Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 72 , Issue 16
Showing 1-20 articles out of 20 articles from the selected issue
  • Kiminari KAWAKAMI
    1986 Volume 72 Issue 16 Pages 2153-2168
    Published: December 01, 1986
    Released: February 16, 2010
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  • Sen-ichi HARIMAYA
    1986 Volume 72 Issue 16 Pages 2169-2175
    Published: December 01, 1986
    Released: June 30, 2009
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  • Tadayoshi TAKAHASHI
    1986 Volume 72 Issue 16 Pages 2176-2186
    Published: December 01, 1986
    Released: June 30, 2009
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  • Yoshifumi NAKANO
    1986 Volume 72 Issue 16 Pages 2187-2193
    Published: December 01, 1986
    Released: June 30, 2009
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  • Hideyuki Yamaoka
    1986 Volume 72 Issue 16 Pages 2194-2201
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    In order to evaluate the effect of powder on the blast furnace operation, the 2-dimensional behavior of gas and powder in packed bed with a tuyere on it's wall side were studied by a mathematical simulation model as well as a cold model experiment. Results obtained are as follows;
    1) When the gas velocity along the wall side is decreased, powder tends to accumulate near the wall above tuyere resulting in the increase in pressure drop of gas and the decrease in gas flow rate near the wall.
    2) The deterioration of gas permeability accompanied by the decrease in wall temperature at the lower part during the reduced production operation of blast furnace can be attributed to the accumulation of fine coke near the wall.
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  • Kuniyoshi ISHII, Oshiaki KASHIWAYA, Hideyoshi YAMAGUTI, Shin-ichi KOND ...
    1986 Volume 72 Issue 16 Pages 2202-2209
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    A hybrid blast furnace simulator has been developed on the basis of mathematical model and experiments by combining differential fixed-bed reactor and micro computers. Assuming that the burden and gas phase moved counter-currently in the blast furnace, the experimental conditions were calculated in real time by putting in situ measured rates of reduction and solution loss to the differential equations of mass and heat balance, and the new experimental conditions were set at next stage. The simulation was performed by repeating the sequence.
    (1) If simulation conditions were set up so as to fit the burdens, the simulation successfully proceeded and the longitudinal distribution of process variables in B.F. could be expected precisely according to the reactivity of burdens.
    (2) When the operations with pellet and sinter were simulated, thermal reserve zone was longer and smelting reduction began at lower temperatures for the former than for the latter.
    (3) With lower coke rate, reduction hardly proceeded and burden was heated up during short descending. On the other hand, with higher coke rate, although reduction proceeded fast, burdens remained at low temperatures.
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  • Shiro BAN-YA, Yasutaka IGUCHI, Seiji YAMAMOTO
    1986 Volume 72 Issue 16 Pages 2210-2217
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    The solubility of water vapor and the rate of water vapor dissolution in liquid CaO-SiO2-MgO and CaO-SiO2-TiO2 slags have been measured by a sampling method.
    The solubilities of water in slags at 1 450°C were shown with water-vapor capacity, defined by log K'=log {(%H2O)sPH2O}.
    The water vapor dissolution in these liquid slags would be controlled by diffusion of H2O in the bulk slag the same as in the CaO-SiO2-Al2O3 system. The apparent diffusion coefficient of water vapor, DH2O, was evaluated and the effects of slag composition, such as basicity, MgO or TiO2 content and temperature on DH2O were discussed.
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  • Shigeo ASAI, Toshiyuki KOZUKA, Iwao MUCHI
    1986 Volume 72 Issue 16 Pages 2218-2224
    Published: December 01, 1986
    Released: June 30, 2009
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    A new process of horizontal electromagnetic casting (HEMC) described as non-mold casting is proposed in which the molten metal is levitated by imposing direct current and direct magnetic field. This process may be favorably applied to the casting of heavy metals, since strong electromagnetic force can be induced at the expense of a small quantity of electric energy. On the other hand, in case of the ordinary process of vertical electromagnetic casting (VEMC), a large amount of electric energy and cost of equipment are indispensable for casting a heavy metal. By using this process, the alloy of 56%Bi-40%Sn-4%Zn (M.P.=403 K, ρ=8.7×103 kg/m3) was cast to simulate the casting of molten steel, and the surface defects arising by the metal-mold contact could be eliminated.
    Furthermore, the stability analysis is developed to confirm the applicability of this process and to determine the stable operating conditions.
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  • Kunihiko ONISHI, Kunio NAGAI, Toshie HASHIMOTO
    1986 Volume 72 Issue 16 Pages 2225-2232
    Published: December 01, 1986
    Released: June 30, 2009
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    Concerning a high speed continuous slab caster, strains in a slab were analyzed and a state of loads act on rollers was discussed. From this analysis, the followings were elucidated:
    1) The maximum strain in a slab caused by bulging is the component in the casting direction on a inner surface of a shell in a broad side of a slab just under a roller.
    2) The allowable roller pitch to prevent internal cracks of a slab caused by bulging becomes much smaller as a temperature of a slab becomes higher. But the influence of a casting speed on the allowable roller pitch is small.
