for the basic designing of a com-mercial scale PM facility. The dimensions and operational conditions of the facility have been discussed to achieve the same stirring intensity, hence the same ability in deoxidation treatment, as that obtainable in RH treatment.
    Download PDF (1313K)
  • Tetsuya FUJII, Yukio OGUCHI, Norio SUMIDA, Toshihiko EMI, Kunihiko ISH ...
    1982 Volume 68 Issue 10 Pages 1595-1603
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Commercial scale experiments have been carried out to develop a new ladle refining process termed PM (Pulsating Mixing Process) invented on the basis of water model experiments and theoretical calculations. The results obtained for a 100 t PM facility are as follows:
    (1) The rate of input of stirring energy is calculated to be 5 to 10W/t steel, equivalent to that obtained for an RH degasser.
    (2) The rate of deoxidation and oxygen concentration after the treatment are shown for aluminum and aluminum-silicon killed steels to be close to those for RH treatment.
    (3) Yield of additions, such as Al and C, for trimming during the treatment is found to be larger than 85%, approximately the same as that for RH treatment.
    (4) The rate of the decrease in temperature of the melt throughout the treatment is on the average 1.7°C/min, about 30% smaller than that for RH treatment.
    (5) As far as deoxidation and trimming of alloys are concerned, the PM process is much superior to conventional argon bubbling, and comparable with RH- or DH-degassing.
    Download PDF (1461K)
  • Yoshiei KATO, Kyoji NAKANISHI, Tsutomu NOZAKI, Kenichiro SUZUKI, Toshi ...
    1982 Volume 68 Issue 10 Pages 1604-1612
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Water model experiment has been carried out to investigate motion of bath in bottom blown converter with tuyeres set in two rows.
    Visual observation has indicated the occurrence of two types of wave motions (A- and B-type). A type of wave motion is similar to that generated in a U-shaped tube. B type resembles that two separated bubble regions interfere laterally and repeat collision and repulsion alternately.
    The generation of wave motions is varied by gas flow rate, bath depth and tuyere configuration. On keeping gas flow rate at which either of the wave motion is generated, the criterion for the generation of wave motion has been characterized by H/D and L2/L1, where H is the bath depth, D is the bath depth, D is the diameter of the bottom, L2 is the spacing of the two rows of tuyeres, and L1 is the length of the row of tuyeres.
    Period of the wave motion is calculated by means of simple models. The calculated results agree well with the observed ones for a variety of experimental conditions.
    A type of wave motion carries larger energy of oscillation than that of B type at the same rate of energy input into the bath, indicating that B type of wave motion occurs in preference to A type version.
    Download PDF (3699K)
  • Klaus WÜNNENBERG, Hatto JACOBI
    1982 Volume 68 Issue 10 Pages 1613-1620
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    The extension of columnar or equiaxed zone in the as-cast structure of continuously cast slabs is primarily affected by the superheat temperature in the tundish, high temperatures promoting the form-ation of columnar grains and low temperatures that of equiaxed grains. At an intermediate temperature a sharp transition in the extent of each structure occurs. The formation of equiaxed crystals is enhanced by high freezing rates of the solid shell and by turbulent fluid flow. Under favourable conditions free crystals already exist in the mould. In bow type machines sedimentation of such suspended crystals is a geometrical phenomenon and depends on parameters such as machine radius, casting speed and heat extraction.
    The experiment shows that in slabs of bow type machines the cast structure is asymmetric, the equiaxed zone extending further to the outer radius. At intermadiate superheat temperatures sedimenta-tion zone is entirely located within the lower strand section terminating distinctly below the centre line.Consequently the formation of free crystals may end before completion of strand solidification. Con-centration profiles of partly equiaxed solidified slabs are used to verify the sedimentation mechanism.Carbon is taken as an example to illustrate the decrease of concentration in equiaxed zone.
    Download PDF (6721K)
  • Yasunori TORISAKA, Masayuki YOKAI, Shoji SHIMAMURA, Matsuo MIYAGAWA
    1982 Volume 68 Issue 10 Pages 1621-1627
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Studies on quantitative analysis of image structures were performed; the analysis was indispensable to computer-aided-material-designing and fracture analysis.
