Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 80 , Issue 4
Showing 1-18 articles out of 18 articles from the selected issue
  • Chiaki TANAKA, Koichi YAGI
    1994 Volume 80 Issue 4 Pages 255-262
    Published: April 01, 1994
    Released: January 18, 2010
    JOURNALS FREE ACCESS
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  • Takahiro KUSHIDA, Hiroo OHTANI
    1994 Volume 80 Issue 4 Pages 263-269
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
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  • Takazo KAWAGUCHI, Yasuhiko HADANO, Tatunori MURAI, Yoshizumi KAWAGUCHI
    1994 Volume 80 Issue 4 Pages 270-275
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Pisolite is an important raw material for sinter ore because its deposit in Australia is rich and easy to be explored. This ore is mainly made of goethite with a oolitic structure. After produced as lumpy ore, it is crushed to be a raw material for sinter ore, however, pisolite is known to have negative effects on sintering process. For a better use of this material, we propose a process to use lumpy pisolite ore as a hearth material in sinter plants. Our pot tests showed that this, process has a higher productivity and yield, compared with the conventional process that uses sinter ore as a hearth material and fine pisolite as a raw material for sinter. A 1.5-day test in our commercial sinter plant and blast furnace in Kokura also showed that this new process enables more use of cheap pisolite and reduces the energy consumptior in sintering process.
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  • Sengli WU, Takeshi SUGIYAMA, Kouichi MORIOKA, Eiki KASAI, Yasuo OMORI
    1994 Volume 80 Issue 4 Pages 276-281
    Published: April 01, 1994
    Released: January 19, 2010
    JOURNALS FREE ACCESS
    Since equipment, built to eliminate the NOx gas in the off gas of iron are sinter plant, is huge inci expensive, it is desirable that a more simple and economical method to eliminate the NO gas is established.
    The method to eliminate the NO gas near the coke in the iron are sinter bed has been studied. As a basic study on NO elimination reaction, the reaction characteristics between NO gas and the heated iron oxide at each oxidation grade or calcia-iron oxide compound under the atmosphere with or without CO/CO2 have been investigated.
    It became clear that the iron oxide with lower oxidation grade accelerates to decrease the NO gas concentration in the off gas and that the co-existence CO gas also decreases it with the effect of lowering the oxidation grade of iron oxide.
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  • Eiki KASAI, Takeshi SUGIYAMA, Yasuo OMORI
    1994 Volume 80 Issue 4 Pages 282-287
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Combustion experiments of packed bed were carried out using compacts of powder mixtures of metallic iron and coke, and coke prepared by admixing of iron are with the raw materials, in order to verify an effect of the existence of metallic iron and/or the lower oxides of iron in the vicinity of burning coke particles on the reduction of the amount of nitrogen oxides emission. Conversion ratio of N in coke into NOx decreased by about 20% during combustion of the compacts containing 10 mass% of metallic iron, comparing to that without metallic iron. Content of N in the coke prepared by admixing of iron are lowered more than the value estimated from the mixing proportions of the raw materials. The results of the combustion experiments using such iron-bearing coke showed that the conversion ratio into NOx decreased by about 20 to 40% and the emission amount of NOx also reduced by 35 to 55% depending on the preheating temperature of samples.
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  • Tatsuro ARIYAMA, Michitaka SATO, Yu-ichi YAMAKAWA, Yoshiro YAMADA, Min ...
    1994 Volume 80 Issue 4 Pages 288-293
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Hot model experiments on pulverized coal injection were carried out to understand the combustion mechanism of pulverized coal injected into the blast furnace. The combustion behavior of the pulverized coal was directly observed by a high speed camera, and the temperature distribution of combustion flame was analyzed by an image processor. According to the results, the combustion flame was not uniform across the cross-section of blow pipe and tuyere, and the fluctuation of the flame was observed. Then, it was found that the dispersion of pulverized coal had a great role on combustibility owing to the rapid consumption of oxygen by the combustion of volatile matter. Moreover, it was confirmed that the arrangement of injection lance influenced on the combustion efficiency, since the dispersion of coal particles was settled by the injection lance. On the basis of the above results, the dispersion of coal particles was analyzed by the calculation of the average distance of individual coal particles to easily evaluate the effect of the lance arrangement.
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  • Katsumi MORI, Toshiro KITAHARA, Kunihiko NAKASHIMA
    1994 Volume 80 Issue 4 Pages 294-299
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    In order to clarify the kinetic behavior of dissolution of solid copper into liquid lead and aluminum, the change in radius of cylindrical copper specimen with time was examined under static or rotating condition in the temperature range from 500 to 900°C.
    It was found that the dissolution rate increases with increasing rotating speed. This fact supports that the diffusion of copper in a liquid metal is a rate-limiting step. As a result of kinetic analysis based on the film theory, the following non-dimensional correlation was obtained for each flow condition.
    Under rotating condition in lead melt,
    JD(=k/U·Sc2/3)=0.014·Re-0.13
    Under static condition in both melts,
    Sh(=k/D)=0.015·(Grm·Sc)0.44
    Apparent activation energies for dissolution were calculated to be about 10 kJ/mol at 200 rpm, and 35-40 kJ/mol for static condition. These values are comparable to those estimated from the temperature dependence of physical properties of liquid metals.
