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Volume 65, Issue 7
Displaying 1-17 of 17 articles from this issue
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Koichi Yagi, Atsushi Suzuki, Ryoichi Yamamoto2001 Volume 65 Issue 7 Pages 547
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSDownload PDF (141K) -
Narito Shibaike2001 Volume 65 Issue 7 Pages 548-556
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSA rationalized methodology focusing on environmentally conscious materials selection for product design is described. This is a well-tailored application of the famous methodology for materials selection in mechanical design built by M. F. Ashby. A new value, environmental performance, is defined as the ‘product performance per its environmental impact’ in order to make a productive method, and is introduced into practical design process as well as a conventional value, cost performance. A case study on materials selection for TV’s front cabinet is presented to show the method’s effectiveness. According to the study magnesium alloys can be used for the component instead of the conventional material, polystyrene-fireproof in compound aspects of performance, cost and impact. An environmental impacts database of engineering materials to support the methodology is quite important and being created. A further approach on the development of a tool using a trial database for the efficient evaluation of materials is also presented. This software has a couple of benefits for average designers such as automatically creating of the performance indices and value functions, and its menu system to designate the design and value conditions is really easy and swift to use even if not having professional knowledge. The case study on head arms of hard disk drives makes it clear that the tool is valuable to create green products, particularly in the early stage of design process.View full abstractDownload PDF (1131K) -
Nobuhiko Takamatsu, Hiroshi Ohashi2001 Volume 65 Issue 7 Pages 557-563
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThe “Establishment of a Sustainable Society Based on Material Recycle” can be regarded as an issue urging a fundamental change in the values and social systems of the modern society and a challenge demanding a reform of the industrial structure from the conventional systems of individual optimization. This paper reports our views on LCA (Life Cycles Assessment) issues and on material selection, taking LCA of automobiles as an example, and challenges of Japanese steel industry on them.
The LCA study on automobiles makes us aware of the significance of not only data itself but also the development of Life Cycle Aspect which tries to evaluate Life Cycle Cost and Function, etc.View full abstractDownload PDF (589K) -
Kohmei Halada, Kiyoshi Ijima, Nozomu Katagiri, Takahiko Okura2001 Volume 65 Issue 7 Pages 564-570
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSOre-TMRs, which are the total amount of overburden and rock to obtain metal ore, were estimated as a fundamental data to estimate the value of TMR(Total Materials Requirement) of metals. Ore-TMR of coal, iron, copper, zinc and tin are estimated 12.5, 5.1, 304, 34 and 95 representatively by statistic method based on hearing and investigation of practical mining sites. An approximation from the quality of crude ore and further approximation from the concentration of the metal in the crust were also proposed as
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (437K) -
Kiyoshi Ijima, Kohmei Halada2001 Volume 65 Issue 7 Pages 571-580
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSCO2, SOx, NOx emissions form non ferrous metal processing were estimated by using economical statistical yearbook of the year 1999. The subjected processes were ore-mining, Cu-smelting, Cu-electrolysis, Pb-smelting, Pb-electrolysis, Zn-electrolysis, distilled Zn, secondary Al, Al sheet rolling, wrought Cu, electric wire production, and optical fiber production. These inventory data were compared with the data of 1989. The “Cradle to Gate” emissions were also calculated. The greater part of emissions were put on the foreign countries.View full abstractDownload PDF (582K) -
Tatsuhiko Aizawa, Tachai Luangvaranunt, Katsuyoshi Kondoh2001 Volume 65 Issue 7 Pages 581-588
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSAll recyclable materials such as the used mechanical parts or home-housing members are melt, solidified and wrought to down-graded materials in the conventional recycling. Solid-state recycling is a promising approach to accept the mechanical chips and wastes generated in production as input and to yield the upgraded alloys and compounds as output. This new approach requires innovative processing to fabricate the targeting products via in-process refinement and control of microstructure as needed from the product design. In the present paper, the bulk mechanical alloying process is used for solid state recycling to make microstructure refinement from the mechanical chips to a dense powder compact. In experiment, Al-Si system is employed as a typical material for automotive parts, which must satisfy the requirement of fine Si-particulate size in the final product. Together with refinement experiment, the plastic power history imposed to a sample is continuously monitored during bulk mechanical alloying to be compared with the total energy consumption in the commercial production line from atomizing process to preliminary sintering. The number of cycles required to attain the largest Si-size demand of 7 μm was only 100, so that the energy consumption could be reduced from that needed by the conventional powder metallurgy process working in industry. The present method is robust in processing even when varying the morphology and Si concentration in the input materials.View full abstractDownload PDF (1719K) -
Nobuhiko Narita, Masayuki Sagisaka, Atsushi Inaba2001 Volume 65 Issue 7 Pages 589-595
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThe reduction effects of CO2 emission from typical steel products by the reduction agent injection into blast furnace were analyzed by Life Cycle Assessment methodology, using the statiscal data.
