巻号一覧
43 巻, 4 号
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高津 宗吉1979 年 43 巻 4 号 p. 281-286
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーPure tungsten powder and tungsten-cobalt mixed powder were carburized by H2-10%CH4 mixed gas at temperatures from 1073 to 1473 K. In order to examine the carburizing process, tungsten plates were also carburized under similar conditions.
Methan was decomposed by either of tungsten and cobalt, and the larger fraction of methan was decomposed by the tungsten-cobalt mixed powder of a given composition than the total fraction of methan which was decomposed by each powder of tungsten and cobalt equivalent to that in the mixed powder. In carburization of pure tungsten, the deposition amount of carbon corresponded to the amount of carbon diffused into tungsten, and the least amount of free carbon was observed. The amount of free carbon in the mixed powder was higher than that of carbon combined with tungsten at 1073 K, but it decreased as the temperature rose and approached to zero at temperature above 1273 K.
Coexisting with cobalt, the carbide formation rate of tungsten was approximately 2 to 7 times as large as that of pure tungsten, and the effect of cobalt enhance with increase in carburizing temperature. The relation between formation amount of carbide h and carburizing time t was expressed in the form of h=qtp. The value of p was 1⁄2 for pure tungsten. While coexisting with cobalt, the value of p varied from 2⁄3 to 1 where the shift from the parabolic law increased with rising temperature, and the activation energy for formation of tungsten carbide also increased.抄録全体を表示PDF形式でダウンロード (525K) -
高津 宗吉1979 年 43 巻 4 号 p. 286-291
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーThe carbide formation process in tungsten-cobalt mixed powder was investigated by carburizing of tungsten plates. The carbides are formed uniformly at the whole surface of pure tungsten, where W2C and WC are formed succesively and the rate-determining stage is the diffusion of carbon in WC.
While in tungsten covered with cobalt, carbides are formed preferentially at the surface of tungsten being in contact with cobalt. Coexisting cobalt with tungsten M6C(η-W3Co3C etc.) and WC are formed by the reaction of W2C with Co after the formation of W2C, and then WC is formed by the reaction of M6C with C. Cobalt is observed in the M6C layer and at grain boundaries of the WC layer, and it promotes the diffusion of carbon into the inner part of the carbide layer. The rate of carbide forming from tungsten-cobalt mixture deviates from the parabolic law, since the amount of cobalt in the carbide layer increases with the carburizing time and temperature. The rate-determining process of carbide formation in the tungsten-cobalt mixture is the diffusion of carbon in the carbide layer containing cobalt.抄録全体を表示PDF形式でダウンロード (604K) -
下斗米 道夫, 橋ロ 隆吉1979 年 43 巻 4 号 p. 292-295
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーPrismatic punching of rows of dislocation loops in an Al-1.3%Li alloy has been in situ observed in an electron microscope. The coherent Al3Li particles precipitated at 320°C in the electron microscope lose coherency by punching of dislocation loops when the shear stress at the precipitate-matrix interface is sufficiently large. The process of prismatic punching is in accord with the model of Jones and Mitchell. The rows lie in the <110> directions. The spacing of the loops has been analyzed with the theory of Bullough and Newman and a value of the critical shear stress to move a loop has been estimated.抄録全体を表示PDF形式でダウンロード (907K) -
瀬尾 俊弘, 篠原 和充, 熊田 健三郎1979 年 43 巻 4 号 p. 296-304
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーAustenitic stainless steel containing nominally 25%Cr and 20%Ni has been heated to follow the recrystallization process in an ambient atmosphere and the recrystallization kinetics has been studied mainly by transmission electron microscopy. It was found that the activation energy for recrystallization in this material was 4.6×105 J/mol which was considerably greater than the previously reported values and also that boundaries between deformed and recrystallized grains were favorable sites for σ-phase formation, which might have depressed the growth rate of recrystallized grains. The recrystallized grains had the same zone axis as as the surrounding deformed textural grains but they were rotated each other by 52 degrees about the [110] zone axis. The crystallographic orientation relationship between the recrystallized grains and σ-particles was found to be (1\={1}\={1})Rex.γ\varparallel(140)σ,[110]Rex.γ\varparallel[001]σ.抄録全体を表示PDF形式でダウンロード (1943K) -
田中 勇, 大槻 孝, 佐藤 公隆1979 年 43 巻 4 号 p. 304-308
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーX-ray fluorescence analysis was applied to the determination of Si (content:70∼80%) in ferrosilicon and was established as an useful method with good accuracy. The results obtained are summarized as follows :
(1) The technique of briquetting after grinding ferrosilicon with a styrene-maleic acid copolymer (PSM) in an organic solvent is suitable to the preparation of samples for the analysis. After 3g of the ferrosilicon sample is ground with 1g of PSM in 15 ml of n-hexane, a briquet sample is prepared by pressing. (2) Repeatability by this sample preparation is 0.091% as standard deviation or 0.12% as coefficients of variation for 77.30% of Si in ferrosilicon. (3) Calibration curve is shown in a first order revolving formula of Si (%) =0.0230×I+46.697 (I : intensity of SiKα X-ray). (4) In this analysis, the particle size gives a remarkable influence, so that it is important for the ferrosilicon sample to be extracted under a condition as definite as possible and arranged to have uniform particle size. (5) This sample preparation procedure can also be used effectively as an analytical technique for process control.抄録全体を表示PDF形式でダウンロード (696K) -
河原 正泰, 森永 健次, 柳ヶ瀬 勉1979 年 43 巻 4 号 p. 309-315
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーThe behavior of MgO and NiO in PbO-SiO2 melts, respectively, has been investigated through the measurements of electrical conductivity, viscosity and far-infrared absorption spectra.
