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Volume 53, Issue 9
September
Displaying 1-14 of 14 articles from this issue
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Paper
Paper
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Yoshihiro Uragami, Yoshiaki Hata, Hiroshi Yasuoka2006 Volume 53 Issue 9 Pages 701-706
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSWe have investigated the magnetic response of superconductivity on the magnetic superconductor RuSr2Gd1.5Ce0.5Cu2O10−δ. The high-quality polycrystalline sample was synthesized with the additional excess ruthenium. Superconductivity of the sample appears below 31 K. Fundamental and higher-harmonic complex susceptibilities χn=χn'−iχn'' were measured. For all n, χn appears below 26 K. The results suggest the sample magnetizes non-linearly to magnetic fields below the temperature. The magnetization curves at low magnetic fields were obtained by substituting observed χn in Fourier series of the time-dependent magnetization. The magnetization curve below 31 K indicates a hysteresisless diamagnetism. The diamagnetism is due to the intragrain superconductivity. The magnetization curve below 26 K indicates a hysteresis loop as the mixed state in type-II superconductors simultaneously with the hysteresisless diamagnetism. The hysteresis loop is due to the intergranular superconductivity. From the hysteresis width of the magnetization curve, the intergranular-critical current density was estimated at 7.5×103A/m2 on 5 K.View full abstractDownload PDF (565K)
Special Issue:Needs of Automotive P/M Parts and, Their Net-shaping with MIM (for example) and Functionalizing
Summarization
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Akira Fujiki, Hideshi Miura2006 Volume 53 Issue 9 Pages 708
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSDownload PDF (119K)
Review
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Randall M. German, Hideshi Miura2006 Volume 53 Issue 9 Pages 709-712
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSThis article provides an assessment of the condition of the metal powder injection molding field in the USA. The analysis starts by quickly reviewing the overall condition of the US economy, looks at the condition of powder metallurgy in general and its main automotive customers.
Technology, organization and corporate changes are used to provide the status report and to assess future prospects. In spite of some well recognized advantages, significant problems are evident that hinder growth of metal powder injection molding. Positive growth in North America MIM will require significant collaboration on standards, process standardization, marketing, designer education and cost reduction. The tasks are too large for single firms, yet there is reluctance for the key industry actors to work together. As a consequence, much opportunity is evident for low-cost manufacturers.View full abstractDownload PDF (461K)
Paper
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Akira Fujiki, Yukihiro Maekawa, Kyohshi Adachi2006 Volume 53 Issue 9 Pages 713-717
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSRecently several new technologies are introduced to achieve high density of PM such as warm compaction, surface densification, high velocity compaction and so on. Die wall lubrication is one of these technologies. However, the study of quantitative analysis of die wall lubrication is very few, neither the suitable lubricant for die wall lubrication. The authors studied the die wall lubrication technologies itself comparing TRIBO type and CORONA spark type and also studied several lubricant electric charge value. Trough these studies, the new lubricant for die wall lubrication is synthesized.View full abstractDownload PDF (500K) -
Teruie Takemasu, Hideshi Miura, Yuji Nii, Takao Koide, Tatsuo Ozaki2006 Volume 53 Issue 9 Pages 718-724
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSThe purpose of this study is to optimize the finish rolling process of sintered Fe alloy gears (P/M gears) using a screw-shaped tool to improve the tooth profile accuracy and the load carrying capacity. In this article, finish rolling experiments of unmodified P/M gears using an unmodified screw-shaped tool are firstly carried out to investigate the fundamental rolling properties. The porosity in the surface layer of rolled gear teeth is reduced to the target level, but the tooth profile becomes heavily concave. Secondary, modified P/M gears with a convex tooth profile are rolled to improve the tooth profile accuracies. Gears with a good tooth profile and a good surface finish are obtained by optimizing the amount of radial feed of the tool. Finally, simultaneous rolling of tooth and fillet surface of unmodified gears using a modified screw-shaped tool are carried out. It is confirmed that the rolled tooth profile are scarcely affected by the amount of rolling stock and the tooth surface and the fillet at the root of gears are successfully consolidated in one rolling pass using this method.View full abstractDownload PDF (749K) -
Teruie Takemasu, Hideshi Miura, Tadanori Usuki, Masahito Yamamoto, Tos ...2006 Volume 53 Issue 9 Pages 725-730
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSThe final objective of this study is to establish the optimized manufacturing method of herringbone microgrooves for fluid dynamic spindles. In this article, two kinds of fundamental coining experiments of a simple indentation are carried out to create microgrooves of 5∼10μm depth. In order to compare the coining performance, two kinds of materials are used. One is an austenitic stainless steel (SUS303) of the wrought material and the other is also an austenitic stainless steel (SUS304L) of metal injection molded (MIM) material which has 5% porosity. In experiment-1, a flat head punch with three micro projections of 10μm height is pushed into a hexahedral specimen with or without the ultrasonic vibration. The groove depth of the MIM material increases in proportion to the punch load in the static indentation and its maximum value is about 80% larger than that of the wrought material. The imparting of the ultrasonic vibration is effective to increase the amount of groove depth especially for the MIM material under the lower punch load. In experiment-2, a circular punch and a circular anvil are statically pushed into a cylindrical specimen to produce 18 parallel grooves with an equal pitch in the circumferential direction. The groove profiles become almost uniform and the burr formation at tips of groove shoulder is effectively suppressed under the excessive amount of die indentation.View full abstractDownload PDF (691K) -
Koki Kanno2006 Volume 53 Issue 9 Pages 731-739
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSIt is known that one of the suitable processes to get net shape components with reasonable costs is Powder Metallurgy Process (hereafter PM process). However, dynamic properties like fatigue strength for PM components are not sufficient.
