Effect　of　Rare　Earth　Elements　on　Low　Frequency　Fatigue　Cyclic　Softening　of　Hot　Rolled　Steel　60CrMnMo　at　High　Temperature

The effect of rare earth (RE) on cyclic softening of low frequency fatigue of the hot rolled steel 60CrMnMo at high temperature was investigated. The hardness of specimens before thermal fatigue test and being cycled 180 times from room temperature to 650 degree C was compared. The results show that by adding a certain amount of RE in steel 60CrMnMo, the cyclic softening during low frequency fatigue test at high temperature can be restrained. The carbide particles were refined during tempering treatment and the agglomeration and growth of carbide particles can be obstructed during thermal cycle.