FRETTING DAMAGE OF SUS 304 IN A VACUUM.

Fretting damage morphology was investigated for SUS 304 stainless steel in a vacuum (4 multiplied by 10** minus **3Pa) by varying the number of fretting cycles, normal load, and slip amplitude, and the generation of surface cracks was examined by SEM. The condition for the generation of cracks and the crack morphology depended on both load and slip amplitude. Cracks were initiated at the boundary between fretted and unfretted areas after a certain number of cycles. Long cracks were formed under lower loads and short cracks were formed under higher loads at a constant slip amplitude. The length of a crack increased with an increase in slip amplitude, followed by a stop in crack generation at a certain slip amplitude under a constant load. The slip amplitude for the limitation of crack generation was approximately proportional to the load.