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  • Mitsutaka HINO, Shei-bin WANG, Tetsuya NAGASAKA, Shiro BAN-YA
    1994 Volume 80 Issue 4 Pages 300-305
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    The evaporation rate of Zn from liquid iron has been observed at 1873K for the fundamental study on mechanism of tramp element removal from remelted steel scrap. In the present work, iron containing Zn was inductively melted and Zn was evaporated by impinging argon gas onto the surface.
    The evaporation rate of Zn was found to be first order with respect to Zn content in the metal. No measurable effects of the argon flowrate and carbon or sulfur content in the metal on the rate were observed under the condition of argon flowrate above 51/min, but the evaporation rate was strongly affected by stirring condition of the melt. Therefore, it was concluded that the evaporation rate of Zn was controlled by the mass transfer in the liquid phase. The mass transfer coefficient in the liquid phase was estimated as 0.032 cm/s at 1873K. The removal rate of Zn in the vacuum treatment was also discussed based on the present result.
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  • Shigeta HARA, Takashi KOBAYASHI, Kazumi OGINO
    1994 Volume 80 Issue 4 Pages 306-311
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Stability of a single bubble made of soap-water solution, BaO-B2O3 melts and molten CaO-SiO2-Al2O3-MgO slags were studied under air. For very stable BaO-B2O3 bubble, it is found that tension of bubble lamella is higher than surface tension of the melt. Similar situation was also observed for soap-water solution. For molten slags, whose bubble is unstable, tension of the lamella is lower than surface tension of the melt, but P2O5 addition to the melt increased the tension of the bubble lamella and the bubble was slightly stabilized. Stabilization mechanism of the bubble lamella is discussed.
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  • Shoji TANIGUCHI, J.Keith BRIMACOMBE
    1994 Volume 80 Issue 4 Pages 312-317
    Published: April 01, 1994
    Released: January 19, 2010
    JOURNALS FREE ACCESS
    Application of the pinch force to the separation of inclusion particles from liquid steel flowing in a rectangular pipe was investigated theoretically. By impressing an electrical current in a liquid metal along the axis of the pipe, the metal will receive a pinch force and electrically nonconductive particles suspended in the metal will be squeezed out by this force. In the case of rectangular pipe, the pinch force is concentrated near the corner of the pipe at high frequencies, and as a result secondary flows may be generated in the cross section of the pipe. These flows will affect the particle-separation efficiency.
    Numerical calculations were made to obtain the pinch force, fluid flow and particle concentration. In the quarter section of the pipe, two recirculating flows were generated and their maximum velocity increased with increasing x1/ δ. Pipe Reynolds number, Re(=2x1w/ν), decreased rapidly after x1/δ exceeded a critical value which changed with C1(=μeIrms2/ρν2). The particle-separation efficiency, η, was a function of (C1DR2/Re)Z while the secondary flows are negligible. The value of η was found to increase with increasing x1/δ because of the development of the secondary flows. This result is a contrast to the case of circular pipe investigated in the previous study.
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  • Tadashi FURUHARA, Sachio SIIIMOHATA, Kenji WADA, Tadashi MAKI
    1994 Volume 80 Issue 4 Pages 318-323
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    The effect of ferrite substructure on precipitation of Fe3C at MnS in in Al-killed steel was studied. By heat treatment, dislocation density and grain size were varied under the presence of MnS particles. By the subsequent aging at 603K and 703K, the ratio of Fe3C precipitates nucleating on MnS with respect to the total number of Fe3C precipitates was lowered under the presence of a larger number of dislocations and grain boundaries. It was considered that a MnS particle is less effective than a dislocation, and is comparably effective with a grain boundary is t heterogeneous nucleation site of Fe3C in ferrite.
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  • Tetsuya TAGAWA, Syuuhei YAMAMOTO, Takashi MIYATA
    1994 Volume 80 Issue 4 Pages 324-329
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Influence of the weld oxides on the ductility and fracture toughness of the elect ric resistance welded joint of steel pipewas investigated. Experiments were performed for round bar tensile tests and three point bend COD test. With the increase of the oxides zone area which was defined by fracture appearance, the ductility in the smooth and the notched bar specimens, and the fracture toughness were gradually decreased. Fractographic examination showed a good correlation between the stretched zone depth in COD specimen and the dimple size at the oxides zone. Finally, the validity of engineering evaluation method for the weld oxides was discussed.
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  • Keishi NAKANO, Takashi YASUNAKA
    1994 Volume 80 Issue 4 Pages 330-335
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    The objective of this study is to characterize the behavior of dynamic fracture toughness of a thick-walled ferritic spheroidal graphite iron and to evaluate this material for unstable fracture.
    Unlike static elastic-plastic fracture toughness JIc, the distribution of graphite nodule has a very slight effect on the upper shelf dynamic elastic-plastic fracture toughness JId. Upper shelf fracture toughness increases with increase in stress intensity rate K. This increase in fracture toughness is mainly attributed to increase in strength at high rate of K.
