Tetsu-to-Hagane

Growth Kinetics and Alloying Element Partition of Proeutectoid Ferrite

Toshimi TARUI, Masato ENOMOTO

1988 Volume 74 Issue 4 Pages 591-600
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_591

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Hydrogen-Defect Interactions and Hydrogen-Induced Embrittlement in Iron and Steel (1)

Makio IINO

1988 Volume 74 Issue 4 Pages 601-608
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_601

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Computer Control of Mechanical Properties for Manufacture of Steel Plate-Present State and Future Problem

Yoshiyuki SAITO

1988 Volume 74 Issue 4 Pages 609-616
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_609

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Manufacturing Techniques for Rolled Clad Products

Takao KAWANAMI, Seishiro YOSHIWARA

1988 Volume 74 Issue 4 Pages 617-623
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_617

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Disintegration of Coke by Mechanical Impact under Gasification Reaction

Yuji IWANAGA, Kouji TAKATANI

1988 Volume 74 Issue 4 Pages 624-631
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_624

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In order to clarify the behavior of fines in blast furnace, fundamental experiments were performed on the disintegration of coke during gasification reaction accompanied by mechanical impact.
The following results were obtained :
(1) Coke fines of high ash content are generated with the progress of gasification, which suggests the close correlation between generation of coke fines and gasification.
(2) Generation of coke fines increases remarkably when the mechanical impact strength is beyond a critical value.
(3) Reaction temperature, gas composition and coke size also affect the generation of coke fines by varying the rate of gasification.
A mathematical model is made using the rate equation of coke fine generation deduced from the experimental results. The calculated results agree well with the experimental results. The model, therefore, can be applied for the investigation of the bahavior of coke fines in blast furnace.

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The Solubility of the Chromite in MgO-Al₂O₃-SiO₂-CaO Melts at 1 600°C in Air

Kazuki MORITA, Tomoki SHIBUYA, Nobuo SANO

1988 Volume 74 Issue 4 Pages 632-639
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_632

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The solubility of the picrochromite MgO·Cr₂O₃ into MgO-Al₂O₃-SiO₂ melts were measured at 1 600°C in air, to understand the bahavior of smelting reduction of chromite ore. The solubility of picrochromite were 1.1-4.5wt% Cr₂O₃ in MgO-SiO₂-Cr₂O₃ melts. In MgO-CaO melts, they were as much as 40-55wt% CrO_x, although more than 50% of chromium exists as Cr⁶⁺ in the high CaO and low MgO region. The solubility of the picrochromite increased from 0.2-0.8wt% Cr₂O₃ to 0.5-2.6wt% Cr₂O₃ by adding CaO to the MgO-Al₂O₃-SiO₂ melts. For Al₂O₃ containing melts, the chromium in the chromite MgO·Cr₂O₃ was substituted by aluminum in proportion to Al₂O₃ content in the melt.

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Copper Distribution between Na₂S Bearing Fluxes and Carbon Saturated Iron Melts

Tadashi IMAI, Nobuo SANO

1988 Volume 74 Issue 4 Pages 640-647
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_640

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Copper distribution between NaS_0.5 bearing fluxes and carbon saturated iron melts was measured at 1 200°C. Coefficients L_Cu and K_Cu which are defined below were used to discuss the decopperization behavior of different sulfide fluxes with different sulfur content in carbon saturated iron melts. L_Cu≡(%Cu)/[%Cu] K_Cu≡(%CuS_0.5)/[%Cu]·[%S]^1/2
The results are summarized as follows.
1) The distribution ratio L_Cu was between 11 and 21.5 for the NaS_0.5-FeS-CuS_0.5 system at 1 200°C. The maximum K_Cu was 213 for the 95%NaS_0.5-5%FeS system with L_Cu=17 and [%S]=0.01.
2) The temperature dependence of K_Cu, from 1 170°C to 1 325°C for the melts containing 79.9-88.5%NaS_0.5+10.7-19.4%FeS+0.55-0.76%CuS_0.5 can be expressed by the following equation.
lnK_Cu=1.25×10⁴/T-3.07
3) NaS_0.5 was found to be the best component for the decopperization among five sulfides FeS, NaS_0.5, KS_0.5, CaS, CuS_0.5 investigated in the present work.

