Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 67 , Issue 16
Showing 1-22 articles out of 22 articles from the selected issue
  • Toru ARAKI
    1981 Volume 67 Issue 16 Pages 2573-2579
    Published: December 01, 1981
    Released: January 19, 2010
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  • Katsuya IKAWA
    1981 Volume 67 Issue 16 Pages 2580-2589
    Published: December 01, 1981
    Released: January 18, 2010
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  • Kenji HIRAKAWA, Kazuo TOYAMA
    1981 Volume 67 Issue 16 Pages 2590-2596
    Published: December 01, 1981
    Released: June 19, 2009
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  • Junji KIHARA, Tatsuhiko AIZAWA
    1981 Volume 67 Issue 16 Pages 2597-2602
    Published: December 01, 1981
    Released: June 19, 2009
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  • Kiichi NARITA
    1981 Volume 67 Issue 16 Pages 2603-2621
    Published: December 01, 1981
    Released: June 19, 2009
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  • Shuji OKITA
    1981 Volume 67 Issue 16 Pages 2622-2624
    Published: December 01, 1981
    Released: June 19, 2009
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  • Yukihiro HIDA, Minoru SASAKI, Kaoru ITO, Tuneo ENOKIDO
    1981 Volume 67 Issue 16 Pages 2625-2634
    Published: December 01, 1981
    Released: June 19, 2009
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    Combustion of coke particles in the fixed bed with mixed small alumina balls was investigated. NO decreased and CO was actively formed with increasing the heat supply. When exothermic material was used instead of the alumina ball NO decreased remarkably.
    According to the results of sintering pot tests, it was showed that the retardation effect for NO formation by increasing the heat supply with increasing the coke content in the raw mix and the fuel gas amount for ignition was smaller than that by using an ore containing less amount of combined water and an exothermic material. The NO conversion ratio in the former case was 0.07 and in the latter 0.24%/kcal/kg-raw mix. These values were almost similar to those obtained from the sintering machine operation investigated after these sintering tests.
    As a result of investigations on NO reduction in the sintering bed, the degree of NO reduction with CO in the bulk gas and coke particles was indicated to be smaller than 5-15%. The main effect for retardation of NO formation by the heat supply was proved to depend on the increase of CO/O2 around the burning coke particles.
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  • Kenji TAMURA, Katsuya ONO, Nobunao NISHIDA
    1981 Volume 67 Issue 16 Pages 2635-2644
    Published: December 01, 1981
    Released: June 19, 2009
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    For the purpose of determining optimum operating conditions for the refining processes of iron and steel making, transfer reactions of silicon and sulphur into pig iron were studied from the kinetic and thermodynamic points of view, and general estimation equations were derived concerning contents of silicon and sulphur in pig iron. The results obtained were summarized as follows :
    ( 1 ) Simulation was carried out by making use of actual operating data of thirteen blast furnaces whose operating conditions were different with regard to inner volume, production rate, fuel rate, and so forth, and it was confirmed that the equations in the present paper agreed approximately with the actual ones.
    ( 2 ) It was clarified that actual contents of silicon and sulphur in pig iron were nearly the equilibrium ones on the assumption that the partial pressure of CO generated in the layers of slag and pig iron was much the same as blast pressure.
    ( 3 ) Main operating factors exerting influence on the silicon content in pig iron were blast pressure, pig iron temperature, slag composition (basicity, contents of MgO and Al2O3 ), and pig iron composition (contents of C and Mn), and the effects of these factors on the silicon content were evaluated quantitatively.
    ( 4 ) Kinetic analysis as to the silicon transfer from SiO gas to molten pig iron in the region of blast furnace tuyeres indicated that besides the factors described above (3), the silicon content would be influenced by production rate and the dropping distance between a tuyere level and an inner edge of a cohesive zone.
    ( 5 ) Main operating factors exerting influence on the sulphur content in pig iron were blast pressure, total input sulphur, pig iron temperature, slag rate, slag composition (basicity contents of MgO and Al2O3) and pig iron composition (contents of C and Si), and the effects of these factors on the sulphur content were evaluated quantitatively.
