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Koji KAMIYA, Kazuyuki SAKURAYA, Isao MORINAKA, Nobuyasu KITAHARA, Masa ...
1979 Volume 65 Issue 2 Pages
169-175
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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An investigation was carried out to obtain the stabilizing conditions for the flow of solid particles in a continuous fluidized bed both with overflow pipes and partition plates, using a cold model made of glass.
(1) Amounts of gas introduced into overflow pipe, when
l>
l'>7.5,
qb≥
qmf and
qc≥
qmf were given by the following equations.
In batch operation, In continiuous operation,
qb=
Qp (
d'/
D)
2ψ
b.
In continiuous operation,
qc=
Qp (
d'/
D)
2ψ
c-
F/ρ
s (1-ε
f) ·10
3It was suggested that
qc must be nearly equal to
qmf in order to maintain the stabilization of gravity flow of solids through the overflow pipe.
(2) The pressure difference, at a level, between the beds separated by a partition plate was decreased with increasing the height above the gas distributor.
In order to minimize the height difference in these two beds, the partition plate with a slit at lower level was effective.
(3) It was suggested that the overall solid mixing behavior in two fluidized rooms, separated by the partition plate with a partially formed moving bed of solid particles, was similar to that expected for two complete mixing stages in series.
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Kazuyuki SAKURAYA, Nobuyasu KITAHARA, Isao MORINAKA, Koji KAMIYA, Masa ...
1979 Volume 65 Issue 2 Pages
176-184
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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For stable operation of continuous fluidized bed reduction of iron ore at high temperature and pressure, fluidizing conditions of iron ore particles of a wide size distribution were investigated using a fluidized bed model at room temperature.
At a certain fluidizing velocity it was possible to maintain these iron ore particles of the wide size range at good fluidization, in which the particle size distribution in bed was almost uniform during the continuous operation and the dust from the bed was a little in the amount. On the basis of this suitable fluidizing velocity obtained from the experiment of a cold model, fluidizing velocities corresponding to the change of factors such as temperature, gas composition, and reduction degree of iron ore were calculated.
The controlling method of the flow rate of reducing gas and gas pressure in the reactor in a continuous operation from the start up at room temperature to the steady state at high temperature was devised.
According to this controlling method, the continuous operation of a pilot plant using nitrogen and hydrogen as fluidizing gas was performed at high temperature and pressure.
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Isao MORINAKA, Koji KAMIYA, Kazuyuki SAKURAYA, Nobuyasu KITAHARA, Masa ...
1979 Volume 65 Issue 2 Pages
185-194
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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In order to develop a direct reduction process by fluidized bed, experimental operations of a pilot plant were carried out. The plant comprised multiple fluidized beds with both counter current and cross current contacting of ore and gas in a reactor of 25 cm inner diameter.
The results are summarized as follows.
1) Stable and sintering-free continuous operation at a maximum temperature of 900°C was carried out, using coarse particles of Hamersley iron ore (16-115 mesh) under pressure of 7 kg/ cm
2G; the product of a reduction of above 95% was obtained, the utilization of hydrogen gas was 17%, and productivity was 55 t/m
2d.
2) The distribution of fractional reduction in a fluidized bed was surveyed by magnetic separation of samples obtained from the bed. Reduction rate of particles in the bed was obtained directly from the distribution curve. An operation analysis was made on this information of particle reduction.
3) Operations using a partition plate designed by the authors were successful and effective to increase reduction of products and productivity.
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Akira SATO, Kazuo KASAHARA, Ryuichi NAKAGAWA, Shiro YOSHIMATSU, Akira ...
1979 Volume 65 Issue 2 Pages
195-202
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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Rate of melting of partly reduced iron pellets into iron melt was obtained by measuring CO gas evolved. The effects of composition of pellets as well as temperature and carbon content of iron melt on their melting rate into the melt have been investigated. The following results are obtained:
(1) Apparent activation energy of melting of reduced iron pellets containing 0, 10, 20 and 40% Fe
2O
3 was 33 kcal/mol.
(2) Without slag melt on the iron melt, the maximum melting rate of pellets containing 10, 20 and 40% Fe
2O
3 was obtained at about 3.3, 3.0 and 2.5% carbon contents respectively.
(3) Melting rate was proportional to -0.5 power of Fe
2O
3 content at the range of 15-60%Fe
2O
3, increased at 2-10% Fe
2O
3 and decreased above 70% Fe
2O
3.
