Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Search
Advanced search
OR
Browse
Search
Volume 96, Issue 8
Displaying 1-9 of 9 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Fundamentals of High Temperature Processes
Regular Article
  • Viscosity of Iron Oxides Containing Multicomponent Slags
    Sohei Sukenaga, Tetsuya Nagahisa, Yoshiaki Gonda, Noritaka Saito, Junj ...
    Article type: Regular Article
    Subject area: Fundamentals of High Temperature Processes
    2010 Volume 96 Issue 8 Pages 469-474
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.469
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    Viscosity of the multicomponent slags which contain iron oxides (FeO and Fe2O3) have been measured by using rotating crucible method. In our experiments, we measured the viscosity from 1673 to 1873K under air. Effects of the basicity and the iron oxide additions on the viscosity were clarified.
    Temperature dependences of the viscosity for the slags were expressed by Arrhenius type equation in the present study. The viscosity of the slags decreased linearly with increasing the basicity (CaO/SiO2). Also, the viscosity of the slags decreased with increasing the additive content of iron oxides. The decreases in viscosity with the addition of iron oxides are larger in the lower basicity system than those in the higher basicity system. The results of chemical analysis for the slag samples after viscosity measurements indicated that iron oxide in these slags has mainly existed as Fe2O3 (Fe3+). Therefore, we calculated the parameter of αFe2O3 which was a coefficient related to the amphoteric behavior of Fe2O3 in accordance with the Iida's model. The parameter of αFe2O3 increased with decreasing the bacisity. The results suggested that Fe2O3 had a greater tendency to behave as a basic oxide in the lower bacisity system than in the higher basicity system. It is therefore that the decreases in viscosity with addition of the iron oxides are considered to be large in lower basicity system.
    View full abstract
    Download PDF (1111K)
Ironmaking
Regular Article
  • Effect of Carbon Structure Crystallinity on Initial Stage of Iron Carburization
    Ko-ichiro Ohno, Takayuki Maeda, Koki Nishioka, Masakata Shimizu
    Article type: Regular Article
    Subject area: Ironmaking
    2010 Volume 96 Issue 8 Pages 475-481
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.475
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    Iron carburization is one of the most important reactions in iron making process. If the rate and efficiency of carburization reaction are increased, energy consumption of the process will be reduced to a large extent. The purpose of this study is to clarify the effect of carbon structure on initial iron carburization behavior for suggestion of effective carbon utilization in iron making process. Samples of different carbon structures were prepared by heat treatment of CH4 decomposed carbon at various temperatures. Carbon structures of prepared carbon samples were analyzed by a Raman spectroscopy. For experiments, high-purity iron samples directly-contacted with carbon were prepared. A laser microscope combined with an infrared image furnace was used for heating of the sample and “in-situ” observation of carburization phenomena. Carbon concentration profile in iron sample was analyzed by a wavelength dispersion type electron probe micro analyzer. The results of this work showed that primary Fe–C liquid formation temperature became lower from 1439 to 1431K with use of lower crystallization carbon. It was indicated that utilization of the lower crystallization degree of carbon structure causes formation of primary Fe–C liquid at the lower temperature.
    View full abstract
    Download PDF (1508K)
Steelmaking
Technical Report
Casting and Solidification
Regular Article
  • Formation Mechanism of Spheroidal Graphite in Nickel Alloy Cooled Ultra-Rapidly
    Kyoko Wasai, Yousuke Yanagi, Hajime Yamaoka, Nobuya Shinozaki, Hidenor ...
    Article type: Regular Article
    Subject area: Casting and Solidification
    2010 Volume 96 Issue 8 Pages 482-491
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.482
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The formation mechanism of spheroidal graphite (S.G.) in high purity Ni–C and Ni–C–Mg alloys cooled ultra-rapidly from the liquid state at four different rates (Exp. 1–Exp. 4) was investigated. The cooling rate increased from 2×104 to 5×105 (K/s) in the order of the experimental number. Contrary to the previous result on S.G. in Ni–C alloy with impurities, no core of the different phase was found at each center of S.G. (1–3 μm in dia.) in Ni–C alloy in Exp. 1 and a number of the S.G. appeared to have collapsed or burst during the process of growing. In Ni–C–Mg alloy samples of Exp. 1 and Exp. 2, the S.G. with various sizes (1–10 μm in dia.) were observed; some had hallow in each center and some appeared to have collapsed or burst. In Ni–C samples of Exp. 2, Exp. 3 and Exp. 4, and Ni–C–Mg samples of Exp. 3 and Exp. 4, only a few S.G. was found.
    The results could provide two growing mechanisms of the S.G., namely, a heterogeneous nucleation of graphite on a core of the impurity phase formed during cooling, and a nucleation of graphite on the interface between a gas bubble and supercooled liquid nickel. The gas bubble came from vaporized Mg or Ar atmosphere; the Ar gas had been contained in porous alloy sample made of powder of Ni and graphite by pressing. At high cooling rate, the increase or decrease in gas pressure in the bubble would cause the collapse and burst, thus results in a few S.G.
    View full abstract
    Download PDF (4751K)
Chemical and Physical Analysis
Regular Article
  • Investigation of Scale Behaviour during Hot Steel Rolling by Oxide Glass
    Kenichiro Hara, Shoichi Doi, Hiroshi Utsunomiya, Tetsuo Sakai, Shusuke ...
