Fatigue behavior and life predictions of notched specimens made of QT and forged microalloyed steels

Fatigue behavior of notched specimens was investigated using circumferentially notched round bar and double-notched flat plate geometries, each with different stress concentration factors. Specimens were made of a commonly used vanadium-based microalloyed forging steel, in both the as-forged and quenched and tempered (QT) conditions. The effects of different notch severities and constraint conditions (i.e. plane stress versus plane strain) on fatigue behavior, and the ability of S–N and strain-life approaches to correlate and predict the experimental data are examined. Notched fatigue behavior of the microalloyed steel is evaluated and compared with its QT counterpart.