Tetsu-to-Hagane

Kinetic Analysis on Gaseous Reduction of Agglomerates, Part 1, Reaction Models for Gaseous Reduction of Agglomerates

Tateo USUI, Masaaki NAITO, Takeaki MURAYAMA, Zen-ichiro MORITA

1994 Volume 80 Issue 6 Pages 431-439
Published: June 01, 1994
Released on J-STAGE: May 07, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_431

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New Smelting Processes and Refractories

Tadaaki TAKAHASHI

1994 Volume 80 Issue 6 Pages 440-445
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_440

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Metallurgy on Galvannealing

Masami ONISHI, Yoshinori WAKAMATSU, Toshitada SHIMOZAKI

1994 Volume 80 Issue 6 Pages 446-450
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_446

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Reduction Equilibria of Ternary Calcium Ferrite with CO-CO₂ Gas Mixture

Takayuki MAEDA, Yoichi ONO

1994 Volume 80 Issue 6 Pages 451-456
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_451

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The reduction behaviors of CaO-Fe₂O₃ binary calcium ferrite and CaO-Fe₂O₃-SiO₂-Al₂O₃ quaternary calcium ferrite are known to be quite different from each other. To clarify the difference, the reduction sequence and reduction equilibrium with CO-CO₂ gas mixture were investigated by using two kinds of synthesized CaO-Fe₂O₃-Al₂O₃ ternary calcium ferrite. One of the samples had an Al₂O₃ content as high as 16 mass% and a composition of CaO·3(Fe_0.74 Al_0.26)₂O₃. The other had a low Al₂O₃ content of 2 mass% and was essentially CaO·Fe₂O₃ containing Al₂O₃ as solid solution.
The results are summarized as follows:
1) The reduction behavior of the ternary calcium ferrite with higher Al₂O₃ content was essentially the same as that of the quaternary calcium ferrite. It was reduced to iron stepwise via magnetite and wustite, both containing Al₂O₃ and CaO as solid solution. In the course of reduction, a calcium aluminate, CaO·Al₂O₃, was precipitated. The equilibrium gas composition vs. temperature curve, of each reduction step was almost the same as the corresponding curve for the quaternary calcium ferrite.
2) The reduction behavior of the ternary calcium ferrite with lower Al₂O₃ content was essentially the same as that of the binary calcium ferrite. But the equilibrium CO contents were considerably higher than those of the binary calcium ferrite.
3) From the results, the difference in reduction behavior between the binary and the quaternary calcium ferrites was attributed to the difference in their crystal structures.

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The Development of the Direct Measurement Technology of the Cohesive Zone and the Structure of the Root of the Cohesive Zone during the Operation of the Large Blast Furnace

Toshikatsu ASHIMURA, Norio MORISHITA, Yoshihiro INOUE, Muneyuki HIGUCH ...

1994 Volume 80 Issue 6 Pages 457-462
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_457

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A belly probe was newly developed at Oita No. 2 blast furnace. It has the function of observing directly the furnace conditions and measuring the solid temperature by an image fiberscope, identifying and measuring layer structure by a microwave during operation, gas temperature and gas composition measurement and taking burden material samples during scheduled shutdown.
The conditions of the lower part of the furnace during operation were observed successfully. Some knowledge relating to the cohesive zone and its surrounding neighborhood were obtained through our measurements.
The results are summarized as follows:
1) The burden materials were observed layer by layer and were found to occasionally be inclined. The maximum inclination angle was estimated to be about 20 degrees.
2) The coke between the cohesive zone and the deadman was observed, as an image, to be floating. The gas volume flowing in this region was estimated to be about at least one third of the bosh gas volume and the gas volume distribution at the lower part of the furnace was estimated to be relatively large.

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Determination of Thermal Diffusivities of Continuous Casting Powders for Steel by Precisely Excluding the Contribution of Radiative Component at High Temperature

Hiromichi OHTA, Minoru MASUDA, Keiji WATANABE, Keiji NAKAJIMA, Hiroyuk ...

1994 Volume 80 Issue 6 Pages 463-468
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_463

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Thermal diffusivity measurements of continuous casting powders for steel have systematically been made at high temperature by applying the differential three layered laser flash method recently proposed by the present authors. The powder consists of SiO₂, Al₂O₃, MgO, CaO, Na₂O and CaF₂. New data processing has also been developed in order to separate the contribution due to radiative component from measured values at high temperature by considering the variation of the absorption coefficients of these powders when adding TiO₂, ZrO₂ or iron oxide. Then, the thermal diffusivity values of continuous casting powders for steel were quantitatively estimated with sufficient reliability. Thermal diffusivity values of continuous casting powders are found to be 4 ± 0.5 × 10^-7m²/s and insignificant with the variation of temperature and concentration presently investigated. It would be interesting to extend the present systematic results for discussing the heat transfer phenomena in the continuous casting process for steel.

