Low Cycle Fatigue Life Estimation of Pearlite Base Cast Irons.

In this study the auther carried out low cycle fatigue tests at room temperature in use of the flake graphite cast iron (FC-P) and the spheroidal graphite cast iron (FCD-P) of pearlite matrix structure, and then proceeded to estimate the fatigue life of the said two kinds of cast irons. Fatigue life prediction was made for each one of the testing materials in different graphite shapes by the Manson's universal slope method. As a result, the estimated life of FC-P was nearly as long as the life obtained from the experiment, but that of FCD-P was about 20% shorter than the one obtained from the experiment. Hence, the author introduced the modified universal slope method based on the plastic strain component under the Manson-Coffin rule obtained from the experiment, and applied it to the both testing materials. In this way, it became possible for the low cycle fatigue life of the two kinds of cast irons to be guided collectively by one formula.