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64 巻, 6 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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金子 伝太郎, 木村 吉雄, 小野田 守1978 年 64 巻 6 号 p. 681-690
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスIn the direct reduction shaft furnace it is favorable to raise reducing gas temperature blown from tuyeres to improve not only the productivity but also characteristics of the sponge iron for reoxidation. However, if the operating temperature is too high, the material become sticky and form so called clusters. Thus authors investigated clustering behavior of iron oxide during its reduction by a laboratory test.
Pellet with iron content of 64-68% and lime (CaO) content of 0.09-1.11% were produced by an indurating furnace of bench scale. Five hundred grams of fired pellets were charged into the reduction tube with inside diameter of 75 mm and were reduced with reducing gas (H2: 55%, CO: 36%, CO2: 5%, CH4: 4%) under load at a temperature range of 700-960°C. The expansion or shrinkage ratio of the sample bed was continuously recorded using a strain gage. The strength of clusters formed during reduction was measured in a rotating steel drum with diameter of 120mm and length of 700mm. It was found that the shrinkage ratio of the pellet bed was clearly related to the cluster, and the higher the shrinkage ratio, the stronger the cluster.
The formation of the cluster during reduction depended on three factors., i. e. the temperature, load on the burden bed and properties of materials. The relationship of these factors as well as clustering mechanism of reduced materials were discussed based on the experiments.抄録全体を表示PDF形式でダウンロード (5475K) -
田口 整司, 槌谷 暢男, 高田 至康, 岡部 侠児1978 年 64 巻 6 号 p. 691-700
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスThe operational data of blast furnace performance for longer periods are analyzed by the following parameters as adiabatic flame temperature, height for heat exchange and height of melting level, as well as indices of the thermal state RSi and the reduction behavior of ferrous oxide RS and RMn at the lower part of blast furnace. The results are as follows.
(1) The temperature of melts changes with the adiabatic flame temperature and height for heat exchange, and is related to the heat balance.
(2) RSi gives the same expression as that for thermal state representing the extent of coke reserve zone.
(3) With lower quality coke, RSi, RS and RMn decrease markedly even in a regular operation; this indicates increasing FeO content in slag at the hearth.
(4) The increase of sulfur content in injected oil decreases the S distribution ratio between slag and metal. On the other hand, the increase of sulfur content in coke has no influence on it. These differences are caused by the transfer mechanism to gas phase.抄録全体を表示PDF形式でダウンロード (2080K) -
長 隆郎, 森谷 徹, 井上 道雄1978 年 64 巻 6 号 p. 701-710
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスThe rates of nitrogen desorption of inductively stirred liquid iron have been measured under reduced pressure at 1600°C and the effects of manganese and copper on the rates are discussed.
The rates of nitrogen desorption are apparently represented by the equation of 2nd order reaction in terms of nitrogen content in liquid iron as shown by the previous investigators under argon atmosphere. The values of the rate constant of nitrogen desorption, kN, decrease with increasing oxygen-content in liquid iron and are nearly agreed with those obtained by other authors at higher concentration range than 0.02%. At low concentrations of oxygen in melts, however, the values of kN obtained in the present work are higher than any of those by the others, though there are some discrepancies among them. These results are explained by the application of the mixed-control model including the mass transfer in both phases and the chemical reaction at the interface. Although the rate of nitrogen desorption has been regarded as the chemical reaction control, the mass transfer in liquid iron may play an important role on the nitrogen desorption at the lower oxygen range. It is also found that the vapourization of manganese or copper in liquid iron decreases the rate of nitrogen desorption, probably because of the local decrease of interfacial temperature due to the latent heat of vapourization and also because of the decrease of the effective reaction site for the nitrogen desorption.抄録全体を表示PDF形式でダウンロード (2059K) -
喜多 善史, 大口 滋, 森田 善一郎1978 年 64 巻 6 号 p. 711-719
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスFor the precise measurement of the electrical resistivity of molten metals at high temperature, the fourprobe method has been improved by use of a newly designed cell in which the four electrodes made of the same material as the specimen were installed.
