High cycle fatigue behaviour of a standard duplex stainless steel plate and bar

The fatigue-life behaviour of an EN 1.4462 duplex stainless steel was characterised for two different products, namely a rolled plate and a hot rolled bar. The results indicate that strength characteristics, under both monotonic tensile and high cycle fatigue conditions, are lower for the bar than for the plate. Further, marked anisotropy effects are observed for the plate material with the transverse orientation exhibiting a higher mechanical response than the longitudinal one, independent of the testing conditions under comparison. The experimental findings may be rationalised, considering a direct correlation between crystallographic texture, quantified in terms of the Taylor factors for the individual phases, and crack nucleation resistance. In doing so, the latter parameter is assumed to be intimately associated with resistance to plastic deformation, i.e. flow stress, in agreement with the dominant cyclic deformation and crack nucleation mechanisms observed.