Tetsu-to-Hagane

Establishment of Mass-production Technology and Supply System on High-grade Lime and Dolomite

Hyoza YOSHIZAWA

1987 Volume 73 Issue 10 Pages 1273-1280
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1273

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U. HUGUENIN "Het Gietwezen in's Rijks Ijzer-Geschutgieterij to Luik" and a Significance in the History of Japanese Iron Making Industory

Masao SERIZAWA

1987 Volume 73 Issue 10 Pages 1281-1287
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1281

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Available Rare Elements for Advanced Science and Technology

Hideyuki YOSHIMOTO

1987 Volume 73 Issue 10 Pages 1288-1296
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1288

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Lubrication System in Ultra-high Vacuum

Nobuo OHMAE

1987 Volume 73 Issue 10 Pages 1297-1302
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1297

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Role of Vacuum in High-technologies

Katsuya NAKAYAMA

1987 Volume 73 Issue 10 Pages 1303-1308
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1303

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Arc Discharge and Its Application

Masao USHIO

1987 Volume 73 Issue 10 Pages 1309-1315
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1309

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Non-destructive Testing Personnel Education, Training and Qualification System in Iron and Steel Industries

Keiji IBA

1987 Volume 73 Issue 10 Pages 1316-1322
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1316

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Method of Determination of Parameters Included in ISHIDA-WEN'S Model

Takeaki MURAYAMA, Yoichi ONO

1987 Volume 73 Issue 10 Pages 1323-1328
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1323

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A method of determination of the rate parameters (chemical reaction rate constant, effective diffusivity in the product layer and effective diffusivity in the reaction zone) and Thiele's modulus included in ISHIDA-WEN's model is proposed. With this method, those parameters can be determined easily from reduction data. This method was examined by being applied to the reduction curve calculated by ISHIDA-WEN's model and the experimental data of gaseous reduction of iron oxide pellets. This method was useful especially in the case of smaller value of Thiele's modulus.

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Effect of the Addition of SiO₂ and CaO on the Reduction of Dense Wustite with H₂

Nobukazu SHIGEMATSU, Hikoya IWAI

1987 Volume 73 Issue 10 Pages 1329-1336
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1329

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The dense wustite plates containing SiO₂ and CaO were reduced isothermally in H₂ gas stream over a temperature range of 670 to 930°C. The wustite samples used in this work consist of FeO phase dissolving SiO₂ and CaO, Fe-Ca olivine and dicalcium silicate. It was clear that the reduction rate of the samples was affected mainly by the additives dissolved in FeO phase and slightly by the complex oxides. By the presence of very small amount of SiO₂ dissolved in FeO phase the reduction was promoted at temperatures above 800°C and retarded at temperatures below 730°C. The reduction was promoted very much by the presence of dissolved CaO over a temperature range of this work. It was recognized that the effect of these dissolved oxides on the reduction rate originated from their effect on the morphology of the reduced iron.

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Mass Spectrometric Determination of Interaction Parameters for P₂O₅ with CaO, MgO, MnO and SiO₂ in Fe_tO-P₂O₅ System

Nobuaki OHARA, Shinya NUNOUE, Eiichi KATO

1987 Volume 73 Issue 10 Pages 1337-1342
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1337

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The effects of CaO, MgO, MnO and SiO₂ on the activity coefficient of P₂O₅ in dilute solution of P₂O₅ in Fe_tO were determined at 1370°C by the use of a mass spectrometer-Knudsen cell combination. The activity of P₂O₅ was determined by the use of the following chemical equilibrium. Iron vapor in equilibrium with solid iron was used as internal standard.
PO ( g )+ P₂O₅( in slag ) = 3PO₂(g)
a_P₂O₅ = K·^P³_PO₂_{P_PO}=K'·^{(I⁺_PO₂/I⁺_Fe)³}_{(I⁺_PO/I⁺_Fe)}
The interaction parameters have been calculated from the activity coefficient of P₂O₅ with the aid of the least square method. The obtained results are as follows.
ε^CaO_P₂O₅ = - 23 ± 3 ε^MgO_P₂O₅ = - 20 ± 2
ε^MnO_P₂O₅ = - 13 ± 1 ε^SiO₂_P₂O₅ = - 4 ± 1
These interaction parameters are for dilute solution of P₂O₅ in Fe_tO.

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Kinetic Studies on the Rate of Reaction between Molten Slag and Metal with Gas-injection Stirring

Masahiro HIRASAWA, Kazumi MORI, Masamichi SANO, Asao HATANAKA, Yuhji S ...