The results of the preliminary experiment on molten tin and copper were in excellent agreement with those of the previous studies by other investigators, and it was proved that “the improved four-probe method” was quite suitable for the measurement of the electrical resistivity of molten metals at high temperature.
The electrical resistivity of molten iron, cobalt and nickel, obtained in the temperature range from melting point to about 1 660°C (iron) and 1 620°C (cobalt and nickel), showed a linear dependency on temperature as represented by the following equations.
Fe: ρ (μΩ·cm) =0.0154t (°C) +112.3
Co: ρ (μΩ·cm) =0.0192t (°C) +91.8
Ni: ρ (μΩ·cm) =0.0116t (°C) +70.2
Probable error in the measurement was estimated to be about ±0.2%. The ratio of the resistivity of the liquid metal (ρl) to the solid metal (ρs) at melting point was evaluated to be 1.06, 1.14 and 1.40 for Fe, Co and Ni respectively.抄録全体を表示PDF形式でダウンロード (1897K) -
藤澤 敏治, 野村 真, 坂尾 弘1978 年 64 巻 6 号 p. 720-729
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスExperiments on the solid-liquid equilibrium relationship in Fe-Si-O alloys were carried out using the zone melting technique.
The deoxidation constant with silicon in liquid iron was log KSi (l) =-5.18 ([%Si (l)] <0.64) at the solid-liquid equilibrium temperature, which is in good agreement with the values given in the literature.
The silicon-oxygen equilibrium relationship in δ-iron at the solid-liquid equilibrium temperature is represented by the following equations:
log aSi (s) ·aO (s) 2=-7.19 ([%Si (s)] ≤0.5)
log fSiSi (s) =0.086 [%Si (s)]
log fOSi (s) =-15.9 [%O (s)]
log fSiO (s) =-9.05 [%Si (s)] +30 [%Si (s)] 2 ([%Si (s)] ≤0.1)
log fOO (s) ≈0抄録全体を表示PDF形式でダウンロード (2182K) -
浅井 滋生, 小沢 順造, 鞭 巌1978 年 64 巻 6 号 p. 730-739
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスA mathematical model of a channel-type segregation is developed on the basis of the stability theory. By focusing on the difference of the cooling conditions, the instability phenomena inducing the segregation are theoretically analyzed by use of the model.
The analytical results are confirmed by the model experiments. In these experiments, the aqueous solutions of NH4Cl are freezed by cooling from the top or the bottom of a mold having the adiabatic side walls or by cooling through the side walls.
Thermal insulation of the side walls are essential for preventing the channel-type segregation. When a mold is cooled through its side walls, controlled preparation of the alloy elements is required to prevent the formation of segregation.抄録全体を表示PDF形式でダウンロード (9934K) -
福田 実, 国重 和俊, 杉沢 精一1978 年 64 巻 6 号 p. 740-748
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスUsing a laboratory simulation method for producing coiled-strips and plates, a study has been made on the separations occurring at the fracture surfaces of tensile and Charpy specimens of high strength low alloy steel containing 0.04%Nb and 0.09%V. Main results are summarized as follows:
(1) Even by the same rolling process with a finishing temperature of 780°C, the separations of coiledstrips on Charpy specimens are more remarkable than those of plates. Also, separations occur at the fracture surfaces of tensile specimens for coiled-strips, although they can hardly be observed in case of aircooled plates.
(2) The plates which are air-cooled to room temperature and then tempered at the temperature similar to that of coiling, show the separations on tensile specimens.
(3) The separations in coiled-strips are accelerated by temper-embrittling elements such as phosphorus or manganese, and are reduced by molybdenum which is known to be the suppressing element for temperbrittleness.
(4) For coiled-strips, the separations are found to closely correlate with the layer of segregation of phosphorus, and the cracks are mainly through the grain boundary of the ferrite.
