Abstract: High-temperature fatigue tests were conducted on 30Cr1Mo1V steel under different stresses (450$\rightleftharpoons$0, 400$\rightleftharpoons$0, 350$\rightleftharpoons$0, 350$\rightleftharpoons$233, 350$\rightleftharpoons$175 MPa) at 540 ℃. The results indicate that the fatigue life of the 30Cr1Mo1V steel decreases rapidly as the peak stress exceeds 350 MPa. Under a stress of 350 MPa, the ferrite does not change too much, which maintains the initial polygon-like shape, and the ultimate failure feature of the steel is fatigue cracking. Nevertheless, when the stress rises to 400 MPa, the ferrite deforms remarkably and shows a wrinkled river-like shape after fatigue failure, meanwhile, the pores also appears at the intersection location of the ferrite bands. In addition, subjecting the long-term high stress level like at 350$\rightleftharpoons$233 MPa and 350$\rightleftharpoons$175 MPa are harmful to the fatigue life of the 30Cr1Mo1V steel, as continuous stress can significantly increase the number of fatigue pores inside the material. In summary, the 30Cr1Mo1V steel is relatively safe under service conditions of 540 ℃/350 MPa, with a fatigue life of 12 887 cycles, and a one-time attrition rate of approximately 0.007 76% which is less than the requirement of 0.01%.

Key words: 30Cr1Mo1V rotor steel, high-temperature fatigue life, microstructure