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  • Hideaki SUITO, Ryo INOUE, Minoru TAKADA
    1981 Volume 67 Issue 16 Pages 2645-2654
    Published: December 01, 1981
    Released: May 07, 2010
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    Experiments have been made to study the phosphorus distribution between liquid iron and the CaO-MgO-FeOx-SiO2 slag equilibrated in a magnesia crucible in the temperature range 1 550-1 650°C. The phosphorus distribution ratio (P2O5)/[P] increased with increasing CaO content and decreasing temperature. The maximum values of the distribution ratio were found to be present near the slag composition saturated with the tricalcium silicate and the magnesio wustite phases. The experimentally determined phosphorus content in metal disagreed with the phosphorus content estimated from the treatments proposed by Balajiva et al., Turkdogan and Pearson, and Healy over the present range of slag compositions, except by Flood and Grjotheim.
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  • Yasuhisa OZAWA, Kazumi MORI, Masamichi SANO
    1981 Volume 67 Issue 16 Pages 2655-2664
    Published: December 01, 1981
    Released: June 19, 2009
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    Nitrogen (0.054 500 cm3/s) was injected into a mercury bath through an orifice of 0.10.4 cm in diameter located at the transparent vessel bottom. The highest gauge pressure supplied to the system was 20 kgf/cm2. Behavior of gas jets at the orifice was observed directly through the bottom plate by using a high speed cinecamera.
    At gas-flow rates lower than the critical rate described below, the jet is shown to expand immediately upon discharging and form seemingly discrete bubbles of various sizes. This behavior is called "bubbling". With increased gas-flow rates, an apparent coincidence between the bubble base diameter and the orifice diameter begins to occur over various time ranges. It is presumed that in these time ranges a continuous gas jet forms at the orifice. This phenomenon is called "jetting". It is found that the value of the critical gas-flow velocity at which the transition from bubbling to jetting begins to occur is independent of the diameter of the orifice and a little bit higher than but very close to the sonic velocity. With increasing gas-flow rate jetting fraction increases and bubbling fraction decreases.
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  • Takao CHOH, Takashi TAKEBE, Michio INOUYE
    1981 Volume 67 Issue 16 Pages 2665-2674
    Published: December 01, 1981
    Released: June 19, 2009
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    The rates of nitrogen desorption of liquid Fe-Cr alloys up to 25% Cr were measured under the reduced pressure at 1 600°C.
    The rates of nitrogen desorption of liquid Fe-Cr alloys are apparently expressed by the equation of 2nd order reaction in terms of nitrogen content in melts, as shown in the case of the nitrogen desorption of liquid iron, and the rate constant obtained decreases with increasing chromium and oxygen contents. The results are explained by the application of the mixed-control model including the resistances of the mass transfer in the liquid phase and that at the interface where the nitrogen atom transfers into the gas phase only through the effective sites determined by the adsorption equilibrium.
    The contributions of the resistance of the mass transfer in the liquid phase and the interfacial resistance to the nitrogen desorption process were considered. The mass transfer in melt may play an important role on the nitrogen desorption at the lower chromium and lower oxygen levels. On the other hand, at higher chromium content, the contribution of the interfacial resistance becomes important even if the oxygen content is low, because the activity coefficient of nitrogen decreases.
    The effect of the air leak in the vacuum reaction chamber on the rate of nitrogen desorption is considered by using the present experimental results. It is suggested that, at higher chromium contents, the nitrogen desorption is remarkably retarded in the presence of a small amount of air leak.
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  • 1981 Volume 67 Issue 16 Pages 2674-2674,2699
    Published: December 01, 1981
    Released: June 19, 2009
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  • Yukiyoshi ITOH, Singo SATOH, Yuji KAWAUCHI
    1981 Volume 67 Issue 16 Pages 2675-2684
    Published: December 01, 1981
    Released: June 19, 2009
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    New process "SMP" (Slag Minimum Refining Process) which consists of hot metal desiliconization stage in hot metal containner and dephospharization and decarbarization stage in LD converter has been studied in order to reduce the consumption of refining fluxes and slag volume yield in conventional LD process.
    After experimental studies which have been carried out in KR equipment and conventional LD converter to estimate the feasibility of this new process, it was cleared that hot metal desiliconization treatment can be done with simple equipment by using proper desiliconization agent and flux and its proper adding method.
