Abstract
In 1963, W. E. DUCKWORTH and E. INESON investigated the effects of non-metallic inclusions on fatigue life of En 24 steel using specimens which contained artificially introduced spherical or angular alumina particles with various controlled sizes. Their tests showed a large scatter of fatigue lives of specimens tested under the same stress level depending on the size and location of the inclusion at fracture origin. Their report revealed typical complicated aspects of the effects of non-metallic inclusions on fatigue strength.
In the present study, their complicated data were analyzed by the prediction equation which was proposed by MURAKAMI et al. and contains the Vickers hardness (HV) as the material parameter and the square root of projection area (√area) of inclusion as the geometrical parameter. The data can be clearly analyzed in a unified manner by MURAKAMI et al.'s equation. It is also shown that the shape of inclusions, spherical or angular, is not crucial factor of inclusion affecting fatigue strength.