(5) From these results, it is concluded that the separations of coiled-strips are caused by temper-brittleness during the slow cooling after coiling i. e., phosphorus in a segregated layer moves to ferrite grain and deteriorates the toughness of the boundaries.抄録全体を表示PDF形式でダウンロード (8508K) -
長井 寿, 柴田 浩司, 藤田 利夫1978 年 64 巻 6 号 p. 749-758
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスTensile testing has been carried out in the temperature range from -196°C to room temperature. Highly tempered martensite (plus fine dispersed retained austenite) microstructure, observed in specimens heated in the vicinity of As temperature, shows the best low temperature ductility. Heating in the vicinity of Af temperature, lath-type fresh martensite with some small recrystallized equiaxed grains is observed and shows relatively a good ductility. On the other hand, a highly recovered ferrite with fresh martensite structure, obtained by heating in the intermediate range of α-γ duplex phase region, yields a poor ductility. All these structures, especially the former two ones, exhibit larger uniform elongation at lower temperature down to -196°C. No trace of martensitic transformation of retained austenite is detected by cooling down to -269°C, but a little plastic deformation at -78°C makes most of retained austenite transform to martensite. Such a transformation induced by deformation is also observed at room temperature. Considering the results of some other Fe-Ni alloys, the interrelationship between low temperature ductility and microstructures of 11%Ni steels is discussed.抄録全体を表示PDF形式でダウンロード (4269K) -
冨田 恵之, 宮本 啓太, 岡林 邦夫1978 年 64 巻 6 号 p. 759-768
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスA study has been made of the strength and ductility of a 0.42% C-Ni-Cr-Mo steel having mixed structure of martensite and bainite.
It was found that lower bainite, which precipitated acicularly so as to partition prior austenite grains, had a desirable effect on the 0.2% proof stress regardless of tempering conditions, but had not necessarily on the elongation. Upper bainite, which precipitated massively so as to fill prior austenite grains, was found to have detrimental effects both on the 0.2% proof stress and elongation irrespective of tempering conditions.
The beneficial effect of lower bainite on the 0.2% proof stress is attributable to the fact that the 0.2% proof stress deviates better from the general law of mixture, it resulting from the improvement of the strength of martensite owing to the refinement of its substructure, besides an increase in the strength of the bainite being due to higher plastic restraining of the bainite by martensite. The detrimental effect of upper bainite on it is attributable to the fact that it deviates worse from the law of mixture being due to ununiform strain of two-phase.抄録全体を表示PDF形式でダウンロード (6042K) -
細谷 佳弘, 井上 明久, 増本 健1978 年 64 巻 6 号 p. 769-778
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスThe effect of hydrogen on the crack propagation behavior and the microstructures around cracks in SUS 304H type and SUS 310 type austenitic stainless steels was examined by means of the tensile tests and microscopic observations. The results obtained are summarized as follows:
(1) For austenitic stainless steels, the yield strength and 2% flow stress are hardly dependent on the hydrogen content, whereas the fracture strain and the total energy on plastic deformation decrease remarkably as the hydrogen content increases.
(2) According to the notch tensile tests, the force for crack initiation does not change with the hydrogen content very much but the elongation by crack opening and the amount of work required for the fracture decrease remarkably with increasing the hydrogen content.
(3) An increase of absorbed hydrogen suppresses the strain induced transformation of α′ martensite, while it promotes the formation of ε martensite due to a lowering of the stacking fault energy by hydrogen.
(4) It is concluded that the hydrogen embrittlement of austenitic stainless steels is mainly due to the formation of ε martensite in the vicinity of cracks by the absorption of hydrogen and the easy propagation of cracks along the boundary between austenite and ε martensite.抄録全体を表示PDF形式でダウンロード (12534K) -
浜野 隆一, 津谷 和男1978 年 64 巻 6 号 p. 779-786
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスThe effect of prestrain on the low-temperature ductility of Fe-1.83%Cu alloywas investigated as a function of prestrain temperature, prestrain quantity, and tensile testing temperature.