(4) CaO, CaCO
3 or C of 2-5% as addititive increased the melting rate of pellets, but addition of Al
2O
3 or SiO
2 decreased it extremely. Simultaneous addition of CaO and SiO
2 (CaO/SiO
2=1) and addition of pre-fused slag whose melting point was low decreased the melting rate slightly up to 5%, and their content in pellets should be limited within 15%.
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Cases Taking Account of Diffusion in Solid Phase or Diffusion Boundary Layer
Shigeo ASAI, Iwao MUCHI
1979 Volume 65 Issue 2 Pages
203-211
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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The effective distribution coefficients for solidification proposed hitherto are classified according to the morphology and the solidifing condition. In this paper, two cases for the solidification accompanied with a liquid and solid region have been theoretically analyzed by taking account of the diffusion in solid phase (case XII) or the diffusion boundary layer in front of the liquid and solid region (case XIV). In these cases, four kinds of effective distribution coefficient which were defined in the previous paper are represented by the theoretical formula. The representative effective distribution coefficient (
K*
3), which is the solid composition divided by bulk liquid composition, is formulated in the both cases as follows:
K*
3=
K {1-
A/ (Le) 2-
K (1+τ) -2}
case XII
K*
3= {1+1-exp (-
Rδ/
Dl) /Le (1-
K/2) -1·
AK/2}
K/
K+ (1-
K) exp (-
Rδ/
Dl) -
AK/ (Le) (2-
K) -2
case XIV
Furthermore, by the use of the analytical results, the data concerning the macrosegregations in uni-directionally solidified Al-Ag alloys reported by the other authors are analyzed. The theoretical results have been in good agreement with the experimental data.
In comparison with the two extreme cases for diffusion coefficients in solid phase,
Ds=0 and
Ds=∞, in the solidification accompanied with liquid and solid region, the effects of the diffusion in solid phase are given quantitatively.
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Michinori TAKANO, Kazuhiro TERAMOTO, Takenori NAKAYAMA, Hisashi YAMAGU ...
1979 Volume 65 Issue 2 Pages
212-218
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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An extremely slow strain rate testing machine for stress-corrosion cracking (SCC), which can be continuously controlled with cross-head speeds over the range of 1.5×10
-5cm/s to 7.7×10
-9cm/s, has been newly devised and constructed.
Stress corrosion behavior of Type 304 stainless steel in 143°C 42%MgCl
2 at the potential of-0.34 V (SCE), and of Inconel 600 and Incoloy 800 in 140°C 50%NaOH at the potential of 0 V (SCE) was examined by the newly devised testing machine.
SCC was observed to occur most severely at a strain rate of 3.3×10
-6 s
-1 for 304 stainless steel and 1.7×10
-6 s
-1 for Inconel 600 and Incoloy 800, and the susceptibility decreased at strain rates faster or slower than those for all specimens tested. For 304 stainless steel transgranular cracking was formed at the region of slower strain rates and intergranular at faster strain rates but the reverse was the case for Inconel 600 and Incoloy 800.
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Keisuke ISHIKAWA, Norio MARUYAMA
1979 Volume 65 Issue 2 Pages
219-225
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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Mechanical tests were carried out on high manganese austenitic iron alloys for cryogenic service to study the effect on the strength and the toughness at lower temperatures. Addition of manganese to austenitic Fe-Cr-Ni alloy can improve neither the strength nor the toughness. Impact energy decreases as manganese content increases. Although homogenization at 1000°C (1273K) for 24 hours gives rise to coarsning of the grain size, the proof stress and the toughness are remarkably improved. The improvement would be attributed to solution of carbides, which would be nucleation sites for void formation in ductile fracture. In this experiment, 30%Mn-5%Ni-15%Cr and 20%Mn-10%Ni-15%Cr iron alloys are recommended as cryogenic structural materials from the view point of the stability of austenitic phase at 4 K. However, the higher nickel alloy results in the better balance of strength and low temperature toughness than the higher manganese alloy.
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Yukito HAGIWARA, Hiroshi MIMURA
1979 Volume 65 Issue 2 Pages
226-234
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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The effect of plate thickness on fracture toughness in terms of
J-integral concept,
Jc, has been investigated using a heavy section A533B steel (165mm in thickness) which has highly uniform toughness in thickness direction except for surface layer. Notched bend specimens were prepared from this uniform region by varing thicknesses from 3mm to 100mm in order to minimize the metallurgical effects and tested at various low temperatures.
