抄録
The present investigation was carried out to clarify the influence of internal and external notch effects and effective cross section ratio on the fatigue strength of sintered irons prepared from fine and coarse particle sizes.
The results obtained were as follows:
(1) The internal notch factor of pore (βp) in specimens prepared from fine and coarse particle sizes was in the range 1.28 to 3.81.
Values of βp increased considerably as the sintered density and sintering time decreased, and as the powder particle size increased.
(2) The external notch factor (βn) of those specimens was in the range 1.01 to 1.47. Values of βn increased as the sintered density and sintering time increased, and as the powder particle size decreased.
In specimens having the same density, the external notch factors tended to be higher for the lower internal notch factors.
(3) The effective cross section ratio of those specimens decreased with the decrease in sintered densities and with the increase in powder particle sizes, resulting in the reduction of those fatigue strengths.
