材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
30 巻 , 332 号
選択された号の論文の16件中1~16を表示しています
  • 土山 友博, 藤田 利夫
    1981 年 30 巻 332 号 p. 427-433
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The effect of N content on creep rupture properties, mainly creep rupture ductility, of 12% Cr heat resisting steels was studied. The creep rupture strength became higher with increasing N content below the temperature of 600°C. But, the increase in N content led to the decrease in creep rupture strength above the temperature of 650°C. The creep rupture ductility decreased with increasing N content and creep rupture time, and it was much more remarkable for reduction of area than for rupture elongation.
    To clarify the cause that creep rupture ductility decreased with increasing N content and creep rupture time, the multilinear regression analysis was carried out. As the result, it was found that the amount of precipitates and the strength level of matrix affected the decrease in creep rupture ductility.
  • 後藤 徹, 佐近 淑郎
    1981 年 30 巻 332 号 p. 434-440
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Creep rupture tests were carried out on the specimens obtained from 12% Cr-Mo-W-V steel machine parts after long-term service. Then a method to estimate the residual rupture life of the machine parts from the rupture data was proposed.
    The results obtained are summarized as follows:
    (1) The test results at higher rupture stresses tended to show underestimated residual lives when the life fraction rule was used for the evaluation of creep damage.
    (2) The residual life of 12% Cr-Mo-W-V steel should be evaluated by considering the effect of material deterioration in addition to the creep damage given by the life fraction rule.
    (3) The material deterioration was quantitatively expressed in terms of the reduction of high-temperature tensile strength. On the assumption that the rupture strength was proportional to the tensile strength, the authors proposed a method how to evaluate the reduction in creep stress caused by the material deterioration.
    (4) The experimental results obtained from the long-term used machine parts were well explained by the combination of the life fraction rule and the material deterioration. The estimated rupture life obtained after correction of the damage caused by long-term service coincided well with the rupture data of the material before service.
  • 田村 学, 井原 義人, 谷村 昌幸
    1981 年 30 巻 332 号 p. 441-446
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    For the estimation of remaining life time of structural parts used at high temperatures a lot of systematic data should be collected on the specimens which were subjected the simulated history. Types 304H, 316H, 321H and 347H stainless steels and 18 Cr 10 NiTiNb stainless steel were crept for up to 60000hr at 600-700°C and were also aged for up to 25000hr at 600-800°C. The cavity density was determined in the creep-ruptured specimens. The change of optical micro-structure due to aging was examined and X-ray analyses of extracted residues were performed. The change of mechanical properties, particularly creep rupture properties, were also investigated.
    The results show that the creep strain of structural parts after a long service period is usually less than 1%, and that the creep strain of a few per cent is necessary for detecting creep cavities. In addition to well-known M23C6 carbide, sigma phase and M7C3 were newly found in Type 304H aged at 700°C for 25000hr. The creep rupture strength of Types 321H and 347H steels decreased clearly after long time aging. However, the creep rupture strength of these steels for any aging condition was not less than 80% of that of the as-solution treated. When the creep strain and cavitation of materials in service are negligible, its remaining life time is considered to be predictable from synthetic analysis of various properties, i.e. creep rupture, impact value, hardness, etc., as refering the data on aged materials under no load condition.
  • 田中 千秋, 大場 敏夫
    1981 年 30 巻 332 号 p. 447-453
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Empirical equations to describe reloading stress relaxation data were proposed in the previous papers8)9) on both ferritic and martensitic bolting steels. In this paper, application of the equations proposed was discussed to austenitic 19Cr-9Ni-1.4Mo-1.4W-Nb bolting steel which shows a peculiar stress relaxation behavior caused by structural changes during test10)11).