    Ductile-brittle transition temperature is linearly related to the logarithm of K. In the upper shelf region, converted plane strain fracture toughness divided by yield strength can be adopted as a material constant that is independent of K and temperature. On the basis of the JIC-temperature curve and the results of impact bending tests on small size specimens, it can be made to estimate the behavior of JId as for temperature and the predetermined K.
    In the upper shelf region of the material investigated, the maximum allowable surface flaw depth exceeds the minimum detectable flaw size by a nondestructive inspection. Ferritic spheroidal graphite iron can be used as a material for casks in the upper shelf region at least.
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  • Kouichi MARUYAMA, Eiji BABA, Kenji YOKOKAWA, Hideaki KUSHIMA, Koichi Y ...
    1994 Volume 80 Issue 4 Pages 336-341
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    Long term creep rupture life has been estimated from short term data by the extrapolation based of the timetemperature parameter (TTP) methods. This work aims at discussing causes of the extrapolation error. Temperature dependence of rupture life can change at longer lives due to the change in fracture mechanism. The present forms of TTP, however, do not take the change into account, and this disregard is responsible for the extrapolation error. When the change occurs, one cannot correctly extrapolate rupture life even less than three times the longest test duration.On the other hand, rupture life can be extrapolated more than ten times without introducing a serious error when thechange is absent. The change in temperature dependence also influences the direction of deviation from true values.The extrapolation provides a conservative estimate when the temperature dependence of rupture life increases at longer lives, whereas it gives a nonconservative estimate when the dependence decreases.
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  • Takuya YASUNO, Akio KOGANEI, Kazuhiko KURIBAYASHI, Tadashi HASEGAWA, R ...
    1994 Volume 80 Issue 4 Pages 342-347
    Published: April 01, 1994
    Released: January 18, 2010
    JOURNALS FREE ACCESS
    Effect of various bolide former elements on recovery and recrystallization of reverse-transformed austenite was examined in carbon-free Fe-19mass%Ni alloys. The combined addition of Nb and B was found to be most effective in suppressing them, because the recrystallization of reverse-transformed austenite rose up to 1200K, which was 100K higher than that of nothingadded alloy. TEM observation of extraction replicas indicated that their retardation was due to very fine precipitates of Nb-bolide. It was evident from the theoretically obtained solubiliy products of several MB2-type bolides (M:Cr, Mn, Nb, Ti, Mo) that NbB2 was more stable than the other bolides up to high temperature. This may be the reason why recovery and recrystallization are suppressed up to the highest temperature by the combined addition of Nb and B.
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  • Kiyoshi KUSABIRAKI, Itaru HAYAKAWA, Shuuichi IKEUCHI, Takayuki OOKA
    1994 Volume 80 Issue 4 Pages 348-352
    Published: April 01, 1994
    Released: January 18, 2010
    JOURNALS FREE ACCESS
    The morphology of γ″ precipitates extracted from a nickel-base superalloy, a modified Inconel 718 type alloy (718M), was investigated mainly by transmission electron microscopy (TEM). The TEM images using carbon extracted replica of γ″ precipitates were clearer than those using electropolis. hed thin film. The γ″ precipitates were disc-shaped in the early stage of aging and became rectangular-shaped plates in latter at up to 1033K, while they grew in 'propeller'-shaped plates with preferential growth along <110>γ″ directions in latter at 1073K. The morphology changes of the γ″ precipitates with the increase in aging time and temperature were dependent not only on the size of them but also on the chemical composition of the alloy.
    The internal fringe contrast due to stacking faults on {112} plane of γ″ phase was not observed in the γ″ precipitates in the 718M unlike in a Ni-15Cr-8Fe-6Nb superalloy previously reported.
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  • Keiji UEDA, Yasuaki SUGIZAKI, Takashi YASHIKI, Hiroshi SATOH
    1994 Volume 80 Issue 4 Pages 353-358
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
    General corrosion and crevice corrosion behaviors of titanium alloys, Ti-Ni-(Pd, Ru)-Cr and Ti-Cr have been investigat-ed in comparison with the unalloyed titanium. The specimens of the alloyed and unalloyed titanium were subjected to conventional immersion test in hydrochloric acid solutions and a concentrated chloride solution at elevated tempera-tures. Electrochemical properties of the alloys were also measured in order to understand the effect of chromium addition on the corrosion behaviors.
    The results have indicated that an excellent improvement in general corrosion and crevice corrosion resistance is attained by chromium addition with nickel, palladium and ruthenium. However, a single addition of chromium deteriorates the corrosion resistance of titanium in hydrochloric acid solutions. The corrosion kinetics for the alloys is discussed in terms of the compositional change on the corroded surface during the corrosion process. An excellent corrosion resistance of Ti-Ni-(Pd, Ru)-Cr alloy is considered to be originated from enrichment of palladium and ruthenium, which is promoted by chromium addition.
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  • Koki GUNJI
    1994 Volume 80 Issue 4 Pages N176-N186
    Published: April 01, 1994
    Released: June 19, 2009
    JOURNALS FREE ACCESS
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