As the results, the reduction effects by pulverized coal injection and waste plastic injection were estimated to be 0.07 kg and 0.16 kg-CO2 at the point of 0.1 kg/kg-HM of injection, respectively. As the coke is replaced with pulverized coal on the equivalent in carbon content, the CO2 emission from the coke manufacturing is reduced. And the reduction effect of CO2 emission by waste plastic injection is higher than that by pulverized coal injection, because the replacement ratio of coke with waste plastics is higher. The injection ratio of waste plastics would not be raised to the same ratio as the pulverized coal in the viewpoint of the material balance of waste plastics.View full abstractDownload PDF (532K) -
Michinobu Furukawa, Toshihiko Koyama, Yoshihiro Muneta, Yuichi Ooki2001 Volume 65 Issue 7 Pages 596-603
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSLCA (Life Cycle Assessment) has been conducted on residential gas appliances designed based on the eco-design guide that city gas suppliers planned, for certifying validity and clarifying problems of it. In other words, life cycle inventories of these gas appliances were generated, and Life Cycle Impact Assessment (LCIA) was carried out. Five environmental impact categories were considered: “Resources Consumption”, “Global Warming”, “Acidification”, “Energy Consumption”, and “Solid Waste”. The following results were obtained. Components of residential gas appliances are mostly iron and nonferrous metals. The residential gas appliances designed to be light give lower environmental loads at the production stage than general gas appliances, but occasionally the environmental loads are increased. This suggests there is the trade-off relation between the designing for lightness and the environmental loads depending on the material. It is necessary to develop the optimizing techniques to minimize environment loads when the material is selected. It is necessary to develop a new LCA methodology by which the change of the inventory as time passes is considered with the product that has large environmental loads at the using stage.View full abstractDownload PDF (553K) -
Hiroyuki Katayama, Keijiro Masui, Tomohiko Sakao, Toshihiro Kitamura, ...2001 Volume 65 Issue 7 Pages 604-606
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSIn order to expand the practical use of the developed ecomaterials in the assembled products and to promote the development of the desired ecomaterials, an information common tool is proposed. This tool is composed from two databases: one is on the environment conscious targets and the means. The other is on the properties of materials. It is expected to be useful for design engineers of the assembled products, and for the material engineers.View full abstractDownload PDF (229K) -
Fuxing Yin, Susumu Takamori, Yoshiaki Ohsawa, Akira Sato, Kohji Kawaha ...2001 Volume 65 Issue 7 Pages 607-613
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSControl 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.View full abstractDownload PDF (1089K) -
Shigeo Yamamoto, Susumu Takamori, Yoshiaki Osawa, Akira Sato2001 Volume 65 Issue 7 Pages 614-620
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSAn alternate material of free cutting steel without lead should be developed soon to facilitate steel recycling. The development of a high-strength free-cutting steel is also desired for weight reduction and performance of machine parts. This experiment was carried out to develop free-cutting steel without lead.
In this experiment, we deoxidized the steel by titanium. then quenched and tempered it to a Vickers hardness of 400. The normally used aluminum deoxidized steel was chosen as a comparison material. The tool wear width (VB) after cutting the titanium deoxidized steel was remarkably decreased due to the complex oxide that contains titanium. Complex oxide adhered to and piled up on the tool plane while cutting. The piled-up sediment is called “Belag” and is able to protect the tool plane from the fretting of the chips.View full abstractDownload PDF (1328K) -
Yasumasa Chino, Ryuji Kishihara, Koji Shimojima, Yasuo Yamada, Cui&rsq ...2001 Volume 65 Issue 7 Pages 621-626
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSWe have proposed the “Solid Recycling Process” as a new recycling process for magnesium scraps. In the new process, the recycled materials can be fabricated without melting of scraps, by extruding the scraps. We have investigated corrosion and mechanical properties of the AZ91D magnesium alloy fabricated by this process and clarified the validity of this process. Chemical compositions of the recycled material were in agreement with those of the Japanese Industrial Standard of AZ91D and the contamination levels of Fe, Ni, Cu and Si were low, though Si particles were observed by TEM observation. Mass loss of the recycled material after 72 hour in 3 mass%NaCl solution was about 1.5×10−2 kg/m2 which was comparable with that of a virgin ingot. The recycled material showed high strength and larger elongation than a virgin ingot. The feature of the solid recycling process is improvement of mechanical properties by recycling. The improvement of mechanical properties is attributed to grain refinement by hot extrusion.View full abstractDownload PDF (814K) -
Takahiko Terada, Hiroshi Onishi, Tetsuji Kawakami2001 Volume 65 Issue 7 Pages 627-634
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSA variety of composite materials are being applied to a wide range of products for recent years. Composite materials, however, are often difficult to separate into their component materials for collection and reuse. We found a new solvent-decomposition method by which an epoxy resin (which is one kind of thermosetting resin) can be easily decomposed. Applying this recycling method, magnetic powder was separated from bonded magnets with minimal loss of quality. Using this method, the plastic matrix can be chemically decomposed without degrading the embedded metallic materials. It was found that this process could be widely utilized for recycling composite materials containing various metals and composite materials could be Environmentally Conscious Materials.View full abstractDownload PDF (714K) -
Atsushi Yumoto, Fujio Hiroki, Ichiro Shiota, Naotake Niwa2001 Volume 65 Issue 7 Pages 635-643
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThis paper presents the development of supersonic free jet PVD as a new coating method for structural material to overcome technical problems contained in other coating methods. This PVD method consists of evaporation in gas atmosphere and deposition in vacuum, i.e., ultra-fine particles are formed, carried and deposited to form film in a space of connected chambers, where ultra-fine particles formed by the evaporation of material in an evaporation chamber with helium gas atmosphere are carried to a substrate with gas flow generated by the pressure difference between the evaporation chamber and a vacuumed deposition chamber and deposited with high velocity to form film.
