著者
辛島 恵美子
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.66, no.12, pp.1236-1245, 2002 (Released:2008-04-24)
参考文献数
27

The Shinkansen Line has experienced no serious car-accidents since its operation start in 1964. Why has the Shinkansen Line been able to keep such a good safety performance? This paper intends to clarify the background and the reasons why those miracles became possible—when, what kinds of risks and what kinds of actions the staff of the Japanese National Railways took in, who participated in the development of the Tokaido Shinkansen railway-axles in 1950s∼1960s as a designer, an investigator, a maintenance engineer, an inspector, or a top executive in technology. I discovered all the staff had been dedicated to their duties and their actions were prudent enough in general. As a result their behaviors have reduced the riskiness of their works objectively. But the most of the staff were not so much sensitive to risk itself as a few technical top executives of JNR. For example when the inspectors first found unexpected micro cracks on the 20% running axles in 1965, the top executives adapted a new management system in 1966 based on those inspections, which contained a systematic long-range R&D plan of high-quality railway-axles as well as an effective risk management for micro cracks.
著者
梅川 莊吉
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.18, no.8, pp.449-452, 1954 (Released:2008-04-04)
参考文献数
6
被引用文献数
1

Young’s modulus and its change accompanied by heat-treatment and by cold-working in gold-silver and gold-copper alloys has been measured by lateral vibration method of a cantilever under small amount of stress. The composition dependence of Young’s modulus is monotonous in both alloy systems. Young’s modulus of Cu3Au increases and of CuAu decreases the superlattice formation. The effect of cold work on Young’s modulus is similar for some gold-silver alloys, but it differs considerably with some gold-copper alloys.
著者
杉岡 奈穂子 北田 正弘 西嶋 雅彦
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.77, no.5, pp.185-191, 2013 (Released:2013-05-01)
参考文献数
15
被引用文献数
2

The metallurgical microstructure and mechanical properties of the spear blade manufactured in the Edo period have been investigated. The purpose of this work is to obtain metallographic data of the spear blade, and to clarify the manufacturing technique of the spear blade. The specimen examined was estimated to have been made from the end of the Muromachi period to the Edo period and has the signature of Shinano-no-Kami Minamoto Takamichi. The spear is 31 cm in length and 10.7 mm in maximum width. The metallurgical microstructure and nonmetallic inclusions of the spear blade are observed using an optical microscope. The carbon concentration is determined by chemical analysis. To evaluate the hardness, micro Vickers hardness (Hmv) is used. The microstructure is observed using an optical microscope and a scanning electron microscope (SEM). The concentration of nonmetallic inclusions is obtained by electron dispersive X-ray analysis (EDS).    A cross-sectional image of the spear after chemical etching shows a metal flow pattern formed by deformation, possibly created by hammering. The striped structure of layers of two types of steel containing different carbon contents stacked on top of each other was observed. The bright areas after etching corresponded to the edges and ridges of the spear, which were cooled rapidly, forming the martensite structure. The other dark areas consist of pearlite and α-Fe (ferrite) grains. Optical micrographs of near-edge areas contain pearlite and martensite grains, and core areas contain pearlite and α-Fe grains. The nonmetallic inclusions in the core steel consist of a few metal oxide particles and a glass matrix. There are Fe-Ti oxide grains in the glass matrix, and an unknown oxide particle adhering on the Fe-Ti oxide grain surface was also observed.
著者
原田 幸明 島田 正典 井島 清
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.71, no.10, pp.831-839, 2007 (Released:2007-10-01)
参考文献数
8
被引用文献数
11 6

Forecasting are made regarding the consumption up to 2050 of following metals: Fe, Al, Cu, Mn, Zn, Cr, Pb, Ni, Si, Sn, rare earths, Mo, Li, Sb, W, Ag, Co, In, Au, Ga, Pt and Pd. The forecasts are based on the liniar decoupling model of the relation between per capita metal consumption and per capita GDP. The models of each metal are applied to the economic development model of BRICs and G6 countries. According these forecasts, the overall consumption of metals in 2050 will be five times greater than the current levels, and demand for metals, such as Au, Ag, Cu, Ni, Sn, Zn, Pb, and Sb, is expected to be several times greater than the amount of their respective reserves. Demand for iron and platinum, which is considered to be optimistic about the resource exhaustion, will also exceed the current reserves. Urgent measures are needed to find alternatives from common resources and to shift into materials circulation society.
著者
釘屋 奈都子 永田 和宏 北田 正弘
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.78, no.4, pp.149-158, 2014 (Released:2014-04-01)
参考文献数
14
被引用文献数
1