    Article type: Regular Article
    Subject area: Chemical and Physical Analysis
    2010 Volume 96 Issue 8 Pages 492-497
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.492
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    In hot rolling process, scale is formed on steel surface by oxidation at high temperature. As the scale influences the friction between roll and workpiece, the scale affects rolling characteristics significantly. The influence has not been understood sufficiently due to experimental difficulties. The authors proposed to use glass powder to observe the scale as hot rolled. The pickled cold mild steel sheet was inserted to a furnace at hot rolling temperature (1273K) filled with argon. After 600 s, the atmosphere was changed from argon to air to allow oxide scale to grow for 0, 10, 40 s. After the oxidation, the sheet was rolled immediately on a two-high laboratory rolling mill. The thickness was reduced from 10 to 40%. After passing the roll bite, glass powder was sprinkled over the sheet. Scanning electron microscopy on the longitudional section revealed that the scale deformation is relatively uniform if the reduction is lower than 20%. If the reduction is higher than 30%, matrix steel is extruded through cracks in the scale to the outermost surfaces.
    View full abstract
    Download PDF (4351K)
Welding and Joining
Regular Article
  • Microstructure and Bond Strength of Steels Using Low-Cr-Substituted Cementite Foil
    Kouji Tanaka, Hiroyuki Takamiya, Noritoshi Iwata, Koukichi Nakanishi
    Article type: Regular Article
    Subject area: Welding and Joining
    2010 Volume 96 Issue 8 Pages 498-503
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.498
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    In the preceding paper, the eutectic liquid that appears between cementite (θ) foil and austenite has been proposed the most suitable for rapid transient-liquid-phase (TLP) bonding of steels. A partial substitution with Cr was required for metastable θ to be thermodynamically stable up to solidus temperature. On the other hand, the liquid region disappeared quickly by C diffusion and results in a severe Cr segregation at bonded interface. This work aims to decrease the ratio of Cr substitution in θ so as to eliminate a time for homogenization and to allow the use of as-bonded steel parts. The synthesized θ with 1 mass% of Cr (1Cr-θ) showed an enhanced tendency of decomposition on cooling from 1373K. However, the 1Cr-θ filler has been confirmed to give the eutectic liquid that dissolved V during TLP bonding of V-microalloyed steels. After holding for 180 s at 1453K, a gradient ferrite–pearlite microstructure has been attained in the bond without any boundaries or intermediate phases. The bonded steel showed a tensile strength and elongation corresponding to the original V-steel.
    View full abstract
    Download PDF (4752K)
Social and Environmental Engineering
Regular Article
  • Volume of Sedimentary Particles Lifted up by a Swirl Motion of Bubbling Jet
    Toshihide Fujikawa, Masaharu Fukue, Tomomasa Uemura, Manabu Iguchi
    Article type: Regular Article
    Subject area: Social and Environmental Engineering
    2010 Volume 96 Issue 8 Pages 504-510
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.504
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    In our previous research, we mentioned about mixing of small solid sedimentary particles using a swirl motion of a bubbling jet. The lifting behaviors of the particles were classified into two types depending on the aspect ratio (LN/D) of the bath, where LN the nozzle depth and D the bath diameter. The two types of lifting behaviors were closely associated with the isolated vortex appearing for LN/D=0.2–0.4 and twin vortices appearing for LN/D=0.5–0.8. These vortices were similar to the tornado. In this study, empirical equations are proposed for the volume of sedimentary particles lifted up by a swirl motion of a bubbling jet as functions of the gas flow rate, vessel diameter, bath depth, and the physical properties of fluids.
    View full abstract
    Download PDF (1540K)
  • Hydrogen Production by Using Redox Cycle Reaction of Foreign Oxide Coated Iron Oxide
    Shoji Hayashi, Junichi Kinoshita, Hiroaki Kani
    Article type: Regular Article
    Subject area: Social and Environmental Engineering
    2010 Volume 96 Issue 8 Pages 511-516
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.511
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The hydrogen energy society is desirable to mitigate global warming. The redox cycle reaction of iron oxide Fe3O4 which can generate 4.8 mass% hydrogen is considered as one of means to storage and supply it. However, this reaction is known to be significantly retarded due to sintering iron oxide or iron particles. In this work, influence of foreign oxides coating on the surface of iron oxide fines is examined to improve the reaction efficiency.
    Al2O3 coating enhanced the reaction efficiency until 97% even for more redox reaction cycles which is superior to SiO2 coating, probably because of difference of gas diffusivity through coating layers.
    Redox reaction rates in this work were nearly one order of magnitude larger than previous ones, which were obtained with samples prepared by coprecipitation from solution containing additives.
    The activation energy for reduction of Al2O3 coating samples was obtained 41.2 kJ/mol close to that in a literature.
    View full abstract
    Download PDF (1931K)
  • Estimation of Steel Stock in Building and Civil Construction by Satellite Images
    Feng-Chi Hsu, Ichiro Daigo, Yasunari Matsuno, Yoshihiro Adachi
    Article type: Regular Article
    Subject area: Social and Environmental Engineering
    2010 Volume 96 Issue 8 Pages 517-523
    Published: August 01, 2010
    Released on J-STAGE: August 01, 2010
    DOIhttps://doi.org/10.2355/tetsutohagane.96.517
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    Steel is the most widely used material in the world. Many studies related to material flow analysis of steels have been conducted for Japan, Asian countries and the world. Top-down and bottom-up approaches were used in these material flow analyses and stock accounting. However, applicability of these approaches is quite dependent on data availabilities. To overcome this problem, we proposed a methodology to estimate steel stock based on satellite images. Previous studies told us that night time light images collected by satellites have strong correlation with human activities, e.g. electricity consumption, CO2 emissions, GDP, etc., which also links to the amount of steel stock. In this study, night time light image was used along with land cover data to estimate the building and civil construction steel stock in Japan and Asian countries. Analysis was first performed within Japan for each prefecture, and then the result was applied countrywide for Japan, China, South Korea and Taiwan. It was found that the building steel stock showed high relativity with urban night time light while civil construction steel stock was better described by total night time light.
    View full abstract
    Download PDF (5863K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top