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バーチャルイシュー
66 巻, 3 号
選択された号の論文の16件中1～16を表示しています
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磯部 光利, 鈴木 吉哉, 館 充, 北川 英夫1980 年 66 巻 3 号 p. 307-316
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスA miniature bending test method was developed for measuring mechanical properties of coke with better accuracy. Mechanical properties of formed and conventional cokes at room temperature were measured by this method and the effects of pore on them were investigated, taking statistics into consideration. Deformation of a porous body was analysed by the finite element method combined with Monte Carlo method and an attempt was made to develop a method to estimate Young's modulus of coke matrix.
The results are as follows.
1) Linear correlation was found between Young's moduli of cokes and maximum bending stress and a possibility of estimating the strength from the measurements of elastic deformation was shown.
2) Young's modulus of coke decreased with increasing porosity. The decreasing rate of formed coke was different from that of conventional cokes.
3) Young's modulus of coke matrix was estimated by the new method from apparent Young's moduli including the effects of pores.
4) From a new viewpoint a comparison was made between the mechanical properties of formed coke and that of conventional one, using the Young's moduli of coke matrix obtained as above.抄録全体を表示PDF形式でダウンロード (3387K) -
上野 英生, 館 充, 大蔵 明光1980 年 66 巻 3 号 p. 317-325
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスThe dehydration and reduction behaviour of cement bonded cold pellets and their effects on the cold and hot strength were investigated.
The results are as follows.
(1) The dehydration of cement bonded cold pellets begins to proceed at about 320°C and the compressive strength at room temperature decreases remarkably after the dehydration at above 600°C, and it increases after the complete dehydration at 900°C, probably owing to the sintering of materials in the pellets.
(2) The reduction of cement bonded cold pellets is generally faster than fired pellets at above 900°C because of larger chemical reaction rate constant, which, naturally, depends on the reducibility of raw materials and may be affected by some structural factors peculiar to cold bonding.
(3) At high temperature, cement bonded cold pellets tend to deform more easily than fired pellets and the highter reduction degree and temperature is, the more remarkable the deformation is. It is necessary to define hot strength taking the deformation into account.
(4) The hot strength of cement bonded cold pellets partially reduced at 700°C800°C is lower than that of fired pellets, but the difference in the hot strength becomes very little after the complete reduction at 900°C1 000°C.抄録全体を表示PDF形式でダウンロード (1408K) -
成田 貴一, 前川 昌大, 出口 幹郎, 斎藤 武文1980 年 66 巻 3 号 p. 326-335
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスAn investigation on the distribution of MgO in the constituents of the self-fluxed pellets containing MgO was carried out by means of X-ray microanalysis and optical microscopy.
The results obtained were as follows:
(1) MgO content in magnetite was not always higher even if the chemical analysis of MgO of the pellets was higher, but depended rather on the FeO content of the pellets. Namely, magnetite contained 12.618.4% MgO and 4.57.0% MgO in the cases of FeO content of 0.271.45% and 2.606.74%, respectively.
(2) Observed MgO contents in the four phases in the pellets (MgO : 0.36.5%, FeO : 0.276.74%), were as follows : magnetite : 4.518.4%, Ca-ferrite : 0.86.0%, slag : 06.0%, and hematite: 0%.
(3) The magnetite phase in the self-fluxed pellets used in the blast furnace of Kobe Steel, Ltd. was proved to be a solid solution whose composition range was (Fe0.1Mg0.9)O·Fe2O3(Fe0.4Mg0.6)O·Fe2O3.抄録全体を表示PDF形式でダウンロード (12226K) -
高橋 礼二郎, 黒豆 伸一, 高橋 愛和1980 年 66 巻 3 号 p. 336-345
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスIn order to clarify the reduction behaviour of iron oxide pellets at high pressures, a single iron oxide pellet was experimentally reduced with the mixtures of hydrogen and carbon monoxide at 1 000°C. The results obtained were analized by a mathematical model representing the reduction rate of a single iron oxide pellet with the mixtures at high pressures.