The manufacturing technique of steel chains used for four Japanese armatures from the end of Muromachi to the Edo period has been investigated. The chains used in Kusazuri (tasset) and two types of Kote (guntlet) were composed of steel rings in round and oval shapes while those used in Kusarikatabira (chainmail) was only round. As for the former ones, round rings were connected by oval rings. The diameter of steel wire of rings was about 1 mm. The steel wire was produced from steel plate with the carbon content of 0.11 to 0.40 mass%. Steel was forge-and-welded twice to make in plate and was cut in a bar. The steel bar was drawn into standardized wires by die with the draft percentage of about 25% and annealed. Drawing of standardized wire followed by annealing was repeated several times to make a wire for armatures. The crystal grains in wires were elongated in axial direction and the aspect ratio of grain in oval rings was larger than that in round rings. A wire was rolled around a stick and cut by chisel to make rings.
著者
桐野 文良 大野 直志 田口 智子 根津 暁充 横山 亮一
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
2019

<p>The production processes of old Japanese coins, <i>Genbun-koban</i>, <i>Akita-ginban</i> and <i>Morioka-ginban</i>, were studied. These coins were manufactured by a forging method in the <i>Edo</i>-era. <i>Genbun-koban</i>, manufactured at a gold mint of the <i>Tokugawa</i> shogunate called <i>Kinza</i>, in 1736, is made of Au-Ag alloy and its surface is not flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. The <i>Iroage</i> method was used to color the coin; it is a thermal treatment, resulting in lows the residual stress is smaller at flat area. <i>Akita-ginban</i>, manufactured in the <i>Akita</i> domain in 1863 is made of pure Ag and its surface is also not flat. There is no residual stress in this coin. This result shows that the thermal treatment of this coin was carried out after processing. <i>Morioka-ginban</i>, manufactured in the <i>Morioka</i> domain in 1868, is made of pure Ag, and its surface is flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. This result shows that the thermal treatment was not carried out after processing. These coins manufactured in the <i>Edo-</i>era thus had different thermal treatments.</p>
著者
花田 修治 渡辺 貞夫 佐藤 敬 和泉 修
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.45, no.12, pp.1279-1284, 1981 (Released:2008-04-04)
参考文献数
30
被引用文献数
5 8

Magnetic heads made of Sendust alloy head cores (standard chemical composition: Fe-9.6 wt%Si-5.4 wt%Al) are known to have superior magnetic properties and wear resistance. The cores are usually made by mechanical working, such as slicing and grinding since the alloy is so hard and brittle that it has been believed to be difficult to make head cores by plastic deformation. In the present work, plastic deformability of the alloys was investigated by compressive tests on Sendust single crystals at temperatures between room temperature and 1173 K and various strain rates. Main results are summarized as follows.The operative slip systems are {110}〈111〉 and {112}〈111〉 depending on compressive axis. Therefore, the von Mises criterion for a polycrystalline material to deform plastically by slip within grains is satisfied, indicating that the brittleness of Sendust alloys cannot be explained by the number of independent slip modes available. At room temperature the stress-strain curve exhibits three stages in a similar manner to Fe3Al and Fe3Si with DO3 structure.Above the temperature where yield stress decreases abruptly, the steady state deformation takes place. Under the condition of the steady state deformation, the strain rate is represented by the relationship of \dotε=Bσnexp(−Q⁄kT), where n=4.6 and Q=540 kJ/mol. These results suggest that even a polycrystalline material of Sendust alloy may be deformable under the suitable conditions.
著者
松原 三徳 杉山 圭司
出版者
社団法人 日本金属学会
雑誌
日本金屬學會誌 (ISSN:00214876)
巻号頁・発行日
vol.6, no.9, pp.481-487, 1942 (Released:2008-11-13)
参考文献数
10

