All issues
Volume 46, Issue 5
Displaying 1-17 of 17 articles from this issue
- |<
- <
- 1
- >
- >|
-
Masato Sagawa1999 Volume 46 Issue 5 Pages 457-462
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA brief review is given about the researches on rare earth permanent magnets conducted in 15 years since the NdFeB permanent magnet was presented. It is then pointed out that important subjects left behind are development of a net-shape-process for NdFeB sintered magnets and development of NdFeB sintered magnets containing not much Dy that can be used up to 200°C or so. To develop such magnets, the mechanism of nucleation of reversed domain has to be clarified.View full abstractDownload PDF (2407K) -
Performance of A New Chip Breaker in Wet TurningShinsaku Hanasaki, Junsuke Fujiwara, Tadahiro Wada1999 Volume 46 Issue 5 Pages 465-471
Published: May 15, 1999
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSA new chip breaker was investigated experimentally in order to find out a more effective chip breaker than the commercial chip breaker in turning. It was found that this chip breaker was almost effective for SS400, SCM440, S55C, SUS304, SK5 under the cutting condition of the depth of cut 0.1 to 3.0mm and the feed rate 0.05 to 0.51mm/rev. However, the plastic deformation of the nose corner on the insert occurred under the cutting condition of large depth of cut and high feed rate, especially for SCM440. This seems to be caused by the rise of cutting temperature.So, in order to cool the insert, the water-soluble cutting fluid was used. In wet cutting, the effectiveness of this chip breaker was improved. The principal and feed cutting forces in wet cutting were a little greater than that of dry cutting under a small depth of cut, but became slightly less under large depth of cut. The effectiveness of chip breaking of this chip breaker was kept up to the width of the flank wear 0.2mm in wet cutting. In wet cutting, the plastic deformation of the nose corner was reduced.View full abstractDownload PDF (3069K) -
Tetsuji Hoshika, Yutaka Hiraoka1999 Volume 46 Issue 5 Pages 472-477
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSCarbon addition was performed for doped molybdenum having two kinds of grain structures, large and elongated grain structure and relatively small and elongated grain structure. The three-point bend tests were performed for these samples. In this study low-temperature fracture strength and ductility was represented by two parameters; critical stress and critical temperature respectively. Then their fracture surfaces were examined by using a scanning electron microscopy, and crack generation and propagation characteristics were investigated.
The fracture strength of doped molybdenum was generally improved by a small addition of carbon, but the mechanism of improvement was different depending on the grain structure. In case of large and elongated grain structure, the increase of strength was attributed to the strengthening of the small grain (s), which was identified as the crack generation site. On the other hand, in case of relatively small and elongated grain structure the increase of strength was attributed to the strengthening of the whole grain boundaries. The ductility of doped molybdenum was also improved by a small addition of carbon. This result was mainly attributed to the increase of the fracture strength.View full abstractDownload PDF (4942K) -
Toshiya Matsui, Ryu Murakami, Jun Takada1999 Volume 46 Issue 5 Pages 478-483
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMost of the iron objects dug out from the archaeological sites in Japan have been corroded. The further corrosion of cast iron objects proceeds after excavation, and the objects become to decay quickly. For the conservation of the iron objects, which are common cultural properties from our ancient, for the coming age, it is of great importance to know the origin or process of corrosion. The distribution of the corrosion accelerating anions (such as chloride ion or sulfite ion.) have been investigated in these cast iron objects of 16th-19th century. The hyper-eutectic iron object contained chloride ion at center of carbon flakes in metallic and its surface have been corroded with a scale pattern at plates of carbon flakes. The iron objects with Ledeburite structure show strong corrosion resistant, but it cracks to a fine block and decay. An iron object of 19th century has been kept the shape with the eutectic of the phosphide compound, called steadite structure. The types of corrosion process of the archaeological cast iron objects have been controlled by the metallographic phases.View full abstractDownload PDF (8128K) -
Shuji Wanikawa, Satoshi Emura, Masuo Hagiwara1999 Volume 46 Issue 5 Pages 484-488
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSTitanium-based composites reinforced with TiC particles were produced by the mechanical alloying processing route using the planetary ball mill. The titanium powder with a particle size smaller than 44μm (-325mesh) and carbon powder with an average diameter of 0.64/μm were used as starting powder materials. The average particle size of TiC which was formed during milling treatment decreased with the increase of disk rotation speed and milling time. It was possible to coarsen TiC by annealing the milled and HIP'ed compacts in the temperature range above 1, 273K. Under the milling and annealing conditions used in the present study, the average particle size of TiC ranged from 2μm to around 20μm. The tensile properties of the composites were measured as a function of volume amount of Ti Cand TiC particle size. In the case when the TiC particle size remained constant, the tensile strength of the composites increased whereas ductility decreased with increasing amount of TiC. In the composites reinforced with 10 volume % TiC, tensile strength and ductility showed higher values as the TiC paticle size decreased.View full abstractDownload PDF (3853K) -
Tomohiro Takida, Tadashi Igarashi, Isao Mutoh, Tatsuhiko Tanabe1999 Volume 46 Issue 5 Pages 489-495
Published: May 15, 1999
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSMolybdenum sheets with two types of elongated coarse-grain structures (trade name: TEM) were developed by heavy-duty rolling and recrystallization treatment of sintered molybdenum bodies with 1mass% La2O3. One type of sheets has spindle-like grains (S-TEM), and the other has stacked, plate-like grains (P-TEM). Tensile tests were carried out on S-TEM and P-TEM at 1470K to 2070K in vacuum to investigate the effects of grain structure on tensile properties such as proof strength (σy), tensile strength (σm) and uniform elongation (δm) at high temperatures. The aspect ratio (LTD/W, LRD/W) of grains, i.e., ratio of grain length (L) to grain width (W) on the transverse plane and perpendicular plane to the rolling direction, were estimated as a parameter of grain structure. The following results were obtained.