The reduction rate equation of pellets with the mixtures was derived from the three-interface core model on the basis of following assumptions: the reduction rate may be calculated by summing the reaction due to hydrogen and carbon monoxide with the pellet and these reactions proceed independently. In this model, the rate parameters were determined by the reduction of the pellet with hydrogen or carbon monoxide independently. However, diffusion coefficients were evaluated as binary diffusion of hydrogen and carbon monoxide.
The calculated reduction curves based on the rate equation were found to be in a relatively good agreement with observed curves over the range of gas concentrations, temperatures, and pressures examined. It was found that the reduction rate equation in the paper could be applied to the analysis of the reduction process with mixtures of hydrogen and carbon monoxide at high pressures.抄録全体を表示PDF形式でダウンロード (3260K) -
佐々 健介, 長 隆郎, 井上 道雄1980 年 66 巻 3 号 p. 346-353
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスThe rates of sulfur transfer from gas phase to the liquid slags in the presence of liquid iron under reducing atmosphere were studied. In the present work, Ar-H2S gas mixture was introduced over slags as CaO-SiO2 and CaO-SiO2-Al2O3-slags at 1 550°C.
The results obtained are summarized as follows:
1) Although the sulfur transfer from Ar-H2S gas mixture to liquid slags is independent of the presence of liquid iron, the rate of sulfur absorption of acidic slags increases gradually as the reduction of silica in those slags proceeds.
2) When the slags are acidic, it is observed that sulfur transfers into liquid iron through those slags and then returns to slags after the maximum concentrations are attained.
3) Rate of silicon transfer from slags to liquid iron increases with increasing sulfur absorption of slags from gas phase, because the reaction of sulfur absorption of slag accompanies the consumption of oxygen ions in those slags.抄録全体を表示PDF形式でダウンロード (1070K) -
拝田 治, 江見 俊彦, 河西 悟郎, 内藤 雅夫, 森脇 三郎1980 年 66 巻 3 号 p. 354-362
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスSolute segregation, and constitution and distribution of inclusions in Ca and/or RE treated continuously cast steel slabs have been investigated as a function of concentrations of Ca, RE, S, and 0. Derivation of an atomic concentration ratio, ACR, of effective Ca or RE to S has been made on the basis of commercial scale experiments. Sulfide shape control is insufficient throughout the slabs at ACR of 0.2 and becomes satisfactory at 0.4 except for center-line segregates. This is in accordance with the previous observation for large ingots. Also, sulfide shape control in the center-line segregates has been found to become insufficient with increasing degree of segregation, because the amount of MnS in the segregates increases with increasing solute segregation ratio. This observation is interpreted quantitatively by the decrease due to the precipitation of CaS and/or RES of concentrations of effective Ca and/or RE in the interdendritic melts in the mushy zone during solidification.抄録全体を表示PDF形式でダウンロード (1291K) -
谷口 尚司, 渡辺 実, 菊池 淳, 只木 〓力1980 年 66 巻 3 号 p. 363-371
発行日: 1980/03/01
公開日: 2010/01/19
ジャーナル オープンアクセスExperimental studies have been carried out in order to examine the applicability of Lavers' model to the electromagnetic fields in the laboratory-scale induction furnace with high frequency.
The furnace used is made of 14 turn 0.054 m-radius and 0.14 m-height induction coil and power supply with frequency of 9.09 kHz or 480 kHz.
Magnetic flux densities have been measured under the conditions without load, with a long copper cylinder load, and with a mercury pool load, respectively. These values have been well consistent with Lavers' model.
Joule's heats have been measured for the following metals : copper, zinc, tin, lead and mercury. These values have been well consistent with the model in the range of r1/δ from 4 to 100, where r1 is the radius of load and δ is the skin depth.
From these results it is possible to apply Lavers' model to the electromagnetic fields in molten iron in a laboratory-scale induction furnace.抄録全体を表示PDF形式でダウンロード (1213K) -
鈴木 良和, 佐山 惣吾, 西田 恵三1980 年 66 巻 3 号 p. 372-381
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセス脈石鉱物を含んだ還元鉄粉を粉末冶金用原料として使用する場合の実用的な見通しを得ることを目的とし,純鉄粉とヘマタイトまたは異種酸化物ならびに流動還元で得られた還元鉄粉の混合圧粉体を加工し,得られた焼結鉄圧延焼なまし板における脈石成分の分布と組成,ならびにこれらの機械的性質への影響について検討した.その結果をまとめると次のとおりである.