The results are summarized as follows:
(1) A new, simple technique of
Jc estimation is proposed. According to this method,
Jc values can be easily obtained using only the information from COD test which is represented by fracture load and critical clip gage displacement.
(2) There exists an evident effect of plate thickness on fracture toughness in cleavage fracture. Using
KC which is converted from
Jc, the effect is formulated as follows:
KIC=
KC/ (1+2.3β
C)
1/
2, β
2C= (
KC/δ
Y)
2/
Bwhere
KIC is plane strain fracture toughness and
KC is fracture toughness at plate thickness of
B. δ
Y is yield stress.
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Makoto HIMENO, Koji SHIBATA, Toshio FUJITA
1979 Volume 65 Issue 2 Pages
235-244
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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The effects of morphology, size and stability of reversed austenite (γ
rev.) on the mechanical properties have been investigated in very low C-high Ni-Steels with particular reference to the Widmanst@/au56/@tten-like γ
rev. (γ
W). The main results are summerized as follows:
(1) Precipitation of γ
W caused increase of tensile strength and yield strength of steels investigated.
(2) Strengthening by the precipitation of relatively stable γ
W was detrimental for the increase of ductility at low temperature, which is the characteristic of low C-Ni-Steels.
(3) When the stability γ
W was relatively low, the high ductility at low temperature was obtained together with remarkable strengthening by γ
W.
(4) Increase of absorbed energy together with some strengthening was observed in the steels in which small amounts of very fine γ
W precipitated.
(5) The marked strengthening by the precipitation of a large amount of γ
W decreased absorbed energy. Precipitation of (γ
LB) along the lath boundaries did not cause remarkable increase of hardness but the decrease of absorbed energy by large amounts of γ
LB was smaller than that by γ
W.
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Yoshikazu SUZUKI, Kastumasay ABE, Yasunari NISHIKAWA, Keizo NISHIDA
1979 Volume 65 Issue 2 Pages
245-253
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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Oxide (SiO
2 orAl
2O
3) particles were cmbeded to iron powder, and they were pressed, sintered at 850°C for 1 hr in a hydrogen atmosphere, rolled and annealed. The recrystallized grain size and the textures of the sheets were examined, and the reiatienship between these characteristics and tensile properties of the sheets were discussed.
Effects of fine oxide particles added (amorphous SiO
2 and γ-Al
2O
3: about 200Åφ) on the mechanical properties of the sheet were found to be remarkably high comparing with those of larger size (α- SiO
2and α-Al
2O
3: about 2μmφ). In this case, the elongation decreased in general owing to fine recrystallized grain size in the matrix, although its increase appeared in the range of 0.4-0.7 vol. %addition in iron sheets. This fact suggested that the elongation was affected by the annealing texture which had been changed by additive content in the sheet.
As a result, it was found that the dispersed oxide particles and the restraint of recrystallization of the sheet by these particles improved the strength of the sheet, and exerted a major influence on the other mechanical behaviours. Moreover, it was considered that a compound was formed at the inter-face between iron and oxide (SiO
2 or Al
2O
3) during the sintering process.
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Joo ISHIHARA, Masaichi NAGAI
1979 Volume 65 Issue 2 Pages
254-263
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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Micro-bending test and microscopic examination were carried out on high carbon high vanadium iron alloys prepared by melting and by over-laying method, in order to study the effects of size and distribution of V-carbide on the bending strength of the alloy. V-carbides in the specimens were controlled from 21 to 55% in volume and from 2 to 100 μm in diameter, dispersing in matrix of the ferrite, austenite and martensite. It was observed that cracks originated in the carbide phases due to a stress concentration, and was propagated iuto the matrix. The strength of the alloy was more in fluenced by the size than the amouut of the carbide. The cleavage fracture occurred partly in alloys containing much amount of V-carbide, even if the matrix was fully annealed.
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Keisaku YAMADA, Eiichi KATO
1979 Volume 65 Issue 2 Pages
264-272
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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The activities of P and Fe in a dilute solution of P in liquid iron at 1600°C have been determined with a combination of a mass spectrometer and a Knudsen cell; a magnetic deflection type mass spectrometer was used. A pulse counting system was used for the measurement of the ion currents of P
+ and P
+2, for the intensities of these ions were very small; the relatively large ion currents of Fe were measured with a DC amplifying system. The whole system was computer-controlled, and a high sensitivity with a large dynamic range and considerable resolution could be obtained by using this system.