(1) TEM with elongated coarse-grain structures (S-TEM and P-TEM) had a higher σy and σm than pure molybdenum and TZM with equiaxial-grain structures. At 2070K, the σy and σm of TEM were 2-3 times those of pure molybdenum.
(2) The σy and σm of TEM increased with increased LTD/W, and strain hardening was difficult to perform with increased LRD/W.
(3) Three distinct failure modes were found. The higher the test temperature, the smaller the reduction area in the case of S-TEM with small LTD/W grains. In P-TEM with large LTD/W grains, the reduction was not dependent on temperature, although P-TEM indicated a larger reduction compared to S-TEM. In pure molybdenum and TZM, the higher the test temperature, the larger the reduction.View full abstractDownload PDF (5192K) -
Tomikatsu Kubo, Nobuya Machida, Hiroshi Sakai, Toshihiko Shigematsu1999 Volume 46 Issue 5 Pages 496-501
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe tetragonal to monoclinic (t-m) phase transition in 2.0 mol% yttria-doped tetragonal zirconia polycrystals (2Y-TZP) was studied by use of XRD and FT-IR diffuse scattering (DRIFT) measurements. The phase transition occurred isothermally when the 2Y-TZP powder after calcining at temperatures below 1200°C was annealed in air even at room temperature, and more than 90% of the monoclinic phase was obtained after a long period of annealing. However only about several percent and about 40% of the monoclinic phase were formed after the annealing treatments under vacuum and 1 atm air separately sealed in a 5 ml Pyrex tube, respectively. On the other hand, no phase transition occurred in air around room temperature in the 2Y-TZP powder after being calcined at temperatures above 1300°C. A broad band around 3300 cm-1 due to the existence of adsorbed water was observed in the FT-IR DRIFT spectra of the 2Y-TZP powder only after calcination below 1200°C. The t-m transition behavior of 2Y-TZP powder after calcination below 1200°C differed with that after calcination above 1300°C. The existence of adsorbed water on 2Y-TZP was essential for the t-m phase transition of 2Y-TZP to take place in air around room temperature. The amount of transformed monoclinc phase was determined by the amount of adsorbed water on 2Y-TZP and supplied water from annealing atmosphere.View full abstractDownload PDF (467K) -
[in Japanese]1999 Volume 46 Issue 5 Pages 504
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (101K) -
Powder Forging and ForgingSadao Ishihara1999 Volume 46 Issue 5 Pages 505-509
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSFor automobile engines, low fuel consumption and low emission technologies have been pursued while overcoming the difficulties such as two "oil-shocks", emission gas and CAFE regulations on Japanese automobiles. In addition, low noise and high performance requirements are increasing recently. In this paper, it is introduced that the high strength and light-weighted Connecting Rod development and usage status in Toyota, along with the selection between Powder Forging and Forging.View full abstractDownload PDF (407K) -
Akira Fujiki1999 Volume 46 Issue 5 Pages 510-518
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSNew P/M parts and materials are developed for high performance engines which show high power and torque with low emission and low fuel consumption.
As for P/M parts, sinter-joined sprocket is explained. In this development, materials selection and design are referred. Also new test method for torsion fatigue test is explained. Non destructive analytical technique is developed to evaluate joint area by ultrasonic.
