A fatigue life assessment of 0.8%C spray-formed steel

The fatigue fracture process in 0.8%C spray-formed steel has been investigated. Two groups of data result from reverse fatigue tests and from surface replicas of test samples. Fatigue life-time data demonstrate a large scatter at the same load level. The spray-formed steel has been studied as a continuous random accumulation of flaws in the material. The full morphology is related to pores and short cracks on the surface of the samples tested under different levels of stress. The microlevel background of the Markov process simulation of short crack propagation is discussed. A two-dimensional Markov process is introduced for the modelling of the short crack development in a local area and for a reliability estimation of spray-formed steel behaviour.