The effects of, concentration of nitric acid and temperature were examined on hard rolled aluminium (Purity=99.70%) by dip method corrosion test. The corrosion test was carried out in 5_??_98% HNO3 at 30_??_70° by measuring the weight loss for 10 hours, and the corrosion rate was expressed as g/m2hr. The results obtained were as follows. (1) In 98% HNO3; the resistivity is excellent up to 70° (2) In 94% HNO3; the resistivity is excellent at 30°, and even at 50_??_70° the resistivity is good. (3) in 92% HNO3; the resistivity is good at 30°. (4) In bellow 90% HNO3; the resistivity is rot good even at 30° and is minimum in. 30% HNO3. II. The effect of purity of aluminium was examined on virgin ingot (Purity=99.980, 99.74, 99.60, 99.38, 99.18 and 98.40%) by dip method corrosion test. The corrosion test was carried out in 30%, 90% HNO3 at 30° by measuring the weight loss for 10 hours, and the corrosion rate was expressed as g/m2hr. The results. obtained were as follows. (1) In cone. HNO3 the effect of purity of aluminium is very small. (2) In dil HNO3, the effect is small as far as purity of aluminium is above 9938%.
著者
星 恵理子 北田 正弘
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.67, no.7, pp.336-341, 2003 (Released:2008-04-24)
参考文献数
12
被引用文献数
4

The effects of Cu-containing pigments on degradation of Japanese paper have been investigated. A hand-coloured wood-block print of the late Edo era is used as a naturally aged specimen. To clarify the degradation mechanism, sheets of modern Japanese paper painted with powdered malachite are aged in an environment of 353.15 K(80°C), 65%RH. Pigments are examined with XRD. Degradation of the paper is examined with a three-dimensional fluorescence spectrometer. Cu content in the specimen is measured by ICP-AES and EDS. The Cu concentrations of the cross-sections of naturally aged specimen decrease with increasing depth. In addition, the Cu concentrations at the same depth of the artificially aged paper increase with aging. These results show that the Cu species diffuse from the right to the wrong side of the paper. Although the green pigment of wood-block print contains Cu species and As species, only the Cu species has been detected in the fiber of the degraded part of the paper. The degree of degradation of the accelerated sample painted with malachite becomes higher than that of the unpainted sample. Therefore Cu is the main species that participates in the degradation of paper. The fluorescence intensity of the papers painted with malachite decreased with increasing aging time. This result shows that diffused Cu ions make impurity levels in the band gap of cellulose.
著者
齋藤 繁 林 重成 成田 拓郎 加藤 泰道 大塚 元博 荒 真由美 成田 敏夫
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.83, no.10, pp.372-377, 2019-10-01 (Released:2019-09-25)
参考文献数
11

A diffusion-barrier coating layer (DBC) was formed on a Ni-22Cr-19Fe-9Mo alloy by Al-pack cementation at 1000℃ followed by heat treatment at 1100℃.The thermal cyclic oxidation behavior of the DBC system was then investigated. The thermal cycle oxidation tests were conducted at 1100℃ in air for 45 min, each followed by 15 min at room temperature. Electron probe micro-analysis (EPMA) was performed to determine the microstructure and concentration profile of each element between the substrate and the coating layer.The DBC system showed good thermal cycle oxidation property. The layer structure between the substrate and the coating layer after thermal oxidation cycling is discussed with respect to the composition paths plotted in the Ni–Cr–Fe and Ni–Cr–Al phase diagrams. The coating layer structure after 100 cycles of 45 min at 1100℃ consisted of the γ- and α-phases of the Ni–Cr–Fe system and the β-phase of the Ni–Cr–Al system. The coating layer structure after 400 cycles of 45 min at 1100℃ consisted of the γ-phase of the Ni–Cr–Fe system and the β-phase of the Ni–Cr–Al system. In contrast, the coating layer structure after 900 cycles of 45 min at 1100℃ consisted of the γ-phase of the Ni–Cr–Fe system.
著者
小山 敏幸
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.73, no.12, pp.891-905, 2009 (Released:2009-12-01)
参考文献数
50
被引用文献数
3 5