This study aims to form the metallic films of titanium and aluminum with the method and to elucidate the effects of control parameters for the development of the method. The velocity of ultra-fine particles should be an important parameter for the film formation. In order to increase carrier gas velocity to increase particle velocity, we designed a nozzle on the assumption of one-dimensional isentropic flow to attain the gas velocity of Mach 3.6 at the outlet of the nozzle.
The results obtained are as follows: (1) Reduction of coarse particles by suppressing the stagnancy and secondary agglomeration of particles is necessary for producing metallic films of titanium and aluminum. (2) Growth rate of film increases in proportion to electric power to evaporate source metal. (3) To heat a nozzle is effective for the formation of film without voids. (4) No cracks were formed by indenting the diamond indenter of micro Vickers hardness tester at the interface between substrate and coated film with the force of 4.9 N, which indicates strong adhesion between them.View full abstractDownload PDF (2130K) -
Toshihiko Koseki, [in Japanese]2001 Volume 65 Issue 7 Pages 644-651
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSEquiaxed solidification of steel was investigated with emphasis on the nucleation on titanium nitride (TiN). Ferritic stainless steels bearing different amounts of titanium and nitrogen were remelted using a gas-tungsten-arc welding, and equiaxed grain formation was examined in the as-solidified welds. It was found that the precipitation of TiN in the melts prior to solidification is a prerequisite for columnar-to-equiaxed transition (CET) to occur. The most distinct CET and the largest number density of equiaxed grains are obtained when the TiN precipitation initiates approximately 30 K above the liquidus temperature of the melt. When the TiN precipitation is at even higher temperatures, on the other hand, the CET is adversely affected even though the amount of TiN formed prior to solidification increases. This is probably due to a decrease in the number of effective TiN particles since higher precipitation temperature increases time and space for TiN particles to coarsen, ripen and float out before they reach the solidification front. Liquid-tin quenching was applied during the solidification to directly observe the solidification front. Equiaxed grain formation on TiN is clearly identified in the melt within 200 to 300 μm ahead of the solidification front. The solutal undercooling ahead of the front is also a prerequisite for the equiaxed grain formation, but the number of TiN particles supplied to this region as a nucleating agent should be more dominant for CET and for higher density of equiaxed grains.View full abstractDownload PDF (1349K) -
Hideaki Kato, Masaaki Kato, Yoichi Nishino, Uichiro Mizutani, Shigeru ...2001 Volume 65 Issue 7 Pages 652-656
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSWe report on the temperature dependence of electrical resistivity, Seebeck coefficient and Hall coefficient of the Fe2VAl1−ySiy alloys with Si compositions y=0−0.20. While the Heusler-type Fe2VAl (y=0) exhibits a semiconductor-like resistivity behavior, a slight substitution of Si for Al causes a sharp decrease in the low temperature resistivity and a large enhancement in the Seebeck coefficient. Substantial enhancements for the Seebeck coefficient are in reasonable accord with changes in the Hall coefficient and can be explained on the basis of the electronic structure, where the Fermi level shifts slightly from the center of the pseudogap due to the substitution of Si. In particular, the Si substitution of y=0.10 leads to a large power factor of 5.4×10−3 W/m K2 at room temperature, which is comparable to that of conventional thermoelectric materials.View full abstractDownload PDF (315K) -
2001 Volume 65 Issue 7 Pages 657
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSPlease see Errata PDF Wrong:Fig. 4 Right:Fig. 4View full abstractDownload PDF (137K)
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