In order to improve fatigue strength of PM components, the selection of a suitable alloying system followed by optimum PM processes is one of the important things and the conditions of secondary operations like a heat treatment and a shot peening are the other important things. Resultant stress from residual stress and stress profile from loading was used to estimate the optimized secondary operations. At last 670MPa of fatigue strength has been achieved for 1.5Cr0.5Mo pre alloyed steel powder. The value is tremendously high when considered the level of PM steels some years ago.
Then the possibility to apply PM components for an actual gear in a car transmission was investigated by using simulation and fatigue limit diagram. The actual static stress of the root of teeth of a gear for a manual transmission was also measured by loading a certain torque on the input shaft. It is recommended that high speed gears are good targets for PM process.
Finally a frequency for each gear has been estimated under a certain condition. The result indicates that the requirement for each gear is completely different. Therefore there is possibility to derive the performance of materials more by optimizing secondary operations. A stress profile of a sprocket is also presented as another type of component that requires completely different performance.View full abstractDownload PDF (1410K) -
Hideshi Miura, Hiroyuki Maeda, Teruie Takemasu, Makoto Uemura, Masaaki ...2006 Volume 53 Issue 9 Pages 740-744
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSThis paper investigates the characteristic of single-layered and multi-layered compacts made by selective laser sintering using blended bimodal titanium powders. The surface texture and tensile strength were investigated by using single-layered compact. There were few defects in the surface of specimen sintered in vacuum, and the roughness was smoother than that of specimen sintered in argon. Maximum tensile strength of single-layered compact sintered in vacuum was about 200 MPa. The shrinkage and mechanical strength were investigated by using multi-layered compact. There was a unique tendency in the shrinkage of multi-layered compacts, which the density was around 76% and the adhesive bonding was not observed between layers, resulted in 70 MPa of maximum bending strength and 50 MPa of maximum tensile strength.View full abstractDownload PDF (793K) -
Toshiko Osada, Shigeo Tanaka, Kazuaki Nishiyabu, Hideshi Miura2006 Volume 53 Issue 9 Pages 745-749
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSIn this study, gas nitriding was performed to various sizes of Titanium parts which were produced by metal injection molding (MIM) process, in order to add the high functionality with low processing cost. It was shown from the experiments that the nitriding treatment was useful for increasing the hardness of the surface which microstructure changed to the TiN and acicular α-Ti phase. With respect to the effect on the size of parts, micro dumbbell specimen had around five times higher content of nitrogen than block ones. It was suggested that the size of μ-MIM products is so small that the surface treatment contribute significantly and easily to improve the properties, especially gas nitriding process is one of effective surface treatment methods for high functionality of μ-MIM products.View full abstractDownload PDF (967K) -
Yoshinori Itoh, Toshiaki Uematsu, Kenji Sato, Hideshi Miura, Mitsuo Ni ...2006 Volume 53 Issue 9 Pages 750-754
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSThe metal injection molding process was applied to produce the microstructual modified Ti-6Al-4V alloy compacts using Ti, 60Al-40V alloy and fine Mo powders. To improve the tensile properties of the compacts with modification of microstructure, the effect of Mo content and sintering conditions on the microstructures and mechanical properties of the sintered compacts were investigated, and the characteristic X-ray images were also measured by means of electron probe micro analyzer to estimate the distribution of added Mo.
