Effect of tempering temperature on fatigue strength of Thyssen 6582 steel

Abstract

Fatigue tests under rotating bending fatigue testing machine has been carried out to estimate the effect of tempering temperature on fatigue strength of Thyssen 6582 machinery steel materials. The fatigue strength of these materials has been studied as a function of tempering temperature from 100 to 600°C test temperature with time hold up during 20 minute. The initiation and propagation behaviours of micro cracks were investigated on the specimen surface. The results show that the fatigue strength at 100°C was lower than at room temperature as standard specimen. The fatigue strength rates increasing as the tempering temperature increases to 300°C due to crack length occurs on the specimen surface, and then decreasing again with higher tempering temperatures. The ratio of fatigue strength and ultimate stress at 300°C was higher than at all of the tempering temperatures. The effect of tempering temperature on hardness, ultimate strength of materia! and the relationship between and microstructure are discussed.