Abstract
A review is presented of the influence of composition on the work hardening behaviour of commercial grades of austenitic stainless steels. Depending upon the composition and temperature of working, these materials can deform via the formation of martensite or the generation of stacking faults in the fcc structure, producing marked differences in the mechanical properties. Whereas the flow stress in stable austenitic grades can not be adequately modelled by the traditional Ludwig relation, σ = Kεn, the problem can be resolved satisfactorily by the introduction of an additional term which accommodates the deviation from this relation at low strains. There is broad agreement in the literature that nickel and copper increase the stacking fault energy of austenitic stainless steels and that this parameter is decreased by additions of nitrogen, chromium, cobalt, and silicon. In unstable grades, it has been shown that the formation of strain induced martensite during fatigue testing reduces the crack propagation rate due to perturbation of the stress field around the advancing crack tip. Finally, consideration is given to the design of composition for the development of the optimum rate of work hardening in particular end applications.
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