Temperature dependence of stress–lifetime fatigue curves

By analysing several finite-life fatigue curves obtained at various temperatures, a relation describing the temperature dependence of fatigue strength is proposed, based on the Basquin equation. Accordingly, an approximate inverse law between fatigue strength and the square root of absolute temperature is demonstrated. Moreover, a boundary temperature above which creep begins to play a significant role is estimated. A simple extension of the relationship to the low-cycle fatigue region, allows one to determine predictive curves describing fatigue behaviour at various temperatures, even in cases where only a single fatigue curve at a given temperature plus the temperature dependence of tensile strength are known.