Microstructural and environmental effects on fretting fatigue

Fretting fatigue characteristics of two microstructures of a .40 .50 carbon steel are discussed in terms of the relative effects of mechanical and corrosive damage. Comparison of vacuum and laboratory air fretting fatigue data of each microstructure verifies the hypothesis that the mechanical damage incurred during the fretting process is of more consequence than the chemical damage due to oxide formation. A microstructural effect is evidenced in that the region of data over which decreases in life become significant is different for each microstructure. The microstructures investigated were a ferrite-pearlite structure in the as-received sheet form and a tempered martensite structure of higher strength.