In the PbO-SiO2-MgO system, the addition of MgO decreases both electrical conductivity and viscosity in the basic slag region (PbO/SiO2=3/2∼2/3) while no such a contribution is found in the acid slag (PbO/SiO2=3/7). These facts can be interpreted as proof that the basicity of MgO is weaker than that of PbO and increases with MgO content. The amphoteric behavior of MgO in the melts is substantiated by the far-infrared spectra of MgO.
In the PbO-SiO2-NiO system, the addition of NiO to the melts of PbO/SiO2=1∼2/3 increases electrical conductivity up to 10 mol% of NiO but decreases it thereafter. In the meanwhile, no such an increasing effect is observed on the viscosity. NiO in the melts behaves as an amphoteric oxide, although it seems to be a rather mild base in the higher NiO region. The far-infrared spectra of the high NiO slag that shows no contribution of NiO to the electrical conductivity is substantially the same as that of pure NiO. This suggests the existence of molecular type of NiO (no dissociation to Ni2+ and O2−) in the melts of the higher NiO region.抄録全体を表示PDF形式でダウンロード (548K) -
向井 楠宏, 小林 一三1979 年 43 巻 4 号 p. 316-320
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーCorrelations between the wettability of Pt with molten silicate and polarization potential \varphi were investigated in argon atmosphere at 1073 K. The following results were obtained. (1) The wettability is improved remarkably with the anodic polarization before hysteresis of contact angle θ versus \varphi appears. (2) In the case of anodic polarization, the correlations between θ and \varphi for PbO-SiO2 melts show smooth curves that have a maximum in the case of SiO2≤33%. In the case of SiO2≥40%, the θ-\varphi curves show a shelf-like form. The width of the shelf increases with increasing SiO2 content. (3) Addition of K2O to PbO-SiO2 (40%) melt shows a tendency to promote the action of PbO on the θ-\varphi curve.抄録全体を表示PDF形式でダウンロード (444K) -
羽木 秀樹, 林 安徳, 大谷 南海男1979 年 43 巻 4 号 p. 320-325
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーThe dynamic interaction of dissolved hydrogen with moving dislocations in electrolytic iron and Fe-Cr alloys was examined by measuring the flow stress and elongation of specimens charged with hydrogen during tensile and creep tests. The cathodic charging with hydrogen also causes internal damage to the specimen due to the precipitation of hydrogen. Therefore, the flow stress varies in a complicated manner with cathodic current density and specimen thickness. In order to elucidate the effect of dissolved hydrogen on the flow stress, the stress-strain curves were analysed taking account of the effect of the hydrogen precipitation. Since the increase in dislocation density due to the hydrogen precipitation is remarkable in the surface layer of the specimen, the influence of the hydrogen precipitation can be negligible in the thick specimens. In thick specimens of electrolytic iron, the increase of the flow stress by the charging with hydrogen is only observed. In Fe-20Cr, the effect of the hydrogen precipitation on the flow stress is negligibly small, and the flow stress also increases with the hydrogen charging. The flow stress increased by the hydrogen charging in Fe-20Cr is restored immediately after interruption of the charging. The flow stress of electrolytic iron and Fe-Cr alloys is increased by the dissolved hydrogen, if the damage due to the hydrogen precipitation is avoided.抄録全体を表示PDF形式でダウンロード (522K) -
野口 文男, 植田 安昭1979 年 43 巻 4 号 p. 326-332
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーThe segregation roasting studies have been conducted for the copper oxide ore from Katanga Mine in Peru by adding small amounts of chlorides and a reducing agent. The effects of roasting conditions such as temperature, heating rate, kinds of chlorides and gas flow rate were investigated in order to clarify the optimum conditions to obtain a high recovery of segregated copper. The results obtained are as follows :
(1) CaCl2, MgCl2 and NH4Cl are more favorable chloridizing agents than NaCl for the copper ore. (2) The most appropriate combinations of kinds of chlorides and roasting temperature for each of the reducing agents are those of CaCl2,MgCl2 or NH4Cl and from 750°C to 800°C for coke I, CaCl2 or MgCl2 and from 800 to 900°C for coke II and NaCl or CaCl2 and 700°C for charcoal. (3) The heating rate in roasting has a considerable influence upon the evolution of HCl gas from chlorides. The higher recovery of segregated copper can be achieved at a lower heating rate for any chlorides. (4) The flow rate of argon gas has no effect on the recovery of copper in the range of 0 to 100 cm3/min under the optimum segregation conditions. (5) An adequate amount of salt addition is 1.6 times the theoretical value with about 3% of the reducing agent. Excess addition of the reducing agents causes a direct reduction of copper oxides, resulting in a low recovery of segregated copper.抄録全体を表示PDF形式でダウンロード (559K) -
