1988 Volume 74 Issue 4 Pages 725-732
Fretting fatigue tests of high strength steels having ultimate tensile strengths of 490, 690 and 880 MPa were carried out in sea water under free corrosion condition, and the effect of fretting damage on fatigue life was investigated. At high stress amplitude, the higher the strength of steel, the longer the fretting fatigue life. At low stress amplitude, the fretting fatigue life of all the steels decreased to 10-20% of the conventional corrosion fatigue life and showed almost the same life irrespective of the strength of steel. The fretting fatigue life in sea water was much shorter than that in air, and the fretting fatigue strength at 107 cycles was lower in sea water than in air. The saturation of fretting fatigue damage occurred beyond a certain number of fretting cycles. The ratio of the smallest number of fretting cycles to the fretting fatigue life for the saturation to occur in sea water was less than 0.005%, but that in air was about 30%. It was shown that the fatigue life in sea water was lowered by the fretting damage of a small number of fretting cycles.
