Damage mechanism of 30Cr1Mo1V rotor steel during thermal fatigue at 540°C

Abstract This paper reports the damage mechanism of 30Cr1Mo1V rotor steel during thermal fatigue at 540°C. Detailed information on macro‐failure characteristics and micro‐failure mechanisms was revealed here. The results showed that both intragranular micro‐defects and intergranular micro‐crackings were formed during the fatigue process. The formation of intragranular micro‐defects was related to the dislocation tangle inside the ferrite sub‐grains, while the formation of intergranular micro‐cracking could be related to the weakening of atomic cohesion at the matrix/cementite interface. Eventually, the transgranular crackings occurred in the 30Cr1Mo1V steel. The morphology of these crackings presented an edge‐shaped discontinuity, which may propagate perpendicularly to the loading direction and cause the material to fracture.