Regularities of the distribution of bounded fatigue limit of specimens of steel 45 with electrolytic iron coating

Abstract

1. The upper and lower bounds of the bounded fatigue limit of the bimetal steel 45 + coating were determined, and also the other parameters of the empirical distributions, on two test bases: N = 5·105 and l06 cycles. Fatigue curves with probability of failure equal to zero and to unity were plotted. 2. It was established that the scatter of the bounded fatigue limit of the bimetal depends on the test base: With increasing test base it diminishes. The variation coefficient of the bounded fatigue limit of the bimetal depends weakly on the test base, and the hypothesis of its being constant is accepted. 3. Probability diagrams of fatigue were plotted in coordinates P-N, δa-N, and P-δa; this made it possible to examine the regularities of the scatter of the bounded fatigue limit of steel 45 with electrolytic iron and to determine the type of distribution function. By unifying the mentioned diagrams, it is possible to plot the full probability diagram of fatigue δa-N-P of steel 45 with electrolytic iron.