Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 67, Issue 7
Displaying 1-23 of 23 articles from this issue
  • Takeshi HAYASHI
    1981 Volume 67 Issue 7 Pages 841-851
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Tadashi MAKI, Imao TAMURA
    1981 Volume 67 Issue 7 Pages 852-866
    Published: May 01, 1981
    Released on J-STAGE: January 18, 2010
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  • Takashi OTSUKI
    1981 Volume 67 Issue 7 Pages 867-879
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Shinsaku ONODERA
    1981 Volume 67 Issue 7 Pages 880-890
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Toshio SHIBATA
    1981 Volume 67 Issue 7 Pages 891-899
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Yutaka YOSHITANI
    1981 Volume 67 Issue 7 Pages 900-907
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Namio URABE
    1981 Volume 67 Issue 7 Pages 908-916
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Mayumi YOSIIINAGA, Koichi FUJI, Tatsuhiko SHIGEMATSU, Tetsuro NAKATA
    1981 Volume 67 Issue 7 Pages 917-924
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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    In order to develop the heat recovery process of the retained heat in molten blast furnace slag, several methods to granulate the molten slag and solidification of the molten slag granules were investigated.
    The developed method of dry granulation by collision of molten slag with a plate has several advantages as (1) low power consumption for granulation, (2) low heat loss during granulation, and (3) relatively short range of dispersion of the slag granules.
    A slag granule of 5 mm in diameter kept in the air flow is cooled at a rate of about 100 °C/sec in high temperature range and solidifies at a temperature of about 850°C. This means that it takes about 5 seconds to solidify a molten slag granule at a temperature of 1350°C. To accelerate the cooling rate and avoid mutual adhesion of slag granules, it is found to be effective to cool and solidify the slag granules by mixing with powder used as a cooling medium.
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  • Yasutaka IGUCHI, Yasuyuki TOZAKI, Mitsuo KAKIZAKI, Tasuku FUWA, Shiro ...
    1981 Volume 67 Issue 7 Pages 925-932
    Published: May 01, 1981
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    An isoperibol calorimeter used at steelmaking temperatures has been developed to measure the heat of mixing of liquid binary iron alloys (Fe-Co, Fe-Ni, Fe-Cu, Fe-Si and Fe-FeS). The experimental errors were less than ±15% for the values obtained.
    Heats of mixing in Fe-Co, Fe-Ni and Fe-Si were exothermic and their maximum values were -610, -1150 and -9000 cal/g·atom respectively. Mixing of Fe-Cu and Fe-FeS systems was an endothermic reaction having the maximum heats of 2400 and 1200 cal/g·atom respectively.
    The partial molar heats of mixing in these systems have been evaluated from the integral heats obtained in the present work by the assumption of f (XB)-functions.
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  • Toshiharu FUJISAWA, Yoshihiro ISHINO, Akio KUBO, Hiroshi SAKAO
    1981 Volume 67 Issue 7 Pages 933-939
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The activity of silicon in bcc-iron has been measured by means of the reaction
    SiO(g)+H2(g)Si+H2O(g).
    The measurements have been made at the temperature between 1400 and 1495°C for the composition of the stable bcc-phase.
    The activity coefficient of silicon at infinite dilution is logγosi(1)= -5.87 × 103/T+ 0.42 (1 4001 495°C)
    where pure liquid silicon is taken as the standard state, and logγosi (s) -3.23×103/T-1.15 (1 4001 495°C)
    where pure solid silicon is taken as the standard state.
    The interaction parameters of silicon are
    εsisi=5.39 × 104/T-19.97 (1 4001 495°C)
    esisi-465/T-0.177 (1 4001 495°C).
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  • Toshiharu FUJISAWA, Susumu KIMURA, Hiroshi SAKAO
    1981 Volume 67 Issue 7 Pages 940-945
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The equilibrium relationships between solid iron alloys and H2-SiO-H2O gas mixtures were measured at 1400°C, to investigate the effects of vanadium, chromium, molybdenum, and wolfram on the activity coefficient of silicon. The interaction parameters at constant silicon content rather than at constant silicon activity were determined as follows :
    εVSi =-3.4±1.1(Xv<0.052)
    εCrSi=0.05±0.6(XCr<0.11)
    εMoSi=1.8±0.4(XMo<0.031)
    εWSi=4.6+2.2(XW<0.017)
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  • Yukiyoshi ITOH, Tadaharu OKAJIMA, Hirobumi MAEDE, Kiyoshi TASHIRO
    1981 Volume 67 Issue 7 Pages 946-953
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    By preliminary tests for small ingots of Type 430 steel, the effect of electromagnetic stirring on refining of solidification structure was confirmed.