Ductility of solution-treated Fe-1.83%Cu alloy at 77K decreased about 20% with increasing prestrain at room temperature, whereas, ductility of aged Fe-1.83%Cu alloy (25h at 700°C) increased about 10% at 120 and 77K, after prestrain of 2.4% at room temperature. However, the ductility did not increase, after any prestrain at 153K.
Dislocation structure produced by prestrain of 2.4% at room temperature was observed, after 5% deformation at 77K for aged Fe-1.83%Cu alloy (96h at 700°C), but not for solution-treated Fe-1.83%Cu alloy.抄録全体を表示PDF形式でダウンロード (7647K) -
堤 信久, 竹内 力1978 年 64 巻 6 号 p. 787-796
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスWith the view of investigating the behavior of embrittlement of blackheart malleable iron, Charpy impact tests were carried out for series of specimens. The influences of phosphorus and/or nitrogen content, quenching temperature, holding time, and cooling rate were studied on the brittleness of these irons. Micro hardness test was also carried out on the ferrite grain interiors and its boundaries of irons subjected to a variety of treatments.
Various kinds of surface analyzers such as IMA, ESCA, and AES are utilized for the analysis of the grain boundary fracture surfaces of the embrittled blackheart malleable iron.
The results obtained are as follows.
(1) Phosphorus has a close relationship to the embrittlement of blackheart malleable iron, while nitrogen appears not to give rise to brittle fracture.
(2) Holding at 450°C results in the embrittlement of the iron.
(3) The reversibility between brittle and ductile fracture is confirmed on the impact values.
(4) Quenching from 650°C before 450°C embrittling treatment retards the appearance of brittle fracture in the iron having higher content of phosphorus.
(5) Micro hardness test shows that an embrittled iron has a little increment of hardness at grain boundary, compared with that of grain interior of the same iron.
(6) The remarkable segregation of phosphorus in the grain boundary of the embrittled iron is recognized by means of IMA, ESCA, and AES analyses.抄録全体を表示PDF形式でダウンロード (5527K) -
遠藤 芳秀, 斉藤 啓二, 中原 悠紀1978 年 64 巻 6 号 p. 797-803
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスInductively coupled high frequency plasma (ICP) -optical emission spectrometry was used for the determination of some elements in steels. The determined elements were Ce, La, Nb, Zr and Al, and the former four ones cannot be determined by the atomic absorption method.
The plasma was generated by the frequency of 27.120 MHz and the output power of 1600 watt. An 1.7-meter Ebert mounting spectrometer was used. Steel samples were completely dissolved by suitable acids, and diluted to the 0.5 wt% in solution level. The acids and the iron present in the sample solution affected slightly the emission intensity of each measuring element, but these interference effects were prevented by adding to the reference solution of the same amounts of acids and iron as in the sample solution.
The determined values by this method closely agreed with the values by chemical analysis. The measuring time of this method for one sample solution was about 40 seconds. As the standard deviation in the micro amount region, 0.00017% for 0.002% Al sol, 0.00006% for 0.005% La, 0.00035% for 0.006% Ce, 0.00012% for 0.011% Nb and 0.00021% for 0.004% Zr were obtained.抄録全体を表示PDF形式でダウンロード (1394K) -
牛島 清人, 渡部 保博1978 年 64 巻 6 号 p. 804-814
発行日: 1978/05/01
公開日: 2010/02/22
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清永 欣吾1978 年 64 巻 6 号 p. 815-822
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスPDF形式でダウンロード (1971K) -
天辰 正義, 月橋 文孝, 雀部 実, 郡司 好喜, 檀 武弘, 水上 秀昭, 石田 寿秋, 菊池 実, 今井 嗣郎, 山下 幸介1978 年 64 巻 6 号 p. 823-827
発行日: 1978/05/01
公開日: 2010/02/22
ジャーナル オープンアクセスPDF形式でダウンロード (1282K)
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