(1)脈石成分を5.0wt%(酸素含有量:1.8wt%)含有する還元鉄粉と純鉄粉の混合圧粉体から焼結鉄圧延板を製造する場合,混合量が50wt%(酸素含有量:約1.0wt%)を越えると板材にする過程で割れを生じる.(2)焼結鉄圧延焼なまし板中の脈石成分は,圧延面に平行な薄い板状の分布を示し,圧延方向に伸びており,おのおのの金属酸化物がその中で共存または点在している.(3)焼結鉄圧延焼なまし板中に酸化鉄を含有するものは強度増加と伸び率減少におよぼす影響は認められるが,焼結および焼なまし中の酸化により酸素含有量を増加させてもその効果は少ない.(4)脈石成分を含む還元鉄粉を混合したものは,低い温度で焼結し圧延後の焼なましをしたほうが強度増加への影響は大きい.その原因の一つとして圧延加工による酸化物の微細化と分散の促進があげられる.(5)これら圧延焼なまし板の引張り後の破面は,脈石成分の少ない場合は塑性変形をともなう延性破壊面であり,脈石成分が多いものはら密な層状組織の断面にそつてき裂が伝播した破断面となる.抄録全体を表示PDF形式でダウンロード (17360K) -
峯村 哲郎, 井上 明久, 増本 健1980 年 66 巻 3 号 p. 382-389
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスBy rapid quenching technique, nonequilibrium austenitic alloys with high strength and hardness have been found in Fe-Cr-C ternary system. This formation region is limited to about 1.02.2 wt%C and 730 wt%Cr. The austenite phase has ultra-fine grains of about 0.2 μm in diameter. Their Vickers hardness, 0.2% proof stress and tensile fracture strength increase with increase in the amounts of C and Cr, and the maximum values attain about 630 DPN, 1 500 MPa and 1 550 MPa, respectively.
These alloys are so ductile that no crack is observed even after closely contacted bending test. In addition, the changes in microstructure and mechanical properties of the tempered austenitic alloys have been investigated and it has been observed that a large secondary hardening occurs at about 870K due to phase transformation from austenite to equilibrium structure of ferrite and M7C3 pearlite.
Thus the present alloys may be attractive as a high-strength wire or plate.抄録全体を表示PDF形式でダウンロード (9054K) -
山本 優, 宮川 大海, 小林 光征, 藤代 大1980 年 66 巻 3 号 p. 390-399
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスThe creep rupture properties of 21Cr-12Ni austenitic heat resisting steels containing various content of carbon and phosphorus have been investigated on the basis of grain- and grain boundary-strengths.
The addition of phosphorus promotes the homogeneous precipitation of M23C6 carbides inside grains an deceases the minimum creep rate. The strength of grains evaluated by the minimum creep rate depends mainly upon the phosphorus content. On the contrary, the strength of grain boundaries evaluated by the grain boundary configuration depends mainly upon the carbon content.
The rupture strength of steels having straight boundaries is improved with the increase in phosphorus content owing to the increase in the strength of grains. The phosphorus addition above about 0.25%, however, is not effective to improve the rupture strength because of the poor grain boundary strength of these steels. On the other hand, in the steels having stronger zigzag boundaries, the higher the phosphorus content, the higher the rupture strength. Moreover, the rupture strength of the latter is always higher than that of the former regardless of phosphorus content.
It is emphasized that the optimum content of carbon and phosphorus should be considered from a point of view of the harmony of grain-and grain boundary-strengths.抄録全体を表示PDF形式でダウンロード (7019K) -
梅本 実, 小松原 望, 田村 今男1980 年 66 巻 3 号 p. 400-409
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスAs a first step to obtain a theoretical prediction of hardenability based upon the theories of phase transformation, the effect of austenite grain size on the hardenability of eutectoid steel is examined.
The effect of austenite grain size on the isothermal pearlite transformation curves were first measured.
