Study on Very High Cycle Fatigue Fracture of High Strength Steel with CFB/M Complex Microstructure
The influence of production conditions and Nb microalloy on the very high cycle fatigue (VHCF) behaviors of different Carbide-free bainite/martensite (CFB/M) steels was studied, which include steels produced in laboratory and steelworks. Results show the Nb-microalloy can strengthen the microstructure including the soft bainite plate and improve the VHCF property evidently. In addition, the high purity of steels can avoid inclusion induced crack initiation, but can not improve the VHCF property unless the microstructure possesses favorable uniformity. The critical inclusion size is suggested to be 10-15μm and the CFB/M complex microstructure may be less sensitive to inclusions than other high strength steels.
T. Chandra, N. Wanderka, W. Reimers , M. Ionescu
Y. Yu et al., "Study on Very High Cycle Fatigue Fracture of High Strength Steel with CFB/M Complex Microstructure", Materials Science Forum, Vols. 638-642, pp. 3839-3845, 2010