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Wettability of Solid Oxides by Liquid Iron Alloys under Reduced Pressure

Kiyoshi NOGI, Kazumi OGINO, Tetsuma KURACHI

1988 Volume 74 Issue 4 Pages 648-655
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_648

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Wettability of solid oxides by liquid iron alloys has been studied under reduced pressure. Measurements of surface tension and contact angle of liquid iron alloys on solid oxides (MgO, Al₂O₃) have been carried out with the sessile drop method.
1) Different values of surface tension and contact angle were obtained by different furnaces whose heating elements were molybdenum and graphite, respectively. This can be explained by a difference in partial pressure of oxygen in the furnaces.
2) The values of surface tension obtained by the furnace whose heating element was graphite was considerably higher than previous works. It should be caused by an extremely low oxygen pressure in this work compared with those in previous works.
3) The difference in the wetting of Al₂O₃ and MgO with liquid iron alloys can be attributed to the difference in solubilities of Al and Mg in liquid iron.

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Activities of Components in Iron oxysulphide Melt in Equilibrium with Solid Iron

Shoji HAYASHI, Yoshiaki IGUCHI

1988 Volume 74 Issue 4 Pages 656-663
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_656

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Equilibrium between H₂-H₂O-H₂S mixtures and iron oxysulphide melts in coexistence of solid iron was accomplished by means of the gas circulating method. The temperature range of measurements was 1 000 to 1 200°C, and the mole fractions of oxygen and sulphur in the melt were N_o =00.35 and N_s= 0.180.43, respectively. The oxygen pressure in gas was measured by oxygen galvanic cell using calcia-stabilized zirconia as a solid electrolyte. The sulphur pressure in gas was determined by chemical analysis.
The activities of oxygen and sulphur in the melt showed slightly positive deviation from the fractional concentration of each anion i, N'_i =N_i/(N_o+N_s) modified by a solution model.
The partial molar quantities of species in the solution at 1 100°C were calculated from results of the activities. It was shown that oxygen exothermically dissolves into the solution and has a small inclination of imperfect mixing at N'_o=0.2, whereas sulphur plays nearly an ideal behavior in the solution.
The sulphur potential in equilibrium with iron, wustite and the melt was in close agreement with those in earlier works.

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Development of Automatic Blowing Technique in BOF Based on a Mathematical Model

Takeshi TAKAWA, Mitsunobu SATO, Takashi OKADA, Masahiko INUI, Takashi ...

1988 Volume 74 Issue 4 Pages 664-671
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_664

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For the endpoint control and the estimation of steel compositions at the end point in BOF with top and bottom blowing, a mathematical model suitable for online application has been developed on the following procedure.
(1) The basic equations of oxygen consumption ratio and temperature increase ratio have been developed. These equations have comprehensive characteristics in both low and high carbon ranges at the final stage of blowing.
(2) An endpoint control model for coinciding the carbon content and temperature at the end point with their aimed values has been developed on the basis of the above mentioned basic equations.
(3) Equations for the estimation of manganese and phosphorus contents at the end point have been developed by using the values obtained by analysis of the steel sampled by sub-lance measurement during blowing and the amount of oxygen which was not consumed for decarburization during the period from sublance measurement to the end point.
At No. 2 BOF shop in Wakayama Steel Works, the models are being used for the automatic blowing and contributes to the reduction of reblow ratio and the improvement of quick tapping ratio.

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Quantitative Estimation about the Influence of Various Factors on the Smelting Reduction Rate of Cr-ore by Top-and-bottom Blowing Converter

Shin-ya KITAMURA, Takashi ARAI, Michitaka MATSUO, Nobuo SATO, Kazuo OK ...

1988 Volume 74 Issue 4 Pages 672-679
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_672

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Smelting reduction rate of Cr-ore in top-and-bottom blowing converter was quantitatively estimated by 600 kg scale fundamental experiment and 100 t scale industrial furnace (LD-OB). The change of Cr oxide in slag with time showed zero-order reaction kinetics and the following points were clarified on the reduction rate.
1) The rate was in propotion to ε^0.5 and L^1.0, where ε was stirring energy, L was diameter of furnace.
2) The activation energy was about 210 kJ/mol.
3) The rate were not cleary affected by the kind of Cr-sources, namely, pellets, briquettes of powder ore, carbon containing briquettes and lump ore.
4) The rate increased with the increase in amount of carbon for reduction and the decrease of [%Cr].
According to these results, it was posturated that the transfer of Cr oxide in molten slag phase to the carbon-slag and the metal-slag interfaces was the rate controlling step. The reduction rate was formulated as a function of ε., L, [%Cr], temperature and the containing ratio of carbon for reduction in slag. The results of calculation showed fairly good agreement with the observed values.

