A rheological model aimed at accounting for the existence of two types of viscoplastic flow (microplastic and macroplastic) in 316 stainless steel is described in the most general state of stress. A distribution between active loadings (macroplastic strains) and unloadings (and/or loadings in a microplastic domain) made through a criterion essentially based on internal variables. A single internal variable is introduced in a single plastic state equation, the different behaviors being accounted for by the choice of the internal variable and of its hardening rules. Identification of these hardening laws are reported. It is seen that this model can predict a lot of various experimental observations in tensile, tensile-compression or tensile-compression-torsion tests. Numerical simulations of various tests extending from the tensile one to complex stress or strain paths in biaxial proportional loading are in a good quantitative agreement with the experimental results.

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