The microstructures of sintered compacts were consisted of acicular α and intergranular β phases and the acicular α phase became fine with increasing Mo contents. The tensile strength of sintered compacts increased with increasing Mo contents. Although the elongation of sintered compacts slightly reduced with increasing Mo contents, these sintered compacts showed excellent ductility above 10% of elongation up to 4mass% of Mo contents. Eventually, the mechanical properties of the sintered compacts added 4mass% of Mo were improved to be 970MPa with 13.8% of elongation due to the fine microstructure.View full abstractDownload PDF (1404K) -
Toshiaki Uematsu, Yoshinori Itoh, Kenji Sato, Hideshi Miura2006 Volume 53 Issue 9 Pages 755-759
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSTi and Ti alloys show superior properties of lightweight, high strength and corrosion resistance, etc. Since Ti is very active at high temperature, the mechanical properties may be poor due to the oxygen and carbon contamination caused by type of substrate at high temperature and long time sintering. In this study, the effects of substrate for sintering on the mechanical properties of injection molded Ti-6Al-4V alloy were investigated using two types of substrates such as ZrO2 and Y2O3 (as-received or baked in vacuum).
The relative density, microstructure and hardness of sintered compacts were changed hardly, but the tensile properties were changed by baking treatment and type of substrate for sintering. The oxygen content of the sintered compacts by using as-received ZrO2 substrate increased with increasing sintering time, then the elongation of the compacts were reduced. While the compacts using the baked ZrO2 and Y2O3 substrates showed good tensile properties because of low carbon and oxygen content.View full abstractDownload PDF (1535K)
Memorial Lecture of JSPM Award
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Establishment of the Scientific Underpinnings in Powder Injection Molding and Liquid Phase SinteringRandall M. German2006 Volume 53 Issue 9 Pages 760-768
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSPowder injection molding and liquid phase sintering share common features with respect to the rheological response of the solid-liquid-pore system. Injection molding of powders dates from the 1930s, and liquid phase sintering of metallic powders dates from about that same time. Both processes share a strong sensitivity of viscosity to solid content and temperature, but there are differences. Accordingly, a model is introduced that includes factors as strain rate, grain size, solid content, and degree of grain bonding. In liquid phase sintering there is solid solubility in the liquid, which influences the time-dependent viscosity through grain bonding. Similarly, in powder injection molding the entanglement of long polymers leads to a time-dependent viscosity. Thus, both powder injection molding and liquid phase sintering show similarities that support a model for the rheological response useful in computer simulations.View full abstractDownload PDF (1440K)
Review
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Berm-Ha Cha, Yun-Sung Kang, Jai- Sung Lee2006 Volume 53 Issue 9 Pages 769-775
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSThis paper provides an overview on our recent investigations on the processing of net-shaped Fe-Ni nanoalloy powder and related material properties. The key-process for fabricating fully densified net-shaped nanopowder by pressureless sintering is an optimal control of agglomerate size of nanopowder. Especially, the pressureless sintering process is inevitable for consolidation of the Powder Injection Molded nanopowder. The mechanical- and corrosion properties of the PIMed Fe-Ni nanopowder are discussed in association with the microstructure of sintered nanoagglomerate powder.View full abstractDownload PDF (1544K)
Rapid Communication
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Kazuaki Nishiyabu, Satoru Matsuzaki, Shigeo Tanaka2006 Volume 53 Issue 9 Pages 776-781
Published: 2006
Released on J-STAGE: February 06, 2007
JOURNAL OPEN ACCESSA production method for porous metal components has been developed by applying powder space holder (PSH) method to metal powder injection molding (MIM) process. The PSH-MIM method has an industrial advantage which is capable of net-shape manufacturing the micro-size porous metal products with complicated shapes and controlled porosity and pore size. In this study, a small impeller made of stainless steel 316L was manufactured by injection molding, and a plate specimen was produced by extrusion molding to evaluate the dimensional accuracy of the porous sintered parts produced by the PSH-MIM method. The effects of combinations of size and fraction of space holder particle on the dimensional deviation and its coefficient of variance were investigated. It was concluded that the PSH-MIM method could manufacture commercially micro-porous metal components with high dimensional accuracy.View full abstractDownload PDF (1282K)
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