    Reloading stress relaxation tests on the steel were carried out at 650°C and at the initial stress (σ0) of 29.3kgf/mm2 which corresponds to the value of stress for the total strain of 0.20 percent. Repeated loadings were undertaken up to forty-five times at specific reloading time intervals (ti=24, 72, 240 and 720 hours), and at specific residual stresses (σrj=0.9σ0, 0.8σ0, 0.7σ0, 0.6σ0, 0.5σ0, 0.46σ0kgf/mm2).
    It was confirmed that the reloading stress relaxation curves of the present steel could not be represented by the creep constitutive equations as mentioned in the previous papers. The reloading stress relaxation data obtained for the steel showed a decrease in relaxation strength with increasing loading cycles except for the earlier numbers of loadings. Moreover, the specimens with specific residual stresses lower than 0.7σ0 resulted in failure. Their fracture mode was of intergranular type caused by linkage of grain boundary cavities.
    From examinations of accumulated plastic strain data, it was confirmed that slightly modified equations to describe the reloading stress relaxation data were applicable to the present steel. The modified equation for specific reloading time intervals data is
    log(σ0ri)=a0+a1logti+a2(logti)2+a3logN
    For specific residual stresses data, the expression is the same as the previous one:
    logtj=b0+b1log(σ0rj)+b2{log(σ0rj)}2+b3logN
    where σri is the residual stress, tj is the testing time, N is the number of loadings, and a0, a1, a2, a3, b0, b1, b2, b3 are constants.
  • 金澤 健二, 山口 弘二, 佐藤 守夫, 鈴木 直之, 金尾 正雄
    1981 年 30 巻 332 号 p. 454-460
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to obtain basic data for high-temperature, high-cycle fatigue properties of S45C(0.45C) and SCM435 (0.35C, 1Cr, 0.15Mo) steels, rotating bending fatigue tests were carried out up to 108 cycles on smooth and two kinds of notch specimens at room temperature, 200, 300, and 500°C with a frequency of 125Hz.
    The fatigue strength at 108 cycles and the S-N curves up to 108 cycles were found to change depending upon test temperature and stress concentration factor. The temperature and material dependences of fatigue strength of the smooth specimen were explained qualitatively by the blue brittleness phenomenon of the materials used.
    Cracks were observed on the cross section of specimens endured 108 cycles sometimes depending on the test condition. The temperature dependence of the change in fatigue strength due to the variation of stress concentration factor corresponded to the existence of such cracks. The notch root curvature for branch point at 400∼500°C was larger than that at room temperature to 300°C. It is considered that oxidation film formed at the surface of crack plays an important role in delaying for crack to propagate.
  • 1981 年 30 巻 332 号 p. 461-466
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 花田 禎一, 江島 啓文, 曽我 直弘
    1981 年 30 巻 332 号 p. 467-470
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The effects of minor components added to the base glass of 90GeO2·10Na2S (mole %) on darkening and fading characteristics of the glass during and after U.V. irradiation were investigated. Ce2O3, Eu2O3, ZrO2, Mn2O3, V2O5, PbO, TiO2, FeO and Cu2O were used as the additive agents. Among these additive agents, Ce2O3, Eu2O3 and ZrO2 were found to be effective on the acceleration of the darkening and fading characteristics of the base glass. In particular, Eu2O3 was the most effective. Furthermore, it was found that the ability of the additive agent to enhance the characteristics of the glass depended upon the kind and the concentration of the additive agent.
  • 岡崎 章三, 中村 宏, 岡田 満, 鈴木 恵
    1981 年 30 巻 332 号 p. 471-477
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to estimate the fatigue lives of various machine parts, it is important to get the S-N diagrams of steels, particularly those of various casehardened steels which are used often for the principle elements of these machine parts, for example gears, axles, and so on. In this study, a general method to get the S-N diagrams graphically from the hardness and residual stress distributions was proposed. It was clarified that the proposed method was appropriated from the results of fatigue tests on S15C, S45C and SCM435 specimens with tufftriding treatment.