    By this new process, CaO consumption for dephosphorization in LD converter and slag volume can be reduced drastically with decreasing Si content in hot metal and that CaO consumption and slag volume required is 18 kg/t.s, 42 kg/t.s at Si=0.15% by low carbon rimmed steel. As a result of it, linning life of refractory can be extended and the amount of metal and heat loss can be decreased and it makes the LD refining very stable.
    Based on the results obtained by the above experiments, a practical equipment of hot metal desiliconization treatment has been installed and came in use in October 1979. and now is in a stable operation.
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  • Ichiro IMAI, Kazutoshi KAKITA, Mitsuo NARAZAKI, Yoshitaka AMANO
    1981 Volume 67 Issue 16 Pages 2685-2691
    Published: December 01, 1981
    Released: June 19, 2009
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    Geometrical and physical factors having effects on the circumference of spiral pipe have been investigated experimentally. Geometrical factors such as weld seam gap, swing angle of pipe by gap controlling system and especially camber of coil after trimming have big effects on it. In order to avoid the camber after trimming, a coil walk control system has been developed and the accuracy of circumference is much improved by it. Physical factors such as yield strength of hot rolled coil and deflection of coil by forming rolls (δ) have no direct influences on it but big influences on residual stress of pipe. The change of residual stress of pipe causes a change of geometrical factors such as seam gap and/or forming angle and leads to the pipe circumference deviation. Therefore the δ must be kept constant in spiral pipe forming operation.
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  • Tetsuo KATO, Masakuni FUJIKURA, Shin-ichiro YAHAGI
    1981 Volume 67 Issue 16 Pages 2692-2699
    Published: December 01, 1981
    Released: June 19, 2009
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    In order to develop new austenitic manganese steels for structural nonmagnetic and wear resistant applications that have almost same mean thermal expansion coefficient as carbon steel in the temperature range between 0°C and 100°C, an investigation has been made of the effects of various alloying elements, C, N, Cr, Mn, on the thermal dilatation curve and Neel temperature that is found from the temperature dependence of the magnetization. The results obtained are as follows :
    Mean thermal expansion coefficient α of austenitic manganese steels increases with increasing content of C and N, while it decreases with increasing manganese content. α vs. Cr content curve shows a minimum value. Following linear regression equation that relates α to the chemical composition is obtained.
    α(×10-6/°C)=19.72+2.32(%C)+1.39(%N)-0.31(%Mn)
    +0.028(%Cr)2-0.41(%Cr)+0.14(%ε')
    where, (%ε') represents the volume percent of HCP ε' martensite. The effects of alloying elements on the Néel temperature show a reverse tendency comparing with those on α. It is also found that α tends to decrease with raising Néel temperature. The dependence of the α below Néel temperature on chemical composition can be estimated by the change resulting from substantially the variation of spontaneous volume magnetostriction by alloying.
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  • Yasutaka OKADA, Tatsuro KUNITAKE
    1981 Volume 67 Issue 16 Pages 2700-2709
    Published: December 01, 1981
    Released: January 18, 2010
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    A maraging steel of 17.5%Ni-6%Mo-12.5%Co-1%Ti shows superior ductility and toughness at ultrahigh tensile strength level after conventional heat treatment (solution treatment and aging). In steels with higher nickel content from 19% to 24% to the above mentioned base composition, austenite is retained at room temperature after solution treatment due to lowering of Ms temperature. The high nickel maraging steels with retained austenite show various microstructures (lath martensite, lenticular martensite and untransformed austenite) after cold rolling or sub-zero treatment. Relation between ductility, toughness and various microstructures is discussed.
    Principal results are as follows :
    1) Retained austenite, formed owing to the increase of nickel content, transformed to lath martensite after cold rolling at room temperature. In alloys with 100% lath martensite structure obtained from above treatment, the beneficial effect of nickel on the increase of strength and toughness was confirmed up to 20%.
    2) Retained austenite had no effect on the ratio of notched tensile strength to tensile strength after aging.
    3) Lenticular martensite was observed in the steels with the nickel content of more than 20% after sub-zero treatment. Lenticular martensite was ascertained to decrease toughness remarkably after aging.