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Smelting Reduction of Chrome Ore Pellet in Stirred Bath

Masaki FUJITA, Hiroyuki KATAYAMA, Masatoshi KUWABARA, Chikara SAITOU, ...

1988 Volume 74 Issue 4 Pages 680-687
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_680

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Stress Analysis of Grooved Rolls Having Closed Passes and Discussion on Their Groove Shapes by photoelastic Methods

Kenji MIYAZAWA

1988 Volume 74 Issue 4 Pages 688-695
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_688

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There was a breaking accident of a solid grooved roll having closed passes, which seemed to be broken at a groove bottom mainly by mechanical stresses.
The stresses were analyzed by a three-dimensional photoelastic method and the cause of the breakage was studied. The effect of groove shapes on the stress distribution of the grooved roll was investigated by a two-dimensional photoelastic method. The main results obtained are as follows :
1) As a result of the stress analysis of the solid grooved roll having closed passes, it became clear that the breakage was caused by too large mechanical working stresses.
2) To prevent the breaking accident of the grooved roll at a groove fillet, it is most effective to make the diameter of the groove and collar as large as possible.

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Development of a Simulation Testing Machine for Evaluating the Lubricity of Lubricant in Cold Sheet Rolling

Akira AZUSHIMA

1988 Volume 74 Issue 4 Pages 696-702
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_696

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The new simple simulating tests have always been desired strongly in order to evaluate the lubricity of lubricant in cold sheet rolling, because of complexity and cost of experimentation with actual rolling processes. The purpose of the study is to develop a new simulation testing machine. In the new type of simulating test, it is necessary to deform, the workpiece material plastically which is different from the simulating test such as Timken test. The contact behavior between rolls and workpiece is undoubtedly closer to that in rolling practice. The roll can be rotated at a high relative speed and moreover, the normal force and tangential force can be measured individually. The new simulation testing machine developed is sufficient for these necessary conditions. The apparatus is very simple and the cost for experiments is cheap. This machine is effective for evaluation of the lubricity of lubricant in cold sheet rolling.

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Transvers and Longitudinal Yield Strength of Hot-rolled Seamless Linepipe

Akira YAGI, Takaharu SHIMIZU, Yasuo SOGO, Katuharu NAKAMURA

1988 Volume 74 Issue 4 Pages 703-709
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_703

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The transverse yield strengths of hot-rolled seamless linepipes were studied with respect to the different test methods, including the tensile tests with cold-flattened strap and unflattened round specimens. These results were compared with the longitudinal yield strength and the yield strength obtained by the ring ex pansion test, and were discussed in relation to yielding of a pipe under triaxial stress state. The following conclusions are reached from the experimental results and discussion.
(1) There is little difference between the longitudinal and transverse tensile properties of hot-rolled seamless linepipe.
(2) The cold-flattened strap specimen does not represent the true material properties, because of the pipe-size effect on the yield strength.
(3) The transverse yield strength, which is obtained with the cold-flattened strap specimen, can be well explained with the combination of work-hardening and the Bauschinger effect.
(4) As for the hot-rolled seamless linepipe, the use of longitudinal tensile specimens should be recommended as the most reliable practical method for the purpose of quality control.

