抄録
It is very important that the behavior of structurals will be studied under repeated impact loads, but there have been few papers hitherto published about impact fatigue since few efficient impact fatigue testing machines have been made available.
So, we devised a new rotating disk type impact fatigue testing machine, of which the impact velocity and the number of impacts per minute were 5.5m/sec and 600 respectively, and studied the effects of microstructure on the impact fatigue lives.
The 0.24% carbon steels, and 0.85% carbon steels with lamellar and spheroidal pearlite structure were used, of which some were annealed while others were left as they were when obtained.
The results obtained are as follows.
(1) The impact fatigue lives of 0.24% carbon steels were longer than those of 0.85% carbon steels, and the slopes of S-N curves of the former were steeper than those of the latter.
(2) The impact fatigue life of the annealed 0.24% carbon steel was longer than that of the 0.24% carbon steel that was left as it was.
(3) The impact fatigue life of 0.85% carbon steel with lamellar pearlite structure was almost the same as that of 0.85% carbon steel with spheroidal pearlite structure.