    3) Straightening strains in a slab advance not along a designed radius of a machine but along a curvature defined geometrically by a roller arrangement, and the variation of strains of a slab is not linear in a roller pitch and in some cases strain rate becomes very large.
    4) For high speed casting, multi-straightening is necessary to prevent internal cracks of a slab caused by straightening strains.
    Further, using the results of this investigation, a method of the decision of proper arrangements and constructions of rollers to prevent internal cracks of a slab was systematized.
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  • Takayuki KOYANO, Yusuke SHIRATANI, Shigetaka UCHIDA, Tsutomu WADA, Tos ...
    1986 Volume 72 Issue 16 Pages 2233-2239
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    The slab caster No.5 was put into operation in September, 1984 at NKK Fukuyama Works, which was directly connected with the hot strip mill No.2 for the purpose of Hot Direct Rolling Process (HDR).
    To realize the HDR this caster is provided with various automatic facilities and with several characteristics on operation such as mentioned below.
    (1) For high speed casting (over 2.0 m/min); low viscosity mold powder (lithium being added), nonsinusoidal oscillation, and mold copper plate, etc.
    (2) For high temperature slab discharging; heat insulating apparatus, secondary cooling with width control system, and slab edge heater.
    (3) For improvement of surface and inner quality of slab; accurate mold level control, optimum design of immersion nozzle, air mist cooling, etc.
    By these newly developed techniques the monthly production by the HDR process was increased up to 100 thousand tons of steel. This report describes the new facilities and the operation technologies developed for this HDR process.
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  • Chisato YOSHIDA, Kazuyuki TANIGUCHI, Tomokazu NAKAGAWA, Masatoshi SUDO ...
    1986 Volume 72 Issue 16 Pages 2240-2247
    Published: December 01, 1986
    Released: June 30, 2009
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    After the energy crisis the steel industry is required to minimize its energy consumption. Direct connection with a hot rolling process in continuous casting is one of the solutions for this problem. Furthermore along with the developments of the continuous casting process, new casting processes are presently under development with the objective of eliminating most parts of the rolling and heating processes.
    As the solidification rate of the rapidly solidified plate in the new casting processes is 100103°C/s, the properties of the cast plate are expected to be improved. As the first step in our experiment, the properties of cast iron and high carbon steel were investigated.
    Thin sheets of cast iron were made by the twin roll test caster and cold rolling. Cold rolling was attainable due to the fine spheroidal graphite structure formed by the rapid solidification and the following annealing.
    Furthermore, rapid solidification of high carbon steel was investigated by using the water-cooled chill block apparatus, which was supposed to function similarly to a caterpillar type caster. The rapid solidification promoted less macrosegregation and finer MnS inclusions.
    It is well known that in the high carbon steel, the heat treatment is necessary for spheroidizing the cementite structure. It was proved, however, by the rapid cooling at eutectoid temperature, the spheroidal cementite structure was obtained in a relatively shortened annealing time.
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  • Kazuo OHMORI, Masatoshi INOUE, Takanori MIYAKE, Yuji TANAKA, Katsumi N ...
    1986 Volume 72 Issue 16 Pages 2248-2255
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    In plate rolling, camber is a cause of not only yield loss and poor grade, but also an extra process at the shearing line, calling for an establishment of a camber control technique.
    This report presents the analysis of camber mechanism, the development of camber-meter and the effect of camber control in the Mizushima plate mill. The results obtained are as follows;
    1) Relation between camber and wedge in plate rolling and factors affecting wedge mechanism were clarified, and high-accuracy models applicable to camber control were developed.
    2) Plate camber can be measured accurately regardless of sideslipping or turning of a plate during rolling by a developed camber measuring system (camber meter).
    3) A dynamic camber control technique using camber meter and camber control model was developed. Camber is reduced noticeably in various plate length by applying this control technique.
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  • Shizuo NAKAZAWA, Isao TOMIZUKA, Yutaka KOIZUMI, Hiroshi HARADA, Michio ...
    1986 Volume 72 Issue 16 Pages 2256-2262
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    Effects of some processing factors in Gatorizing process were investigated for a high-W and high-Ta Ni-base superalloy. Optimum extrusion temperature to obtain extrudents suitable for superplastic forging laid near but below 1 200°C, although superplastic deformation was materialized in a temperature range of 1 100 through 1 200°C. Hipping preceding extrusion caused lower superplasticity and narrower temperature range in which superplastically forgiable extrudents were available, while it improved ultimate tensile strength at 760°C and elongation at rupture thereby. Decrease in extrusion ratio caused decrease in pressure required for extrusion, but it casued decrease in superplasticity as well as deteriration of tensile strength at 760°C.
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  • Yoskio HASHIMOTO
    1986 Volume 72 Issue 16 Pages 2263-2270
    Published: December 01, 1986
    Released: June 30, 2009
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    A study has been made of the effects of the conditions of direct hot rolling after continuous casting on the mechanical properties of hot rolled C-Mn-Nb steel sheets.
    The following results are obtained.
    (1) Austenite (γ) grain size after casting is very large compared with that after reheating at 1 250°C for 1 h. Ferrite grain sizes after hot rolling are almost equal in both processes. This is probably because y grain boundaries before hot rolling do not contribute to the ferrite refinement because of their very low densities.
