可鍛鋳鉄における黒鉛の応力負担能力と疲労強度の関係

抄録

The fatigue tests were carried out to study the effects of elasticity and compactness of the graphites for two kinds of parlitic malleable irons, one was heat-treated by direct oil quenching and tempering process and the other was heat-treated by reheating, oil-quenching and tempering process. The material produced by direct oil quenching and tempering process in which graphites could be considered to be compressed by matrix, had about 20% higher fatigue strength in rotary bending fatigue test than that produced by reheating, oil-quenching and tempering process in which graphites exist more loosely. The similar results were obtained in torsional pulsating fatigue test on the universal joint yokes made by these two materials. Thus it was concluded that the fatigue strength was influenced by elasticity and compactness of graphites.