1987 Volume 73 Issue 10 Pages 1343-1349
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1343

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Kinetic studies have been made on the rate of reaction between molten slag and metal with gas-injection stirring. The explored reaction is oxidation of Si in molten Cu by FeO in a Li₂O-SiO₂-Al₂O₃-FeO slag taking place under the condition of rate-controlling by Si transport in the metal phase. Kinetic experiments were done at 1250°C. The slag-metal bath was stirred by Ar gas injected through a nozzle located at the crucible bottom. The apparent metal-side mass-transfer coefficients of Si, k_Si', are calculated from the kinetic data. Relations between k_Si' and experimental conditions (gas flow-rate, V_g ; metal depth, h_M; slag depth, h_sl ; crucible diameter, d_c) have been investigated.
k_Si' is found to increase generally with increasing V_g. The dependence of k_Si' on the gas flow-rate varies at certain gas flow-rates denoted by V_g^* and V_g^**.In the low V_g range (V_g<V_g^* : Region I), k_Si' is proportional to ( V_g/d_c²)^1/2. In the medium V_g range (V_g^* <V_g<V_g^** : Region II), the effect of the increase in gas flow-rate on k_Si' is cosiderably smaller than in Region I. In the high V_g range (V_g>V_g^**: Region III), the extent of the increase in k_Si' with V_g increases again. It is also found that k_Si' increases with metal depth, h_M, below a transitional depth, h_M^*. Above the transitional metal depth h_M^*, k_Si' becomes independent of h_M. Examinations have been performed of the influence of slag depth, h_sl, on k_Si' in Regions I and II. In Region I, k_Si' is independent of h_sl. In Region II, k_Si' decreases with the decrease of slag depth.

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The Analysis of Metal-side Mass-transfer in a Slag-Metal Reaction System with Gas-injection Stirring

Masahiro HRASAWA, Kazumi MORI, Masamichi SANO, Yuhji SHIMATANI, Yoshim ...

1987 Volume 73 Issue 10 Pages 1350-1357
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1350

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A theoretical analysis has been made on the metal-side mass-transfer in a slag-metal reaction system with gas-injection stirring. Considerations have been given of the fluid flow in the vicinity of the slagmetal interface. On the basis of a theory of turbulence phenomena, metal-side mass-transfer coefficients are derived as functions of gas-injection stirring conditions. The theoretical equations are rearranged to dimensionless correlation equations.
The mass-transfer data obtained by the authors for molten slag-Cu reaction system of Si oxidation by FeO at 1250°C and the available data of model studies at low temperature (aqueous solution-amalgam system at room temperature and molten salt-molten Pb system at 450°C) are correlated successfully by the equations obtained in the present study. It is found that the dimensionless correlation equations obtained in the present study are applicable to the data of ladle desulfurization, as far as the rate is controlled by the mass-transfer in the metal phase.

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Development of Forward Slip Ratio Control in Tandem Cold Rolling

Hiroyasu YAMAMOTO, Jun HASHIMOTO, Teruhide NIDOME, Toshiyuki SHIRAISHI ...

1987 Volume 73 Issue 10 Pages 1358-1365
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1358

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In order to achieve the high productivity in a continuous tandem cold mill, the control system of forward slip ratio has been developed by the use of a supply device of rolling lubricant, which works in quick response to the lubricant flow and concentration.
In the calculation model of this control system, the method which modifies BLAND & FORD'S equation with a slide factor for calculation of friction coefficients is used to estimate negative values of forward slip ratio in addition to positive values. As for the supply device of rolling lubricant, emulsion stability and particle size distribution of lubricant obtained by a static mixer are equivalent to those by a convenient device. A high-speed and stable rolling without chattering can be realized by controlling the supply amount of rolling lubricant in the present control system of forward slip ratio.

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Development of Computer Control Techniques for Tandem Mill with Grooved Rolls

Takashi FUJIMOTO, Kazushi BABA, Kazuo ARAI, Teruyuki NAKANISHI, Junjir ...

1987 Volume 73 Issue 10 Pages 1366-1372
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1366

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Kawasaki Steel has recently developed computer control techniques for a 4-tandem mill with grooved rolls at the billet mill in Mizushima Works.
These techniques consist of set-up and dynamic control functions. The purpose of set-up control is to decide the manipulating variables (roll gap, roll revolution) which cause material dimensions to achieve the aimed value by means of the mathematical models. We have developed such presice models as to be applied to on-line control. On the other hand, the purpose of dynamic control is to achieve uniform sectional dimensions along the length of the material. Development has also been made on the new sectional profile control technique to utilize dynamic roll gap control, firstly as a grooved mill.
As the result of these application, the dimensional accuracy of the product has been significantly improved in the mill.

