Influence of Tempering Temperature on Low Cycle Fatigue of High Strength Steel

Abstract

In this study, the mechanical and low cycle fatigue properties for a heat-treatment steel subjected to quenching and tempering (QT) were evaluated. The steel had a modified chemical composition with respect to a conventional material and was subjected to tempering at various temperatures. It was shown that the material tempered at 250 degrees C exhibited superior fatigue properties in the short life regions. Carbon atom clusters in concentration of 18 at% in martensite were observed using atom probe tomography (APT) for the steel tempered at 250 degrees C. It is believed that these clusters contribute to the improvement of fatigue properties by hindering the motion of dislocations.