Influence of Fretting on Flexural Fatigue of 304 Stainless Steel and Mild Steel

摘要

Fretting fatigue experiments were conducted on 304 stainless steel and on mild steel. The test configuration was a flexural fatigue arrangement, with mild steel fret¬ting pads bolted onto the fatigue specimen. Experiments were conducted at room temperature in air.nFretting reduced the flexural fatigue life of 304 stainless steel by at least a factor of 10 at alternating flexural-fatigue stresses in the 265- to 334-megapascal range. In addition, experiments in which the fretting pads were removed after a number of cycles followed by continued fatigue without fretting showed that continued fretting be¬yond 50 000 cycles does not significantly further reduce the fatigue life of 304 stainless steel at 317 megapascals (46 000 psi). Microscopic examination indicated that failures invariably began in the fretting region. Cracks that did not propagate to failure were also observed in the fretted areas.