Mean stress effect on fatigue strength of stainless steel

Influence of mean stress on fatigue life and fatigue limit was investigated for Type 316 stainless steel. The results for prestrained specimens revealed that fatigue life was almost the same in the same strain range regardless of stress amplitude, maximum peak stress and mean strain. The fatigue life was shortened when applying the mean stress for the same strain range, whereas it was increased for the same stress amplitude. It was shown that the reduction in fatigue life was brought about by the change in the effective strain range, which was caused by the increase in minimum peak stress and the ratcheting strain. The fatigue life could be predicted conservatively even if the mean strain was applied by assuming the effective strain range to be equal to the total strain range (by assuming the crack mouth to be never closed). It was concluded that the mean stress correction was not necessary for the load-controlled cyclic loading and for the region where the ratcheting strain was constrained.     

The effect of working media on the fatigue strength of steel under high-frequency loads

The effect of working media on the fatigue strength of metals in the load frequency range 10–20 kHz/sec has not been extensively studied. While, a few years ago, it was believed [1] that in view of the short test duration at such high frequencies the influence of corrosive media may be neglected, it is now known that this effect may be quite considerable.     

Control of austenite steel fatigue strength

The physical mechanisms of structure-phase states and dislocation substructures evolution and partial restoration of resource durability in conditions of pulse electric current stimulation at the intermediate stage of fatigue curve are established in austenite steels by method of transmission electron microscopy.