    A pair of linear-motor type stirrers was set in the slab caster and conditions of stirring and temperature of liquid steel in tundish for refining of solidification structure were investigated. By electromagnetic stirring of such a mode that directions of the two stirrers are same and are reversed every ten seconds, and by controlling the superheat of liquid steel in 15 to 25°C, equiaxed structure more than 50% in thickness of slab is secured and the ridging of cold sheet is improved.
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  • Osamu HAIDA, Shinobu OKANO, Toshihiko EMI, Goro KASAI
    1981 Volume 67 Issue 7 Pages 954-958
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    A semi-empirical attempt has been made to evaluate the formation of A-segregates in ingots as a function of the solute concentration in steel melts. Measurements on 22 ingots of the sum of the length of Asegregates(NA) found in unit area on the central longitudinal cross sections parallel to the narrow face of the ingots have given
    NA=1.43 (H/D)-0.42Tp+12.7Φ+2.3 (cm/100cm2)
    where H, D and Tp are height, width and taper of the ingot, respectively, and Φ is the difference in the density between bulk melt and solute enriched melt remaining in the mushy zone. In deriving the above empirical equation, Φ has been approximated by a linear function of the concentration, CoLn, of n-th solute in the bulk melt as
    Φ=-ΣInCoLn
    where theoretical consideration has enabled us to determine the value of the coefficient, In, for each solute element.
    The above equation for NA indicates that the movement activated by buoyancy of the remaining melt in the mushy zone plays a dominant role on the formation of A-segregates. This is confirmed by separate experiments where plate grade carbon steel with 0.043%silicon and 0.13%molybdenum has been cast in a 26 t mold, resulting in significant decrease of NA, about 1/4, in comparison with ingot of the same grade but with 0.34%silicon and no molybdenum.
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  • Natsuo HATTA, Jun-ichi KOKADO, Koichi HANASAKI
    1981 Volume 67 Issue 7 Pages 959-968
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The cooling process of a hot steel plate in the forced cooling of the laminar water flow was experimentally and analytically discussed. The main results obtained in this paper are as follows:
    1) The heat transfer coefficient α of the forced cooling of the laminar water flow can be deduced as "α=500·(θSW)1/2" where θS and θW are the temperature of the cooled surface and the cooling water, rerspectively.
    2) The radius RB of the circular black zone can be described as " RB= a√t" where t is the cooling time and a is the constant determined by the water flow rate and the vertical distance between a nozzle exit and cooled plate surface.
    3) The cooling curve calculated at a given point in the steel plate using the heat transfer coefficient indicated in 1) agrees with the experimental cooling curve when the water cooling diameter RW is assumed to be " RW=a√t+ 10".
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  • Chiaki OOUCHI, Tomoyoshi OOKITA, Sadahiro YAMAMOTO
    1981 Volume 67 Issue 7 Pages 969-978
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The effects of accelerated cooling after controlled rolling(CR) on the mechanical properties were investigated for the various microalloyed steels. The controlled rolling conditions were the reheating temperature of 1100°C or 1200°C, the cumulative rolling reduction of 70% below 900°C, and the finishing rolling temperature of 800°C with the plate thickness of 20 mm. The interrupted accelerated cooling (IAC) was carried out in the temperature range from 780°C to 600°C, followed by air cooling, and the maximum cooling rate was 12 °C/s. The increase of cooling rate in IAC caused the microstructural changes such as the refinement of ferrite grain size, disappearance of pearlite banding, and formation of refined bainite in place of pearlite. The increment of strength due to IAC with cooling rate around 10 °C/s that gave rise to the very refined duplex structure of ferrite and bainite was 5 to 10 kg/mm2, depending on the content of the microalloying elements such as Nb, V, or Ti. The Charpy transition temperature was improved by IAC under the reheating temperature of 1100°C, and the superior low temperature toughness such as the transition temperature below -100°C was attained with occurrence of very few separation on the fracture surface in Charpy impact test specimens. The optimum cooling conditions and the transformation behaviors in IAC were discussed. The increment of strength due to IAC was analyzed on the basis of the quantitative investigation of the transformed microstructure.
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  • Yoshifumi NAKANO, Michihiro TANAKA
    1981 Volume 67 Issue 7 Pages 979-996
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Crack arrest tests such as compact, ESSO and DCB tests were made on SA533B Cl. 1, HT80 and KD32 steels to evaluate the crack arrest toughness. The main results obtained are as follows:
    1) The crack arrest toughness was evaluated by KIa which was obtained by the static analysis of compact test.
    2) KID determined by the dynamic analysis of compact test was greater than KIa, though KID became close to KIa as KIa/KQ became a unity. KQ is the stress intensity factor at the crack initiation.