    After examining various quantitative methods, we used the improved face method which transformedimage structures to "the human face" and obtained satisfactory results.
    The procedure is as follows:
    (1) Define "the face" in case of no image structures.
    (2) Extract information from image structures.
    (3) Obtain "the face" corresponding to image structures by deforming "the face" of (1) on the basis of the information of (2).
    Download PDF (8676K)
  • Masami SHINDO, Tatsuo KONDO
    1982 Volume 68 Issue 10 Pages 1628-1637
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Roles of Mn and Si in Hastelloy alloy X were examined in terms of the high temperature oxidation behavior of several experimental heats at 1000°C in flowing helium containing very small amounts of impurities. Both elements were found to have significant influence both on the steady state oxidation rates, evaluated as Cr consumption rate, and on the oxide film spallation resistance. In such a special environment, characterized by very low oxygen potential, the following effects were observed:
    1) Within the range (max. 1.32 wt%) tested addition of Mn improved the oxidation resistance nearly propotionally to the increase of Mn content. The effect was interpreted in formation of the outer MnCr2O4 spinel oxide layer outside the inner Cr2O3 oxide layer.
    2) Addition of Si caused the similar effect on the steady state oxidation rate to the maximum (1.02 wt%) amount tested. The degree of adherence of the protective oxide film, however, was maximized at around 0.3 wt%, above and below which spallation of oxide film tended to occur with either increasing or decreasing Si content. These two could be explained in formation and morphology of the Si oxide phase in the oxide and metal interface.
    Download PDF (9115K)
  • Toshio OKUNO
    1982 Volume 68 Issue 10 Pages 1638-1647
    Published: August 01, 1982
    Released: January 19, 2010
    JOURNALS FREE ACCESS
    The effect of bainite structure on the toughness of the 0.2C-3Cr-W-Mo-V-Co steel was investigated.
    The results obtained are as follows:
    (1) The granular upper bainite structure, which was obtained by quenching at a rate of the half temperature time of 60 min provided the following superior as well as inferior aspects compared to the martensite structure tempered at 400°C. (i) Inferior aspects are lower plane strain fracture toughness and higher transition temperature in charpy impact testing. (ii) Superior aspects are lower fatigue clack propagation rate, higher upper shelf energy in charpy impact testing, and higher uniform elongation in tensile testing.
    (2) Microstructural factors dominant to the above behavior on the toughness of bainite could be summarized as follows. (i) Larger width of granular bainite grain and larger size of microstructural unit relevant to the effective grain size increase the cleavage fracture sensitivity. (ii) Excessively stable retained austenite located both along grain boundaries and in grains improves the toughness. (iii) Suppressed precipitation of M3C carbide improves the toughness.
    (3) When this bainite structure was tempered at higher temperatures of 550 to 650°C, this structure showed the lower toughness than the martensite structure because of reasons of higher distribution density of fine MC and M2C carbide precipitates, etc.
    Download PDF (11576K)
  • Masao OGASAWARA
    1982 Volume 68 Issue 10 Pages 1648-1655
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Drop Weight Tear Test is widely used as a testing method for evaluating the brittle crack arrestability of linepipe steels. Since this approach is originally based on the good correlation obtained between the results of full scale brittle propagation test and the shear appearance of DWTT, it is not clear if the same analogy could be applied for the recent large diameter and thick pipelines of newly developed steels.
    In the present investigation, a trial is proposed to analyse the DWTT by the fracture mechanical method and to obtain the Kca (fracture mechanical parameter for the brittle arrest) from the shear appearance of DWTT. It is possible to explain the design criterion of the transition theory (DWTT) by the design philosophy of the fracture mechanics.
    Download PDF (4098K)
  • Saburo YASHIMA
    1982 Volume 68 Issue 10 Pages 1656-1661
    Published: August 01, 1982
    Released: January 19, 2010
    JOURNALS FREE ACCESS
    Download PDF (1074K)
  • Jean-Jacques LAVIGNE
    1982 Volume 68 Issue 10 Pages 1664-1667
    Published: August 01, 1982
    Released: January 18, 2010
    JOURNALS FREE ACCESS
    Download PDF (713K)
  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1982 Volume 68 Issue 10 Pages 1671-1674
    Published: August 01, 1982
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (719K)
feedback
Top