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Morphological Control of Carbo-nitrides and Hot Ductility in Low Carbon Low Alloy Steels

Yasuhiro MAEHARA, Kunio YASUMOTO, Hiroshi TOMONO, Yasuya OHMORI

1987 Volume 73 Issue 10 Pages 1373-1380
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1373

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Effect of thermo-mechanical history during cooling from solution treatment temperature of 1 300°C on the ductility at 800°C at a strain rate of 10^-3 s^-1 of low carbon low alloy steels has been investigated by means of hot tensile test in relation to surface cracking of continuously cast (CC) slabs. The ductility evaluated by reduction in area of the specimens directly cooled to the deformation temperature is largely reduced by the slow strain rate deformation especially in Nb steels, since ductile intergranular fracture of austenite easily occurs because of the dynamic precipitation of NbC and/or AlN within the matrix as well as on the grain boundaries. By decreasing the cooling rate or by isothermal holding at around 1 100°C, the ductility is significantly improved and the fracture mode changes into transgranular ductile, because the dynamic precipitation is much reduced by the depletion of preciptating elements due to nucleation and coarsening of the precipitates in these processes. This however takes extremely long time to achieve the coarsening of the precipitates in conventional CC process and is not practical. In order to accelerate this phenomenon the effect of the prior deformation was examined and the optimum conditions suitable for CC process were determined. In the case of continuous cooling the predeformation larger than 5% should be applied at temperatures around 1 050°C at strain rates larger than 10^-2 s^-1. The ductility of the specimens predeformed at lower temperatures can also be improved by employing the subsequent reheating process.

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Effect of Thermo-mechanical History on Surface Cracking of As-cast Low Carbon Low Alloy Steel Slabs

Kunio YASUMOTO, Yasuhiro MAEHARA, Tsuneaki NAGAMICHI, Hiroshi TOMONO

1987 Volume 73 Issue 10 Pages 1381-1388
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1381

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Surface cracking and the effect of predeformation on the cracking of continuously cast (CC) low carbon low alloy steel slabs have been studied by means of hot bending tests simulating a practical CC and the direct rolling process using the as-cast thin slabs. Two kinds of cracking, i. e., fine transverse cracks in microalloyed steels due to carbonitride precipitation during slow strain rate deformation of 10^-3 s^-1 and severe cracks in low carbon Al-killed steels due to sulfide precipitation during high strain rate deformation of 10 ^-1 s ^-1were easily simulated by the deformation in low temperature γ region. The both kinds of cracking were markedly suppressed by the slight predeformation on the slab surface during cooling to the deformation temperature. Since γ grain size was not changed by the predeformation, these results can be explained in terms of precipitation behavior of carbonitride or sulfide in each case. That is, the precipitates formed by the predeformation can grow into coarse particles during the cooling stage, resulting in marked suppression of fine precipitation which causes large ductility loss in the subsequent bending process.

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Production of Tungsten Wire Reinforced Cobalt Base Superalloys by Vacuum Casting and Their Creep Rupture Properties

Takashi ARAI, Toshiharu KOBAYASHI, Takehiko ITAGAKI, Kisaburo KOIKE, N ...

1987 Volume 73 Issue 10 Pages 1389-1396
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1389

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For improving endurance temperature of superalloys, an investigation was carried out into mould conditions of vacuum casting procedure and into fabrication conditions of tungsten fibre reinforced cobalt-base superalloys.
Creep testing was performed for the test-pieces, which were prepared by the method found to be the optimum in the above experiment. The tungsten wire was 1 mm in diameter and the matrix alloy was X-45 or its modification with respect to tungsten content. The fibre content was 50%. The strength of the composites was considerably lower than that expected from the combination of the wire and the matrix when the tungsten content in the matrix was low. This was due to the partial dissolution of the wire into the molten alloy during casting.
The effect of the thermal degradation of the wire during fabrication on the strength of the composite decreased with the increase in testing period, because the rate of decrease in the wire strength was smaller for the wire which had once experienced a high temperature as compared with the wire which had not. Although nickel-induced recrystallization was not observed, growth of reaction zones as well as formation and growth of voids proceeded during creep testing. Their effect on the strength of the composite was possible.