    3) No significant difference was observed between KIa and Kca obtained by ESSO and DCB tests, though Kca, obtained by DCB test tended to be smaller than KIa at lower temperatures.
    4) KIa was smaller than KIc in the transition temperature range, while it was greater than KId. In the temperature range where KIc which was determined from JIC decreased with temperature increase, however, it was smaller than KIa.
    5) The fracture appearance transition temperature and the absorbed energy obtained by 2 mm V notch Charpy test were appropriate parameters for representing the crack arrest toughness, while the NDT temperature was not.
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  • Yoshihiro KONDO, Takashi MATSUO, Takayuki SHINODA, Ryohei TANAKA
    1981 Volume 67 Issue 7 Pages 987-995
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Steady state creep rates and friction stresses based on the strain dip test were measured at 1 000°C with a series of carbon free 25Cr-35Ni austenitic steels, and the solid solution strengthening with the additions of groups IV, V and VI elements to the steel was discussed in terms of friction stress. The steady state creep rate of the steel decreased remarkably with the increase of Mo, W, Nb, Ta, Zr and Hf contents, but slightly decreased with the additions of Cr and Ti. Friction stress increased remarkably with the additions of Mo, W, Nb, Ta, Zr and Hf, and, therefore, the changes in the steady state creep rate with the additions of these elements was found to be quite similar to that in the effective stress (=applied stress minus friction stress). A single linear relation was found to exist between logarithms of the steady state creep rates and the effective stresses of all the steels independent of the kinds and the amounts of additional solute elements. The results conclusively demonstrate that the solid solution strengthening at the high temperature due to the additions of Cr, Mo, W, Nb, Ta, Ti, Zr and Hf to the carbon free 25Cr-35Ni austenitic steel is mainly attributed to the increase in the friction stress.
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  • Masayuki YOSHIBA, Ohmi MIYAGAWA, Dai FUJISHIRO
    1981 Volume 67 Issue 7 Pages 996-1005
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Hot corrosion behavior of various commercial heat resisting alloys was investigated at 800 and 900°C by means of furnace test using synthetic ash mixture composed of 90%Na2SO4 plus 10%NaCl. Ranking of alloys for corrosion resistance evaluated by furnace tests generally coincided with that of the corresponding alloys in combustion rig tests carried out by other researchers.
    Furnace tests showed that nickel-base alloys containing about 20% Cr exhibited most superior resistance to corrosion and nickel-iron-base, cobalt-base, iron-base and lower Cr bearing nickel-base alloys were more corroded in this order. Hot corrosion caused readily intergranular penetration in most of these alloys. The very poor corrosion resistance of low Cr-nickel-base alloys were responsible for the severe intergranular penetration as well as surface attack. It was also found that Cr, Co and Fe had beneficial effect on the corrosion resistance of nickel-base alloys, while the detrimental effect of Mo was less pronounced. As regards the effect of Ni, there existed an optimum content of about 40 to 50%. In Inconel 751 alloys subjected to hot corrosion, the intergranular penetration progressed in a parabolic rate law and the temperature dependence of the parabolic rate constant changed at about 780°C. An extremely low activation energy at the range above this transition temperature suggested that some liquidous corrosion products such as Ni3S2-Ni eutectic took part in the hot corrosion process.
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  • Susumu HORIBE, Masae SUMITA, Iku UCHIYAMA
    1981 Volume 67 Issue 7 Pages 1006-1014
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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    A study has been made of the microstructure and toughness of the heat affected zone (HAZ) in 5%Ni-0.5%Mo steels with the original structures of which were tempered martensite and bainite.
    These properties depend strongly on carbon contents in steels and cooling rate after rapid heating to 1350°C. With decreasing in the cooling rate the microstructure changes from martensite to bainite, and the increase of carbon content tends to retard this change. However, the optimum toughness is obtained in duplex structure of martensite and lower bainite regardless of carbon content. The microstructure and toughness of the partially-transformed region in HAZ are affected by original microstructures, since the aspect of austenitization is different in them. When the original microstructure is tempered martensite, the aspect depends on the tempering temperature and carbon content. On the other hand, when the structure is bainite, it depends on the roughness of the ferrite lath structure which is related to carbon content.
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], Seiji FUJI ...
    1981 Volume 67 Issue 7 Pages 1015-1025
    Published: May 01, 1981
    Released on J-STAGE: January 18, 2010
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  • Koji SHIBATA
    1981 Volume 67 Issue 7 Pages 1026-1029
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • [in Japanese]
    1981 Volume 67 Issue 7 Pages 1029-1029,1032
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1981 Volume 67 Issue 7 Pages 1035-1039
    Published: May 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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