The range of the concentration of phosphorus was from 0.7wt% to 3.2wt% (1.3at% to 5.7at%), and the method based on the G
IBBS-D
UHEM relation was used to obtain the interaction coefficient, ε
PPfrom the obtained ion current ratios, and ε
PP= 7.3±0.1was obtained.
The accuracy and the precision of the obtained value are discussed.
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Keisaku YAMADA, Eiichi KATO
1979 Volume 65 Issue 2 Pages
273-280
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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The interaction coefficients for phosphorus have been determined in the Fe-P-i systems at 1600°C. The experimental technique is the same as described in the paper on the Fe-P systems which was reported previously. The measured systems are Fe-P-Si, Fe-P-Al, Fe-P-Ti, Fe-P-V, Fe-P-Cr, Fe-P-Co, Fe-P-Ni, Fe-P-Nb, and Fe-P-Mo.
The experimental results show that the interaction coefficients for phosphorus with the elements in the fourth and fifth periods increase with the atomic number of the elements.
The results obtained are summarized as follows:
ε
SlP=12.6±0.6 (11.9±0.6)
ε
TlP=-8±2
ε
CrP= -3.8±0.7
ε
NlP= 0.7±0.7
ε
MoP= 0.4±0.7
ε
AlP= 4.6±0.7
ε
VP= -4.9±0.7
ε
CoP= 0.9±0.7
ε
NbP= -5.4±1.2
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Takayoshi YOSHINLORI, Norio KATOH, Masabumi SUGIYAMA, Makoto EBIZUKA, ...
1979 Volume 65 Issue 2 Pages
281-285
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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The nonaqueous titrimetric method for the determination of microamount of CO
2 was introduced to determine oxygen in steel. Carbon monoxide extracted from a sample by the usual carrier-gas fusion method was oxidized with CuO at 750°C, and the dioxide produced was absorbed with N, N-dime-thylformamide containing 5% of monoethanolamine, and then titrated with the standard solution of tetra-n-butylammonium hydroxide in benzene-methanol. Satisfactory results could be obtained especially for the samples of low oxygen-contents. Sucrose was next investigated as a reference material to calibrate the instruments for the determination of CO or CO
2. The definite amount of its standard solution was taken into a small gold boat and evaporated at 50°C in vacuo. The boat was then introduced into a small-mouthed graphite crucible heated at 1 900°C. Stoichiometric recovery of oxygen from the sucrose could be obtained under nearly the same extracting conditions as those for oxygen from steel samples. Thus, sucrose may be used as the reference material in order to calibrate the instruments for the analyses of both oxygen and carbon.
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Kiichi NARITA, Akitsii TOMITA, Nozomu KATAGIRI
1979 Volume 65 Issue 2 Pages
286-288
Published: February 01, 1979
Released on J-STAGE: March 25, 2010
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The general and shortened material balance equations for the LD converter process are derived by using linear mathematical expressions. By solving these simultaneous equations properly, we can obtain the reacted weights of metal phase components and some other unknown weights of dissolved raw materials. The solutions thus obtained satisfy the material balance equations for all constituents that are taken into consideration. The solutions can be applied in many theoretical discussions for the LD converter process.
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Shotaro ARAKI
1979 Volume 65 Issue 2 Pages
289-299
Published: February 01, 1979
Released on J-STAGE: March 25, 2010
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Toshio IKESHIMA
1979 Volume 65 Issue 2 Pages
300-310
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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Mitsuru TATE
1979 Volume 65 Issue 2 Pages
311-314
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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[in Japanese]
1979 Volume 65 Issue 2 Pages
315-316
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]
1979 Volume 65 Issue 2 Pages
317-318
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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1979 Volume 65 Issue 2 Pages
N38
Published: 1979
Released on J-STAGE: February 22, 2010
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[in Japanese]
1979 Volume 65 Issue 2 Pages
A1-A16
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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-
[in Japanese]
1979 Volume 65 Issue 2 Pages
A17-A40
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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-
[in Japanese]
1979 Volume 65 Issue 2 Pages
A41-A60
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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-
[in Japanese]
1979 Volume 65 Issue 2 Pages
A61-A84
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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-
[in Japanese], [in Japanese]
1979 Volume 65 Issue 2 Pages
A85-A116
Published: February 01, 1979
Released on J-STAGE: February 22, 2010
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