[in Japanese]

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Les résultats de microdureté se sont utilisés de temps en temps pour expliquer les phénomènes physiques qui existent dans les métaux. Cependant, dans l'essai de microdureté, les valeurs obtenus donnent la dispersion assez importante. Par consequent, pour constater la significativite des faibles phénoménes, on doit prendre les précautions soigneuses sur les measures de microdureté.
Pour ce point de vue, on a réalisé les améliorations suivantes sur l'essai de microdureté;
(1) utilisation des éprouvettes monocristallines du fer pur pour avoir l'homogénéite maximum de l'éprouvette et éviter les influences de précipitation des impuretés et de joint de grains;
(2) affaiblissement de la vitesse de la charge jusqu'à 50μ/s pour éviter l'augmentation de la dimension d'impreinte par l'inertie de sa vitesse;
(3) améliorations de la méthode de mesure de l'impreinte. Par ces améliorations réalisées, on a pu restreindre la dispersion des valeurs obtenus à ± 1, 2 Hv sous les conditions de la charge de 100g et de la vitesse de 50μ/s.
Avec cet avantage, on a confirmé le phénomène d'adoucissement de microdureté du fer pur monocristalline au cours de vieillissement en ambiante qui s'existe immediatement après trempe à l'eau de la température comprise entre 500 et 700°C.

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In order to improve the lapping efficiency of steel balls, has been developed a new lapping method. Instead of the upper lap plate being floating supported, as in the conventional lapping, it is used a supersonically vibrating plate.
In this paper, the results obtained from the fundamental experiments are described.
The major findings are as follow :
(1) Supersonic lapping under the optimum lapping conditions is superior to ability of conventional lapping caused by vibration.
(2) The lapped quantity has been affected not only by the impact energy but the lapping pressure, and in the case of lower amplitude was proportional to the lapping pressure, and vice versa to higher amplitude in the extent of this experimental conditions. (frequency 22 kc, amplitude 10-14.5 μ, lapping pressure 40-120 g per piece, ball dia. 2 mm)
(3) The increasing rate of sphericity per unit lapped quantity is generally related in inverse proportion to the impact energy, and has been affected by the impact energy rather than the lapping pressure.
(4) The physical and mechanical properties of the finished surface varied considerably according to the magnitude of impact energy and lapping pressure, and become better in the case with smaller the magnitude.

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The life and the final failure of the carbide cutting edge in the interrupted cutting when turning steel is ascertained experimentally in this paper, and these results are examined also by comparison with the life and the final failure of the cutting edge in the machining with or without chatters.
It is found that : The failures of the cutting edge in this machining differ completely from that in the machining with or without chatters. The cutting edge breaks down along its flank commonly, because the chipping of the cutting edge advance. Accordingly the ISO P20-tcol that has the superior properties for the machining with chatters, suits not always in the interrupted cutting, the H.S.S.-tool has a fair aptitude rather than the P20-tool in this machining.
And further, more when chatter vibrations of the tool for this machining occur, the carbide tool face flake off, and, the tool life is short-lived.

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Various synthetic resins were used as polishing plate for glass, supplying cerium oxide as polishing powder and water as polishing liquid.
Soft synthetic resins (except extremely soft resin), of which the hardness is below 540kg/mm² at 50100°C, are sufficiently applicable for polishing of glass at the proper polishing pressure, when relative speed between glass and polishing plate is about 10m/min.

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