  • 加藤 章
    1981 年 30 巻 332 号 p. 478-482
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    When a copper plated specimen is subjected to cyclic stress, grown grains appear in the plating zone. In this investigation, the relation between the density of grown grains and the stress amplitude has been examined. The result showed that the relation between the grown grain density r and the stress amplitude τ was expressible by the equation, τ=A+B·ln(1/r-1), where A and B are constants determined by the number of stress cycles and the plating solution. Thus, when the coefficients A and B are obtained in advance for the plating solution to be used, the stress at the measuring portion can be found from the above equation by measuring the density of grown grains at the portion. By using the above method, the stress concentration factor of the shaft with a semi-circular groove in torsion was measured. It was found that this method was an accurate way for stress analysis.
  • 田中 道七, 酒井 達雄, 岡田 憲司
    1981 年 30 巻 332 号 p. 483-489
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Rotating bending fatigue tests were carried out on SUS 304 stainless steel specimens with a number of corrosion pits on their surfaces to investigate statistically the propagation behaviors of surface cracks prior to their mutual coalescence. The important findings in the present study are summarized as follows.
    It was observed that the fatigue cracks were initiated from the pits having the diameters of more than about 50μm among a number of pits whose diameters were distributed from a few micrometer to about 0.1mm.
    It was also found that the crack growth rate dl/dN was distributed inside a band of certain width on a log-log paper when plotted against σ√πl, and a regression line was drawn as a representative relation between dl/dN and σ√πl. By combining this relation with the experimentally found distribution of N0, that is the number of cycles until crack grows to a length of l0, the distributions of the crack length at a given cycle ratio and of the number of cycles at a given crack length were theoretically derived. The results were in good agreement with the experimental trends.
  • 公江 茂樹, 中村 宏, 恒成 利康
    1981 年 30 巻 332 号 p. 490-495
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The influence of transverse stress at the notch root on the fatigue crack initiation life of side notched plates was discussed. Axial, transverse and equivalent stresses at the notch root of the side notched large plates were calculated using the strains measured with strain gauges. Further the same plates were fatigue-tested to relate the fatigue crack initiation life with stress amplitudes at the notch root.
    The results obtained are as follows:
    (1) Equivalent stress at the edge was slightly smaller than that at the notch root. This corresponded to the test result that fatigue crack did not initiate at the edge.
    (2) The fatigue crack initiation life coincided with that calculated by using σ-ε relation, S-N relation of the material and the relation among shape factor, plastic stress concentration factor and strain concentration factor.
  • 北川 孟, 丸山 英雄, 市川 文彦
    1981 年 30 巻 332 号 p. 496-502
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Some of the important mechanical properties of a steel sheet or plate, such as the Lankford value, r, and the separation index, SI, show texture dependency. In this study, these two properties, r and SI, were related to the propagation-velocity of elastic waves in steel, which varies with its texture. SI is defined as the total separation length devided by the fractured surface area at the time when fracture occurs on a specimen in the impact test. Elastic waves were propagated in two modes: perpendicular or parallel to its surface.
    The main results obtained are as follows:
    (1) For elastic waves propagating perpendicularly to its surface, it was found that the square of the propagation-velocity of longitudinal waves, vL2, was proportional to the averaged Lankford value, r, but decreased linearly with increasing SI. The theoretical considerations made in this study revealed that vL decreased monotonously with an increase in <100> axis-density parallel to the normal direction of the specimen, but increased monotonously with an increase in <111> axis-density parallel to the normal direction. The experimental results reported so far show that the <100> axis-density parallel to the normal direction is proportional to SI, and the <111> axis-density parallel to the normal direction is proportional to r. Thus, the combination of these theoretical and experimental results yield the behaviour obtained in the present experiments.
    (2) For elastic waves propagating in parallel with its surface, it was found that the square of the propagation-velocity of surface waves, vS2, was proportional to the Lankford value in the direction parallel to the wave-propagation. Lamb waves may also be used for this kind of measurement because of its similarity to surface waves.