The phase-field method has recently been extended and utilized across many fields in materials science. Since this method can systematically incorporate the effect of coherent strain induced by lattice mismatch and applied stress as well as external electric and magnetic fields, it has been applied to many material processes including solidification, solid-state phase transformations and various types of complex microstructure changes.    In this paper, firstly the calculation method of phase-field approach is briefly explained. In particular, the basic philosophy of phase-field simulation is mentioned. Secondly, we summarize the recent calculation results of the phase-field simulation of phase transformations in Fe-based alloys and Ni (or Co)-based superalloys. Finally, the image-based calculation of materials properties is explained, where the simulated microstructure image that is the output data of phase-field simulation is employed as a boundary condition for calculating the materials property, and we show the cases of the mechanical property (stress-strain curve), magnetic property (ferromagnetic hysteresis) and electric property (ferroelectric hysteresis) as typical examples of this approach.
著者
井上 潔 島 好範
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.33, no.7, pp.755-760, 1969 (Released:2008-04-04)
参考文献数
6
被引用文献数
1

The purpose of this paper is to clarify the character of spark carburization for iron, and characteristics of the spark carburized layer which is not found in other carburizing treatments, and also to investigate the effect of superposing magnetic field and high frequency current. Through microscope and by X-ray diffraction, the following conclusions have been drawn:(1) Glycerine-25% Potassium acetate is extremely excellent for the carburizing solution, and the caburized layer of 0.2∼0.5 mm can be obtained by 5∼10 min carburization.(2) As for the structure of the carburized quenching layer, the surface shows structure including carbide, residual austenite and martensite, and moreover the inner part shows a martensite structure like fine needles. This is because the surface layer contains a large amount of carbon, and from this it can be estimated that the mechanical properties, especially wear resistance, is excellent.(3) In the carburization the high frequency current has the effect of unifying diffusion. In this case, the frequency of 350 KHz is effective. The magnetic field has the effect of increasing the carburizing ability by 50∼80% on the surface in parallel with the magnetic flux.
著者
金子 秀夫 村上 毅 池内 準
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.32, no.10, pp.982-987, 1968 (Released:2008-04-04)
参考文献数
3
被引用文献数
1 1

The process of carburization is the oldest and has been most extensively employed in industry as a method of case hardening of steels. The progress in the carburization technique, however, has not been extremely rapid. Therefore a new method with higher rate of penetration and better quality of case is extensively craved for. To find a solution of this problem, electrodischarge carburization has been conducted by the present authors to combine electrodischarge heating and the carburizing action in a special electrolyte. This is a method of case hardening of steels in a electrolyte that contains the chemicals required to produce a case comparable with one resulting from liquid carburization. This provides a convenient method of carburization, with low distortion and with considerable high rate of penetration and uniformity of control of the case.The best carburizing conditions obtained in the present study are as follows:electrolyte: ethleneglycol saturated with sodiumchlorideapplied voltage: 150 V DCcarburizing time: 1∼5 mincase depth: 0.2∼0.3 mmhardness of the case: >Hv 850
著者
桐野 文良 大野 直志 田口 智子 根津 暁充 横山 亮一
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
pp.J2018048, (Released:2019-03-01)
参考文献数
12

The production processes of old Japanese coins, Genbun-koban, Akita-ginban and Morioka-ginban, were studied. These coins were manufactured by a forging method in the Edo-era. Genbun-koban, manufactured at a gold mint of the Tokugawa shogunate called Kinza, in 1736, is made of Au-Ag alloy and its surface is not flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. The Iroage method was used to color the coin; it is a thermal treatment, resulting in lows the residual stress is smaller at flat area. Akita-ginban, manufactured in the Akita domain in 1863 is made of pure Ag and its surface is also not flat. There is no residual stress in this coin. This result shows that the thermal treatment of this coin was carried out after processing. Morioka-ginban, manufactured in the Morioka domain in 1868, is made of pure Ag, and its surface is flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. This result shows that the thermal treatment was not carried out after processing. These coins manufactured in the Edo-era thus had different thermal treatments.
著者
片山 英樹
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.78, no.11, pp.419-425, 2014 (Released:2014-11-01)
参考文献数
25
被引用文献数
1 3

Fundamentals of an electrochemical impedance measurement were reviewed. The impedance characteristics under charge transfer control and under diffusion control, and their equivalent circuits are described. Analytical method using the Nyquist plot and the Bode plot for typical impedance spectra was explained. In addition, a change in impedance behavior for CPE (constant phase element) parameter, which is often used in equivalent circuit modeling and data fitting of electrochemical impedance data, was represented. In the latter of this paper, research reports for degradation estimation of steel materials used for infrastructure using an electrochemical impedance measurement were provided. The degradation of organic coated steels, the structure of thermally sprayed coating exposed to outdoors for a long term, and the corrosion performance of reinforcing steel bars in concrete were estimated by electrochemical impedance method.
著者
宮岡 裕樹 市川 貴之 小島 由継
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.77, no.12, pp.552-558, 2013 (Released:2013-12-01)
参考文献数
26

