Abstract
Fretting fatigue tests of high strength stainless steel 440C were carried out to investigate the basic properties of fretting fatigue and the effects of contact material and variable loading on fretting fatigue strength. The fatigue life and the fatigue limit of 440C steel decreased significantly under the fretting fatigue condition. A soft contact material was effective to improve the fretting fatigue strength. The difference in fatigue life among contact materials will be caused by the difference in the concentration of frictional force in the edge region of contact surface: The softer the contact material, the lower the concentration of frictional force. Therefore, the softer contact material induces the lower acceleration of crack growth rate, and gives the higher fatigue limit and the longer fatigue life. The modified Miner's rule seemed to hold in the case of fretting fatigue under a program loading simulating the actual load of bearing for airplane.