    (2) Tensile test results of steel sheets produced by both processes are almost the same if niobium is almost completely soluted before hot rolling.
    (3). In case, total hot rolling reduction after casting is higher than 40%, total elongation becomes very large.
    (4) Under the experimental condition of total hot-rolling reduction being 88%, the strengthening effect of niobium is saturated when niobium content is more than about.0.035%.
    (5) The effects of the cooling rate in solidification (about 18 and 235°C/min at 1 500-1 300°C) and the heat history difference in the slab width on tensile properties are small in this direct hot rolling simulation test.
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  • Katsukuni HASHIMOTO, Yasuo OTOGURO, Toshiaki SAITO, Hiroyuki KOIKE, Ka ...
    1986 Volume 72 Issue 16 Pages 2271-2278
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    Countermeasures against hydrogen induced disbonding at the interface between 21/4 Cr-1 Mo steel and overlaid stainless steel weldment in reactor vessels which are operated under high hydrogen pressures at elevated temperatures were investigated from the viewpoint of base steel and overlaid stainless steel respectively.
    It is known that the disbonding is caused by formation of carbide after post weld heat treatment and accumulation of hydrogen during cooling at shutdown at the interface. As for base steel, 21/4Cr-lMo steel plate with surface layer 2-3 mm thick of low carbon concentration could prevent the disbonding under ordinary operation condition for direct desulphurizer of heavy oil. The thickness of the low carbon layer could be decreased by decreasing the carbon concentration. It was considered that prevention of the disbonding was realized at carbon concentration less than 0.050.06% at the interface.
    As for overlaid stainless steel, the effect of the amount of δ ferrite on the disbonding was investigation. It was found that more than 18% of δ ferrite after post weld heat treatment was required to prevent the disbonding. δ ferrite seemed to be effective because of decreasing hydrogen content at the interface by increasing mean diffusion rate of hydrogen in the overlaid stainless steel.
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  • Akihiko HOSHINO
    1986 Volume 72 Issue 16 Pages 2279-2286
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    The influence of nitrogen on structure, notched toughness and pitting corrosion resistance of duplex stainless steels was investigated, and a discussion was focussed on the role of N and Mo to pitting corrosion resistance.
    Pitting corrosion test by immersion method showed that the corrosion rate of duplex stainless steels decreased with increasing N content under the presence of Mo. If Mo is absent in the N-bearing steels, beneficial effect of N, which can improve the pitting corrosion resistance of austenite, was not observed.
    Corrosion pits tended to initiate at α/γ interface in the specimens water-quenched, and it was considered that the α/γ interfacial strain was responsible to enhanced corrosion rate of N-free steels.
    The presence of Mo in N-bearing steel was thought not only to suppress the intergranular precipitation of nitride during cooling, but also to retard the pitting growth by lowering the active dissolution rate of anodic ferrite phase.
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  • Takashi SUGMARA, Keizi SAITO, Akihiro GODA, Toshihiko HATA
    1986 Volume 72 Issue 16 Pages 2287-2292
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    A modern analytical computer system has been established as a part of totalized steelmaking information system at the Mizushima works, Kawasaki Steel Corporation. The modernization of the analytical system aimed at automating and refreshing of analytical equipments and real time data processing.
    New computer and electronic technologies and hierarchical structure of computer have realized the system which has centralized the management of information and distributed the control for analytical equipments.
    Furthermore, this system has contributed to improve the reliability through improvement in analytical precision, and also contributed to a decrease in operator's labor, because this system was automated from sample preparation to calculation of analytical contents for powdered samples and pig iron.
    The process control and the quality assurance have been strengthened by the completion of this system.
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  • Kenichi TAKIMOTO, Kenichi SUZUKI, Koichi NISIZAKA, Takashi OHTSUBO
    1986 Volume 72 Issue 16 Pages 2293-2300
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
    A method was established for quantitative analysis of Zn-Fe alloy galvanized layer by using Secondary Ion Mass Spectrometry. O2+, N2+, Ar+and Cs+ were used as the primaries. The sputtering yield and the relative secondary ion yield were found to depend on the alloy composition. The relative secondary ion yield, f(Cx) can be shown as a function of the alloy composition and the ratio of f(Czn) to f(CFe) was independent of the alloy composition. The sputtering yield, the normalized secondary ion intensity, and relative secondary ion yield were also independent of the primary ion current density.
    The secondary ion intensity of Zn and Fe of the Zn-Fe alloy plating by using nitrogen, argon, and cesium as primary ions depended on the coexisting oxygen.
    A linear calibration curve can be obtained between the intensity ratio of IZn/IFe and the ratio of CZn/CFeIt was shown that it is possible to analyse quantitatively the double-layered Zn-Fe alloy plating of micro-sized areas.
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1986 Volume 72 Issue 16 Pages 2305-2307
    Published: December 01, 1986
    Released: February 15, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1986 Volume 72 Issue 16 Pages 2308
    Published: December 01, 1986
    Released: June 30, 2009
    JOURNALS FREE ACCESS
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