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Effect of Microstructural Factor on Impact Toughness of Ti-6Al-2Sn-4Zr-6Mo Alloy

Mitsuo NIINOMI, Ikuhiro INAGAKI, Toshiro KOBAYASHI

1987 Volume 73 Issue 10 Pages 1397-1404
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1397

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The instrumented Charpy impact test and dynamic fracture toughness test are carried out on variously heat treated Ti-6Al-2Sn-4Zr-6Mo alloy, and the effect of microstructure on toughness under impact loading is examined.
In equiaxed α structural specimens, Charpy absorbed energy (E_t) value increases with the increase of solution treatment temperature below 1 123 K, and then decreases with increase of solution treatment temperature above 1 123 K. E_t value is strongly influenced by the cooling rate after solution treatment. In equiaxed α structural specimens, the tendency of the change in dynamic fracture toughness (J_d) with solution treatment temperature is similar to that of E_t value. However, the degree of the change in J_d value and the effect of cooling rate after solution treatment on J_d value are significantly small. E_t and J_d values are remarkably large in acicular structural specimens which are furnace cooled after solution treatment in the β region. In acicular α structural specimens, E_t and J_d values increase with the increase of prior β grain size. However, in equiaxed α structural specimens, E_t value rather decreases with increase of prior β grain size although J_d value increases. E_t and J_d values increase with the increase of the roughness of fracture surface.

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Impact Toughness of Hydrogen Charged Ti-6Al-2Sn-4Zr-6Mo Alloy

Mitsuo NIINOMI, Kenzi SUZUKI, Toshiro KOBAYASHI

1987 Volume 73 Issue 10 Pages 1405-1412
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1405

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The effect of various heat treatments on the behavior of the hydrogen embrittlement of Ti-6Al-2Sn-4Zr-6Mo alloy, and the relation between hydrogen embrittlement and microstructural factor was investigated.
In the case of the specimens which were air cooled after solution treatment in the (α+β) region, the width of hydrogen embrittled fracture surface, which corresponded to the hydride formation zone, and the hydrogen embrittlement ratio increased with the increase of solution treatment temperature, namely the decrease of the areal percentage of primary α. On the other hand, in the case of the specimens which were water quenched after solution treatment in the (α+β) region, the opposite tendency was observed. In the case of solution treatment temperature higher than 1 173 K, the width of hydrogen embrittled fracture surface and the hydrogen embrittlement ratio increased in the order of furnace cooled, water quenched and air cooled specimens after a solution treatment with the same treatment temperature. The hydrogen embrittlement ratio was lower and the width of hydrogen embrittled fracture surface was wider in the specimens which were solution treated in the β region than that in those which were solution treated in the (α+β) region with the same cooling condition after solution treatment.

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Determination of Impurities in Titanium and Titanium Alloy by ICP Atomic Emission Spectrometry

Michihiko FUJINE, Masanao NARITA, Fumikichi MOGI

1987 Volume 73 Issue 10 Pages 1413-1418
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1413

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The application of ICP-AES method was investigated for the rapid analysis of impurities in titanium and it's alloy. Elements for analysis were Mn, Cu, Ni, Cr, Mo, Sn, Zr, Fe, Y, Al and V. Good results were obtained by using titanium as an internal standard, which were enough preferable to the precision and the accuracy in the comparison with chemical analysis.
After the acid decomposition of metal sample (0.5 g) and fuming of H₂SO₄, the solution is diluted to 100 ml with water for the ICP determination.
The detection limits in the present method are 0.0001% for Mn and Y, 0.001% for Cu, Ni, Cr, Mo, Zr, Fe and Al, and 0.01% for Sn and V, which mostly show better results than those of widely used analysis. In the determination of Ti-6Al-4V alloy, however, corrections are needed according to the contents of V and Al.

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An Experimental Investigation on Formation of Electrical Discharge Hardening Layer on Emission Spectrometric Analysis of Steels

Takashi SUGIHARA, Keizi SAITO, Akihiro GODA, Toshihiko HATA

1987 Volume 73 Issue 10 Pages 1419-1424
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1419

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In the emission spectrometric analysis of steels, the influence of surface structure and microstructure on an analytical result and its prevention were investigated. The followings were obtained.
(1) The analytical precision was markedly influenced by the presence of surface oxidized layer but not by the surface roughness.
(2) Microstructural effect on analytical results was found to be due to the unusual emission caused by preferential discharge into pearlite. This effect was remarkable in the analysis of carbon.
(3) The preferential discharge was improved by the rapid formation of electrical discharge hardening layer, which was achieved by the prolonged preburn time or the discharge with high energy spark.

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[title in Japanese]

[in Japanese]

1987 Volume 73 Issue 10 Pages 1442
Published: August 01, 1987
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.73.10_1442

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