The obtained results were analysed according to the Cahn's theory and the volume fraction of pearlite can be expressed as X=1-exp(-1.31×10-5×t4/d1.76). This result indicates that the pearlite transformation in the steel in present study procceeds by nucleation and growth and dominant nucleation site is grain edge. Step quenching experiments indicates that additivity rule is almost holds.
Using these experimental data, the effect of austenite grain size on the ideal critical diameter was calculated as DI ∝ d 0.22. The relation between the ideal critical diameter and the diameter of the bar having any amount of martensite at the center is also calculated.抄録全体を表示PDF形式でダウンロード (3986K) -
古川 徹, 小沼 静代, 酒庭 秀康, 春谷 忠1980 年 66 巻 3 号 p. 410-417
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスFor various kinds of carburized case depths in SCM-21, both smooth specimens and notched specimens with various notch shapes were tested under the rotating bending fatigue to evaluate the fatigue strength properties of carburized steel. The main results obtained are as follows : (1) The maximum value of the crack initiating stress σW1 and of the crack propagating stress σW2, namely, the maximum fatigue strength at 107 cycles, were obtained for notched specimen as well as the maximum fatigue limit σW0 for smooth specimen in the case of the specimen with effective carburized case depth of about 0.91.2 mm, corresponding to 1824% of the half the diameter of the specimen. (2) The existence of the non-propagating crack at 107 cycles was observed in the case of the notched specimens with the notch depth of t≥0.24 mm and the notch root radius of ρ=0.08 mm. (3) The following equation was found to hold between the nominal crack propagating stress at the crack tip σ'2W and the effective crack length leff·σ'nW2·leff=Const.
The exponent n determined was 7.2 for specimen A, 14 for specimen B and 22 for specimen C. (4) For smooth specimen, the appearance of the fish-eye pattern was observed on the fractured surfaces in the case of the specimen with the effective carburized case about 1.0 mm or less deep, but could not be certainly observed in the case of the craburized case depth exceeding 1.2 mm.抄録全体を表示PDF形式でダウンロード (6010K) -
四竈 樹男, 田辺 龍彦, 藤塚 正和, 吉田 平太郎, 渡辺 亮治1980 年 66 巻 3 号 p. 418-424
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセス原子力直接製鉄に使用されるガスの近似還元ガス,80%H2+15%CO+5%CO2(試験還元ガス)中での,材料試験に伴う問題点を検討した.試験還元ガスの高温でのガス反応に伴う煤及び水分の発生には,金属表面が触媒として市要な働きをしており,恒温槽に石英を使用することは,煤,水分発生の抑制に有効である.
また,ニッケル基耐熱鋳造合金MO-RE II 上に,BN-SiO2を塗付することにより,煤,水分の発生は十分に抑制される.
試験還元ガス中でのCA熱電対の劣化に対しても,BN-SiO2の塗付は有効であることが認められる.
しかしながら,1000℃,1000h以上のクリープ試験に対し,発生したH2OとBNとの間での反応により,NH3の生成が認められ,このことはBN-SiO2被覆の使用の限界を示唆する.
試験は,ここに示したシステムを使用し,900℃,2900hまでの連続連転が,安全に遂行されている.抄録全体を表示PDF形式でダウンロード (4454K) -
堀尾 正靱, 鞭 巌1980 年 66 巻 3 号 p. 425-426
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスA theoretical analysis was made to determine the temperature gradient in the cooling zone of the heat wave of iron ore sintering. The temperature gradient is strongly dependent on the effective heat exchange area which changes with the fusion of bed material. A simple chart was presented to estimate the heat transfer capacity coefficient hpa from observed cooling rate or vice versa. The coefficient hpa and the corresponding effective grain size were estimated from the observed temperature gradients reported in the literature.抄録全体を表示PDF形式でダウンロード (282K) -
林 国一, 山本 晃1980 年 66 巻 3 号 p. 430-437
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスPDF形式でダウンロード (3555K) -
月橋 文孝, 小林 一彦, 壇 武弘, 木下 勝雄, 郡司 好喜, 檀 林三, 北岡 英就, 村上 雅人, 西脇 健一, 辻川 茂男1980 年 66 巻 3 号 p. 444-447
発行日: 1980/03/01
公開日: 2009/06/19
ジャーナル オープンアクセスPDF形式でダウンロード (666K)
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