Hydrogen is chemically absorbed into graphite by mechanical ball-milling process under H2, and its hydrogen capacity reaches to about 3.6 mass%. Noteworthy, when iron (Fe) mingles with graphite from steel balls during the milling process, the hydrogen capacity is drastically enhanced. In this work, the hydrogen absorption and desorption properties of the hydrogenated graphite with and without Fe were investigated. The hydrogen capacity of graphite including Fe was about 6 mass% (H/C), suggesting that the excess hydrogen of 2.4 mass% would originate in the Fe related phase. It is clarified by spectroscopic studies that the mingled iron formed a non-stoichiometric iron-carbon (Fe-C) phase as hydrogen absorption site. Assuming that the Fe/C ratio is 1, its hydrogen capacity is estimated to be H/(Fe-C-H)>10 mass%, which is a larger value than that of the conventional hydrogen storage materials. The hydrogen absorbed in the C-Fe phase is released at 450℃ with the transformation of the C-Fe phase to well-ordered carbides such as Fe3C. Therefore, if the C-Fe phase could be synthesized independently, it should be recognized as a promising hydrogen storage material.
著者
八木 良平 岡部 徹
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.80, no.6, pp.341-349, 2016 (Released:2016-05-25)
参考文献数
59
被引用文献数
3 5

Rhenium (Re) is used as additives in several alloys such as nickel-based superalloys for jet engine turbine blades, platinum catalysts for oil refining, and thermocouples used at ultra-high temperature, in order to improve strength and stability at high temperature. The demand of Re has been increasing with the increase in demand of the superalloys. In this article, current status such as demand and distribution of Re are reviewed, and smelting technologies for recovering Re from various ores are introduced.
著者
殷 福星 高森 晋 大澤 嘉昭 佐藤 彰 川原 浩司
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.65, no.7, pp.607-613, 2001 (Released:2008-04-24)
参考文献数
19
被引用文献数
11 16

Control of noise and vibration remains to be solved for the lowering of environmental load in all the industrial fields. It is necessary to take account of the noise and vibration problem when designing machines or structures. Therefore the development of damping materials suitable for structural parts that are easy to process and recycle, is urgently required. Mn-Cu damping alloys show the most satisfactory mechanical properties and damping capacity among the developed damping alloys. The M2052 damping alloy, which has a nominal composition of Mn-20Cu-5Ni-2Fe (at%), shows both a high damping capacity and a high strength. The damping capacity of M2052 alloy increases to a high level below a certain temperature, and the damping level also varies sensitively to the changes in vibration frequency and strain amplitude. By the peak-shift method the thermal activation energy for the {101} twin boundaries responsible for the low-temperature damping peak is calculated to be 4.88×104 J/mol. The tensile strength of the alloy is 500 MPa, accompanied with a superior workability for practical applications. It is confirmed experimentally that M2052 damping alloy is quite effective in damping the intolerable vibrations when used as structural parts.
著者
松井 光彦
出版者
公益社団法人 日本金属学会
雑誌
日本金属学会誌 (ISSN:00214876)
巻号頁・発行日
vol.64, no.5, pp.403-406, 2000 (Released:2008-04-24)
参考文献数
7

Recently sodium ionic conductors such as NASICON (Na3Zr2Si2PO12) have been used as the solid electrolyte for EMF(electromotive force) type CO2 sensors. However, it has been hard to obtain a sufficiently high quality in this type of sensor, partly due to the low humidity-resistance of NASICON and partly because of its poor initial response of EMF to CO2 pressure.For the purpose of improving the humidity-resistance and the initial response of EMF of the solid electrolyte CO2 sensors, Li2TiSiO5 is employed as the sensing material instead of NASICON. It is composed of the following electrochemical cell:(This article is not displayable. Please see full text pdf.) The electrochemical reaction is in good agreement with the Nernst equation, and reacted electron is calculated as 2.04. The sensor fabricated with Li2TiSiO5 shows good linearity when it is exposed to an atmosphere of 90% relative humidity at 60°C. The initial 90% response of EMF is steadied within 4 min. These experimental results make it possible to use the sensor in the environments.