A new approach to the Haigh diagram of sintered steels from unalloyed iron to heat treated conditions

Abstract

Systematic investigations on the fatigue strength of heat treated sintered steels with notched specimens are barely found in the literature, especially at stress ratios other than R = −1. For that reason a larger study was initiated with the aim to provide a base for safe estimates of fatigue strengths also for heat treated components. This work deals with one possibility to design a Haigh diagram for the positive mean stress range beyond R = −1. Starting point is a new approach to determine the mean stress sensitivity M. As all equations derived are based on averages, in extreme cases individual test results can deviate by more than 20% from the calculated value. Regularly, however, deviations around ±10% are observed.