As for P/M materials, development of P/M molybdenum steel base anti-wear materials are explained. These were developed for engine cam-followers and valve seat inserts. And also new valve/valve seat wear test apparatus are developed.View full abstractDownload PDF (6414K) -
Toshikatsu Koike, Hiroshi Yamagata1999 Volume 46 Issue 5 Pages 519-523
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA powder metallurgical aluminum alloy and forging technology have been developed to mass produce high-performance-engine pistons. An Al-Si based powder metallurgical alloy containing 2mass% SiC particles and 5mass% Fe has shown much higher fatigue strength as well as better wear resistance than a conventional cast piston alloy. In order to draw out the alloy's formability, the forging has been programmed using an integrated process that involves the precise control on the die temperatures and the spray conditions of the lubricant. With these procedures, near-net-shaped pistons are efficiently obtained. The newly developed pistons have improved engine performance and are being put into practical use in Yamaha's commercially available snowmobiles.View full abstractDownload PDF (3641K) -
Kazuhiko Shinohara, Masakazu Kobayashi, Keiko Kushibiki, Kennji Furuya ...1999 Volume 46 Issue 5 Pages 524-528
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIt is well known that almost 70% of energy of fuel is wasted as thermal energy in the case of gasoline engine vehicle. Utilizing the thermal energy to provide electric power for automobile instead of using the engine driven alternator, we can reduce the load for the alternator and save fuel. Thermoelectric generator can convert the thermal energy to electric energy directly. In order to realize the generator, it is necessary to increase the conversion efficiency of the thermoelectric material and to increase the heat transfer from exhaust gas to the thermoelectric module.View full abstractDownload PDF (4123K) -
Kenichi Miyauchi, Motokazu Kobayashi, Eiji Ogawa1999 Volume 46 Issue 5 Pages 529-532
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn order to satisfy the weight and cost reduction of camshaft for trucks and buses, and to improve its wear resistance, it is effective to adopt the composite camshaft which is connected by diffusion-join process between steel shaft and cam lobe. Damage mode between slipper type tappet which is widely adopted for OHV type diesel engines and cam lobe is scuffing and pitting. Thus, it has become necessary to adopt the sintered materials, for cam lobe, which has great resistance to scuffing and pitting. We have developed a Fe based sintered materials for cam lobe to be used together with widely adopted low cost hardened chilled-cast iron tappet. The material for cam lobe has great resistance to scuffing with precipitating of a large quantity of fine Cr-carbide, and has great resistance to pitting with strengthening the matrix by containing a proper amount of Mo and Ni.View full abstractDownload PDF (2561K) -
Junichi Asami, Katuhiro Kimura, Akira Umeda1999 Volume 46 Issue 5 Pages 533-537
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSCu-plated Fe powder by the use of the etching waste solution is produced. Since the amount of plated Cu can be regulated, the composition of plated powder in this study is controlled Fe-50wt%Cu. As the result, there is the excellent compactibity of plated powder and it is possible to sinter at low temperature. For instance, the rattler value of 0.25% was obtained by the compacting pressure of 294MPa and the radial crushing strength was 171MPa at the sintering temperature of 973K for 3.6ks. The sintered compacts of the plated powder in comparison with mixed
powder have the low dimensional change, the uniform in the pore distribution and reasonable mechanical strength. Conseqently this Cu-plated Fe powder appears to be very suitable oil-impregnated bearing. Furthermore, this sintered compact is very superior in roundness and cylindricity which are important from the standpoint of the precision of bearing.View full abstractDownload PDF (3620K) -
Mitsuru Nakamura, Noriaki Chida, Takeshi Ohba, Yoshimi Sugaya1999 Volume 46 Issue 5 Pages 538-543
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSFrom the purpose of rapid sintering technique within a few minutes, this study was used the green compact of die assembly's lubricant method. Specimen were composited 0.8mass%C-1.5mass%Cu-bal. Fe powders, and used to the high frequency induction heating instrument. By the rapid sintering method, there is very important factor both the removal of adsorbed gas in powder grain surface and accompanied by the diffusion and sintering of each powder. As a result, the isothermal treatment (1223K-90s) when the sintering process in this experiment was a key technology treatment. That is to say, this new sintering method obtaind more radial crushing strength values than that of the conventional furnance process. This method was finished to sinter only 3 minutes, and it's condition was maximum heating time-30s, sintering condition 1523K-60s and isothermal treatment-90s holding only.View full abstractDownload PDF (8009K) -
Takatoshi Takikawa, Ryuji Shiga, Yoshinobu Takeda1999 Volume 46 Issue 5 Pages 544-547
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDevelopment of heat treated PM steel parts with high dimensional tolerance was conducted.
Calibration of dimensions by repressing (sizing) of sintered steel parts is commonly used, however it is not used for heat treated sintered steel parts because of their high hardness. As heat treatment usually deteriorates dimensional tolerances of sintered steel parts, expensive finish machining or grinding is often required.
A new method of Marquench-Repressing, simultaneous quenching and repressing of undercooled austenite, enables calibration of dimension along with martensite transformation in a single step.
Fe-Mo-Cu-C alloy was selected and processed. Significant improvement both in dimensional tolerance and mechanical properties was confirmed.View full abstractDownload PDF (3706K) -
Takayuki Hirao, Akira Fujiki, Masaki Saitou, Shunzou Umegaki, Takeshi ...1999 Volume 46 Issue 5 Pages 548-553
Published: May 15, 1999
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn standard P/M (Press-Sinter) technique, it is difficult to make under-cut shape parts. In this development, under-cut shape sprocket of whole circumference is made by CNC press and new designed die and tools. This paper describes the details of this development. 1) Features of CNC press and new designed die and tools for under-cut shape compacting. 2) How to eliminate cracks and barrs of this under-cut shape parts. 3) How to achieve the even density of this complex parts. 4) How to keep the dimensional tolerance of this parts.View full abstractDownload PDF (3655K)
- |<
- <
- 1
- >
- >|