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Fabrication of Silicon-Carbide Continuous Fiber Reinforced Carbon (SiC/C) Composites Using Hot Press Process and the Effects of Fiber Forms on the Strength

Tong Shik CHANG, Akimitsu OKURA

1988 Volume 74 Issue 4 Pages 710-717
Published: April 01, 1988
Released on J-STAGE: January 15, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_710

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Silicon-carbide continuous fiber reinforced carbon (SiC/C) composites was fabricated using a simple hot press process. Three forms of SiC fiber reinforcement, that is, cloth, mat and unidirectional long fibers (UD fibers) were employed. Fine pulverized coke mixed with carbonaceous bulk mesophase (BM) was used as matrix. In this process, SiC fibers were laminated alternately with the matrix admixture in a die, and then heated to 600°C under a pressure of 49 MPa.
The results were as follows:
(1) The maximum strengths of the composites were the greatest for the UD fiber reinforcements at 121.5 MPa while the cloth and mat reinforcements showed appreciably lower strengths.
(2) After secondary heat treatments at 800°C to 1 500°C, the composite reinforced with UD fibers showed excellent strengths above 106 MPa which were greater than that of an as-fabricated commercial C/C composite. The strengths of the composites reinforced with cloth and mat, however, were significantly reduced by the heat treatments.

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Visual Observations of Fatigue Crack Propagation of a Low Alloy Steel in High Temperature Pressurized Water

Norio NAGATA, Yasuyuki KATADA

1988 Volume 74 Issue 4 Pages 718-724
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_718

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Visual observations of fatigue crack propagation of a low alloy steel in an autoclave filled with pressurized water at high temperatures simulating a boiling water reactor environment were conducted. The observation system consisted of a distant focusing relay lens, a camera and a picture control device. A sapphire single crystal rod was employed as solid light path in high temperature water in order to reduce the image distortion due to convection. Observations were carried out at temperatures ranging from room temperature to 288°C. The total resolution power of the observation system decreased with increasing temperature but satisfied a requirement of ASTM standard even at temperature of 288°C.
Crack growth curves were successfully obtained from the successive pictures and compared with those obtained by a compliance method using LVDT for the same specimen. A good coincidence was obtained between both measurements.

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Fretting Fatigue of High Strength Steels for Chain Cables in Sea Water

Kozo NAKAZAWA, Masae SUMITA, Norio MARUYAMA, Yoshikuni KAWABE

1988 Volume 74 Issue 4 Pages 725-732
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_725

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Fretting fatigue tests of high strength steels having ultimate tensile strengths of 490, 690 and 880 MPa were carried out in sea water under free corrosion condition, and the effect of fretting damage on fatigue life was investigated. At high stress amplitude, the higher the strength of steel, the longer the fretting fatigue life. At low stress amplitude, the fretting fatigue life of all the steels decreased to 10-20% of the conventional corrosion fatigue life and showed almost the same life irrespective of the strength of steel. The fretting fatigue life in sea water was much shorter than that in air, and the fretting fatigue strength at 10⁷ cycles was lower in sea water than in air. The saturation of fretting fatigue damage occurred beyond a certain number of fretting cycles. The ratio of the smallest number of fretting cycles to the fretting fatigue life for the saturation to occur in sea water was less than 0.005%, but that in air was about 30%. It was shown that the fatigue life in sea water was lowered by the fretting damage of a small number of fretting cycles.

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Phase Diagram of Fe Rich Side of Fe-Mo System under High Pressure

Yoritoshi MINAMINO, Toshimi YAMANE, Hideki ARAKI, Akitoshi HIRAKI, Yos ...

1988 Volume 74 Issue 4 Pages 733-740
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_733

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High-pressure phase diagrams of the iron-rich Fe-Mo system were determined by a diffusion-couple method and the results were compared with the calculated phase diagrams. Under high pressure the α-phase region became narrower, while the γ-region wider. When the pressure was about 3.2 GPa, the γ-loop was no more present and instead the contracted γ-field appeared in the Fe-Mo system.

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Measurements of Hydrogen Content at Inside Wall of Crack in Stress Corrosion Cracking

Koji YAMAKAWA, Harushige TSUBAKINO, Hideyuki MITSUMATA, Kwang Bae KIM

1988 Volume 74 Issue 4 Pages 741-743
Published: April 01, 1988
Released on J-STAGE: January 15, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_741

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[title in Japanese]

[in Japanese]

1988 Volume 74 Issue 4 Pages 747-748
Published: April 01, 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_747

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Erratum to : Recent Titanium Melting Techniques and the Effective Way to Improve Titanium Ingot Quality

1988 Volume 74 Issue 4 Pages N142
Published: 1988
Released on J-STAGE: May 29, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.74.4_N142

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