    Since the propagation-velocity of elastic waves can be measured continuously while steel is being produced, the on-line evaluation of some mechanical properties such as the Lankford value or the separation index of steel seems possible.
  • 沖津 昭慶, 今泉 敏幸
    1981 年 30 巻 332 号 p. 503-509
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    In the past, several investigations have been made on the vibrational characteristics of finite length sandwich beams with a viscoelastic core between two elastic layers. Since the viscoelastic core is not usually joined perfectly to the elastic layers with adhesive and is not thick enough in comparison with adhesive layers, it is considered that the adhesive layers have a great effect on vibrational characteristics of the sandwich beams. Nevertheless the effect of adhesive bonding has been neglected in the existing theories1)3)∼5).
    The purpose of this paper is to elucidate the effect of adhesive bonding on damping characteristics of the sandwich beams. The sandwich beams were assumed to consist of two elastic layers, one viscoelastic layer and two adhesive layers in the present analysis. Moreover, properties of the adhesive were assumed to vary from the original depending on the condition of adhesive bonding. Many specimens were made and tested to verify the theoretical solutions. The experimental results agreed well with the theoretical ones and showed that the effect of adhesive bonding could not be neglected. Thus, the effect of adhesive bonding should be taken into account when the sandwich beams are designed. The degree of the effect of adhesive bonding was qualitatively expressed by using the non-dimentional parameter A*.
  • 新保 正樹, 越智 光一, 大山 紀隆
    1981 年 30 巻 332 号 p. 510-516
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Frictional behaviors of the bisphenol type epoxide resins which were cured with aliphatic α, ω-diamines and have network chains in different concentrations were followed by monitoring the change of frictional coefficient in the glassy, transition and rubbery regions of the system.
    In the glassy region, a constant value of frictional coefficient was obtained in spite of the variation in contact pressure. A good correlation was observed between the frictional coefficient and the concentration of network chains or modulus of the cured system.
    In the transition region, the maximum value of frictional coefficient was observed at the glass transition temperature. A good correlation was observed between the maximum values of frictional coefficient and the damping of cured resins.
    In the rubbery region, a constant value of frictional coefficient was observed in spite of variation in contact pressure. A good correlation was observed between the frictional coefficient and the concentration of network chains.
  • 川本 〓万, 渡嘉敷 直彦, 石塚 与志雄
    1981 年 30 巻 332 号 p. 517-523
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    In planning construction of underground structures, it is important to carry out stability analysis of rock masses which requires precise properties of fractured rocks.
    In this paper, an experimental study of rock-like materials by uniaxial compression tests using a new type of high stiff loading machine is presented. Four kinds of rocks were selected, namely, Oya-stone (green tuff), Kobe-tuff, cement mortar and marble stone. Three different loading procedures were employed, i. e., static loading, incrementally cyclic loading and cyclic loading in the post-failure region (see Fig. 3).
    The machine used in the experiments has high stiffness of about 310ton/mm, and is capable of controlling either deformation or load of the specimen by mechanical action of the wedges under steel blocks installed in parallel with a specimen. This loading machine is very practical and efficient to obtain a complete stress-strain curve of geologic materials.
    The main results obtained are summarized as follows:
    (1) The stress-strain curves obtained could be divided into four characteristic regions in the progress of fracturing, namely, the intact, crack, fracture, and flow regions. The strains corresponding to each region were related to the strength, or the fablic of materials.
    (2) Tests of incrementally cyclic loading showed that the envelop of unloading and reloading curve was coincident with the statical loading curve.
    (3) The relationship between the plastic strain and the total strain on incrementally cyclic loading was representable by Weibull's probability.
    (4) Fatigue life under cyclic loading in post-failure region was influenced significantly by crypto-damage due to the initial loading and the applied stress level.
  • 中島 浩衛, 菊間 敏夫, 松本 紘美
    1981 年 30 巻 332 号 p. 524-530
    発行日: 1981/05/15
    公開日: 2009/06/03
    ジャーナル フリー
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