    4) Cold rolling in the range of reduction of area from 30% to 60% was effective to increase toughness. The maraging steel with 20% nickel, cold rolled with the reduction of area of 60%, had the tensile strength of 2 700 MPa with the ratio of notched tensile strength to tensile strength of more than 1.0.
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  • Motohiro OKADE, Masaharu TOKIZANE, Oleg. D. SHERBY
    1981 Volume 67 Issue 16 Pages 2710-2714
    Published: December 01, 1981
    Released: May 07, 2010
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    An ultra-fine-grained SUJ-2 steel was obtained by applying one of thermomechanical processing routes developed in UHC-steel. This material showed the high elongation-to-failure values of 400840% at warm temperature between 650 and 730°C over a range of initial strain rates from 1 x 10-4 sec-1 to 8 × 10-4 sec-1. The value of m≅0.33 and the activation energy of 195 kJ/mol was obtained for the deformation process in this range. From these results, it could be concluded that grain boundary sliding is not totally dominating the deformation process of the present material although superplastic flow plays an important role in the region studied.
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  • Toshio TERASAKI
    1981 Volume 67 Issue 16 Pages 2715-2723
    Published: December 01, 1981
    Released: June 19, 2009
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    This report deals with the relationship of welding conditions, such as cooling times, chemical compositions, vs. the maximum hardness at the neighbourhood of bond line in the heat affected zone and the thermal factor, which is connected with the residual diffusible hydrogen content accepted welding thermal cycle, being main factors for cold cracking. Relationships of thermal factor and hardness vs. cooling times and chemical compositions are not able to be shown as function formulae. Therefore, the regression equations are derived by the stagewise regression analysis from many data of thermal cycles and CCT diagrams containing hardness data. The results are summarized as following :
    (1) The predicted value (∑DΔt)100of thermal factor is connected with cooling times by following formula.
    (∑DΔt)100= (4.2t200+2.73t150-13) × 10-5(cm2)
    tθ; cooling time from melting temperature to θ°C at the neighbourhood of bond line (sec)
    (2) The relationship of predicted value of hardness Hv vs. cooling time and chemical compositions is estimated by following formula.
    τ≤τM Hv=812C+293
    τ>τM Hv=(992C-230Pv+250) exp {-3t800500/(310)Pv}+188Pv+80
    where τ = t 800500; cooling time from 800°C to 500°C at the bond line log τM= 2.5Pv-1.21
    Pv=C + Mn/3+Ni/8+ Cr/12+ Mo/2+Cu/5
    The unit of chemical compositions is weight %.
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  • Kiichi NARITA, Masayuki TANIGUCHI, Noriaki OTA, Renpei MOROOKA
    1981 Volume 67 Issue 16 Pages 2724-2733
    Published: December 01, 1981
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    A sensitive spectrophotometric method has been developed for the determination of microamounts of sulfur in iron and steel.
    The sample is dissolved in hydrochloric and nitric acids thus converting sulfur to sulfate. After removing nitric acid by heating with perchloric acid the sulfate is reduced with a mixture of hydriodic and hypophosphorus acids, and the hydrogen sulfide evolved is determined spectrophotometrically as methylene blue. For trace amounts of sulfur below 5 ppm, in order to increase the sensitivity of the method the methylene blue is furthermore extracted into dichloroethane as the ion pair with perchlorate.
    The proposed method is applicable to a wide variety of iron and steel samples although a slight modification is required when the sample contains selenium, titanium, niobium and tantalum. The range of determination is 0.5 to 100 ppm using 0.5 g sample the standard deviations at the 50 and 2 ppm levels are 0.7 and 0.1 ppm, respectively.
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  • Morito NAKAZAWA
    1981 Volume 67 Issue 16 Pages 2734-2738
    Published: December 01, 1981
    Released: January 18, 2010
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  • [in Japanese]
    1981 Volume 67 Issue 16 Pages 2741-2743
    Published: December 01, 1981
    Released: June 19, 2009
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1981 Volume 67 Issue 16 Pages 2751-2755
    Published: December 01, 1981
    Released: June 19, 2009
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