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Volume 28, Issue 3
Displaying 1-6 of 6 articles from this issue
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[in Japanese]1981 Volume 28 Issue 3 Pages 83-89
Published: April 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (6341K) -
Junjiro Takekawa, Yoshimichi Masuda1981 Volume 28 Issue 3 Pages 90-94
Published: April 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe yield criteria for green compacts of iron and copper powders were determined by means of the uniaxial compression and the triaxial compression tests. In the triaxial test under the condition, preventing the increase in the density of the compacts by the hydrostatic confining pressure, the decrease in the apparent Young's modulus and a large plastic deformation of the compacts with the increase in the confined pressure were observed. The yield-loci for the compacts are of a type in which the second invariant of the stress deviator decreases with the increase in the mean stress, and which is consistent with the compressive behavior of metal powder compacts.
The experimentally determined yield-loci for the copper compacts agreed very closely with those theoretically calculated by R. J. Green.View full abstractDownload PDF (351K) -
On the Case of Using High Viscosity Lubricant OilTohru Kohno, Yoshio Nishino1981 Volume 28 Issue 3 Pages 95-100
Published: April 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSUsing the lubricant oil with relatively high viscosity, the lubrication mechanism of oil impregnated sintered bearings was discussed in a region of lighter load and higher speed revolution (P;2-6kg/cm2, N;4, 000-24, 000rpm, V;100-600m/min) comparing with ordinary running conditions.
In the running conditions above mentioned, even sintered bearings can be driven under hydrodynamic lubrication after achieving a sufficient "geometrical conformity" of high speed revolutions (over than about 20, 000rpm). In the region like these, therefore, we cannot conventionally evaluate the degree of severeness of running condition for sintered bearings by the PV value.
It was found that a linearity exists between the bearing temperature and PVμ which is proportional to the energy produced on the sliding surface. It is to be noted that the linearity relationship is valid regardless of the type of lubrication, i.e. regardless of whether it is hydrodynamic or boundary.View full abstractDownload PDF (3435K) -
On the Case of Using Low Viscosity Lubricant OilTohru Kohno, Yoshio Nishino1981 Volume 28 Issue 3 Pages 101-104
Published: April 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSUsing the lubricant oil with relatively low viscosity, the lubrication mechanism of oil impregnated sintered bearings was discussed in the same region as the former experiment (1st Report).
It was found that the aspect of lubrication is similar to that of the former experiment with relatively high viscosity oil, i.e. through the boundary state at low speed revolution, the bearing can be driven under hydrodynamic state at about 24, 000 rpm. In the former experiment, it was found that the bearing can be driven under hydrodynamic state at about 20, 000 rpm. This difference is caused by the difference of the thickness of lubricant oil film due to the different viscosity.
In the region of low speed revolution through the high speed one, essential features of boundary lubrication of the sintered bearing were recognized. This is caused by the pressure drop of the lubricant oil film on the sliding surface because of the leakage of the pressure into the pores, although the absolute values of the friction coefficient are relatively small. Therefore, in the region as this experiment, one cannot discuss the lubrication mechanism by the values of the friction coefficient.View full abstractDownload PDF (1743K) -
Its Revealing ProceduresSachio Oki, Keiichiro Shoji1981 Volume 28 Issue 3 Pages 105-107
Published: April 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA study has been made on the polishing method to reveal real pore structure in sintered steel metallographic specimens.
A fractional part of pore was observed in the surface when it was examined as polished state, but after several cycles of re-etching and lightly repolishing, real pore structure was revealed.
The morphology of the pore structure was not smeared by this method.View full abstractDownload PDF (3307K) -
Koji Hayashi, Hisashi Suzuki1981 Volume 28 Issue 3 Pages 108-109
Published: April 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe effect of ruthenium addition (up to 0.4%) on the basic properties of WC-10%Co and WC-33%β-12%Co alloys was studied. The properties of these alloys such as transverse-rupture strength and loaddeflection curves, hardness, and cutting performance (at temperatures below 1273K), were almost not affected by the ruthenium addition, though it was observed that the carbide grain size of WC-Co alloy was somewhat reduced.View full abstractDownload PDF (1541K)
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