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Cutting Force of Low Alloy Steels in the Cutting Speed Range in which a Built-up Edge Forms

Shigeo YAMAMOTO, Hirooki NAKAJIMA, Hirobumi MIYAJI

1994 Volume 80 Issue 6 Pages 469-474
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_469

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A method for estimating the cutting force was studied on the low alloy steels machined with the cutting speed which formed a built-up edge.
At first, the width of the chip shear region(Ws) and the tip radius of the built-up edge(Br) were measured with a micro-machining device. The correlation of them with the hardness of work materials(H) and the cutting speed(V) was obtained.
In the second place, the deformation resistance of the chip shear region (Kfs) and that of the built-up edge(Kfb), which were obtained by the analysis of the previous experimental results, were also correlated with H and V.
Multiple regression analysis was applied between the components of cutting force and the five factors of Br, Ws, Kfs, Kfb and microstructual one. It gave the equations to estimate the cutting forces(principal force, side force and thrust force) from H and V. A good correlation was found between the calculated and the measured values.

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Environmental Effect of Crude Oil Containing Hydrogen Sulfide on Fatigue Properties of Steel Plates for Shipbuilding

Hiroshi OUCHI, Jun'ichi KOBAYASHI, Tadashi ISHIKAWA, Hiroshi TAKEZAWA, ...

1994 Volume 80 Issue 6 Pages 475-480
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_475

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The concentration of diffusible hydrogen introduced into steel, fatigue crack growth rates and fatigue lives were determined in sour crude oil containing a high concentration of hydrogen sulfide and under electrolytic hydrogencharging conditions in neutral solution, using a TMCP high strength steel and a mild steel which are used for ship hull plates. The experimental results demonstrated that the concentration of diffusible hydrogen absorbed into steel was less than 0.1ppm in sour crude oil under atmospheric pressure, and such a small amount of hydrogen accelerated the fatigue crack growth in the high ΔK regime and shortened the fatigue life in the high stress range region, but did not shorten the fatigue life in the low stress region. The electrolytic hydrogen-charging condition appeared to be appropriate as a fatigue-crack-growth test environment to simulate sour crude oil. The deterioration of fatigue characteristics of the TMCP high strength steel was similar to that of the mild steel.

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Influence of Ni and Mn on Toughness of Multi-Pass Weld Heat Affected Zone in Quenched and Tempered High Strength Steels

Toshiei HASEGAWA, Toshiaki HAZE, Shuji AIHARA, Kentaro OKAMOTO

1994 Volume 80 Issue 6 Pages 481-486
Published: June 01, 1994
Released on J-STAGE: May 07, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_481

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Influence of Ni and Mn on toughness of multi-pass weld heat-affected zone (HAZ) in quenched and tempered high strength steels was investigated in order to make clear the metallurgical factors controlling the toughness of the local brittle zone (LBZ) in the HAZ.
Change of simulated HAZ microstructure due to chemical compositions and thermal cycle condition is expressed by a modified hardenability index (S_I), which corresponds to ideal critical diameter (D_I) taking account of the factors of boron and austenite grain size for the HAZ. Simulated HAZ toughness has good correlation with S_I and Ni content. The highest toughness is obtained at optimum S_I value (≅ 11) regardless of the chemical compositions and the thermal cycle conditions.
For lower bainite, martensite and their mixtures, cementite which precipitated in the laths of auto-tempered martensite during cooling has a important role for controlling the toughness. But, fracture facet size or retained austenite is not a main controlling factor.

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Calculation of Constitution of Nickel Base Superalloys by Cluster Variation Method

Masato ENOMOTO, Hiroshi HARADA, Hideyuki MURAKAMI

1994 Volume 80 Issue 6 Pages 487-492
Published: June 01, 1994
Released on J-STAGE: January 18, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_487

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High temperature performance of nickel-base superalloys vitally depends on the constitution of alloys, i.e. volume fraction and composition etc. of constituent phases. The development of computer models to predict the effects of multiple alloying additions on the alloy constitution may facilitate the designing of alloys and lead to further improvement of high temperature performance. Some of the present authors have demonstrated that the cluster variation method with tetrahedron approximation which utilizes the Lennard-Jones pair potential can predict satisfactorily various characteristics of γ'/γ equilibrium in Ni-Al alloys containing one or two alloying elements without excessively increasing the computational load. In this study, calculations are extended to some practical and experimental multicomponent alloys and the results are compared with experimental data on the volume fraction and composition of γ' and γ phases, lattice misfit and site occupation of alloying elements in the γ' lattice. In the present form the model can be used to calculate the constitution of single crystal superalloys in which no interstitial trace elements such as carbon and boron are added to prevent grain boundary embrittlement.

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Introduction to Solidification of Metals (III)

Koki GUNJI

1994 Volume 80 Issue 6 Pages N266-N280
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_N266

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MF Process for EAF Dust Treatment

Yasuyuki MURAYAMA

1994 Volume 80 Issue 6 Pages N281-N284
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_N281

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Plasma Spraying for Production Process of Advanced Energy Devices

Akira NOTOMI

1994 Volume 80 Issue 6 Pages N285-N289
Published: June 01, 1994
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.80.6_N285

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