末吉 秀一, 末永 勝郎1979 年 43 巻 4 号 p. 333-339
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーThe graphitization reaction at subcritical temperatures has been studied on Fe-C alloy produced by carburizing pure iron and a number of hypo-eutectoid alloy steels containing alloying elements such as silicon, manganese, cobalt and nickel. The TTT relationship for subcritical graphitization resulted in the “C” curve, the nose of which was located at a temperature about 60°C lower than Ac1 of each steel. The more the elements such as silicon, cobalt and nickel which had a partition coefficient in cementite to ferrite smaller than unity, the shorter the incubation time of the graphitization. It was accordingly suggested that the elements in cementite affected the stability of cementite. The graphitization reaction in hypo-eutectoid alloy steels obeyed Johnson-Mehl’s equation and the reaction exponent n was a value close to 2.5, and the activation energies obtained from cross-cut method considering temperature dependency of the number of graphite nodules were 166 to 193 kJ/mol. On the other hand, graphite was found to grow along ferrite grain boundaries. From these results it was suggested that the rate-controlling process for growth of graphite was diffusion of iron along ferrite grain boundaries.抄録全体を表示PDF形式でダウンロード (858K) -
高橋 実, 宮崎 照宣, 渡部 明夫1979 年 43 巻 4 号 p. 339-347
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーEffects of isothermal annealing (125∼490°C, 5∼1300 min) on the magnetic properties, electrical resistivity as well as tenacity have been studied for rapidly quenched amorphous Fe80P13C7, Fe75Si15B10, Co74Si10B16 and Fe5Co70Si15Br10 alloys. The results are summarized as follows :
(1) The magnetic properties of all the alloys change remarkably by the annealing. (2) The coercive force of the alloys is minimum when annealed for about 10∼100 min at the temperatures, about 40∼120°C lower than the crystallization temperatures of the alloys. (3) The hysteresis loops for Co74Si10B16 alloy annealed at 300∼490°C for about 10∼100 min and those for Fe5Co70Si15B10 alloy annealed at 125∼470°C exhibit asymmetrical and unusual shapes. (4) The values of electrical resistivity of these alloys in the as-quenched state are in the range between 160∼240 μΩ·cm. With annealing at various temperatures between 200 and 400°C, no change of electrical resistivity, is observed except for Fe80P13C7 alloy annealed at 400°C. (5) After annealing at around 300°C, Fe80P13C7, Fe75Si15B10 and Fe5Co70Si15B10 alloys become brittle, while the tenacity of Co74Si10B16 alloy is maintained even after annealing at 490°C for 1 h.
In order to know the effect of pre-heat treatment on the stabilization of these magnetic properties, isothermal annealing at around 250°C is carried out for the Co74Si10B16 and Fe5Co70Si15B10 alloys, which have been pre-annealed at 400°C for 30 min. It is found that the magnetic properties of both alloys are not stabilized by this pre-annealing.抄録全体を表示PDF形式でダウンロード (704K) -
大谷 泰清, 高村 仁一1979 年 43 巻 4 号 p. 348-357
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーIn connection with the mechanism of transition from stage I to II in the work-hardening of fcc crystals, which was proposed in the previous paper, the effect of grip constraints under the uniaxial tension on the formation of ‘bend-gliding’ and the related activation of secondary slip is discussed on the basis of stress analyses. The stress analyses have been made for a rod single crystal by using the infinitesimal bending theory and the deformation gradient(strain tensor). The main results are in the following :
(1) Two stress components are important for the grip constraint, i.e., bending stress σzz and shear stress σzy, where axes z and y are the specimen axis and the projection of slip direction to the cross section, respectively. (2) The bending stress σzz acts as a force to build up ‘bend-gliding’, and the shear stress σzy contributes to the activation of secondary slip. The shear stress σzy has been resolved into twelve slip systems, whose orientation dependence is shown in relation to that of Schmid factor. (3) Stresses equivalent to the grip-constraint stresses σzz and σzy can also be observed locally in a specimen, where the bend-gliding regions are formed here and there in early stage I because of the inhomogeneous operation of primary main slip. Such formation of bend-gliding regions was proved previously by the precise X-ray analysis and also by the finite-element stress analysis. (4) The stabilization process of a bend-gliding region to form a kink band is discussed in connection with the transition from stage I to II and also with the activation of primary coplanar slip. It is also suggested that the local shear stress σzy Plays an important role on the formation of a band of secondary slip.抄録全体を表示PDF形式でダウンロード (985K) -
青木 清, 和泉 修1979 年 43 巻 4 号 p. 358-359
発行日: 1979年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (202K)
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