Concepts and experiments for characterizing plastic anisotropy of round bars ,wires and tubes

摘要

Starting from axial and radial anisotropy defined inprevious publications ,concepts for the description of plasticanisotropy of materials having axisymmetric properties (roundbars ,tubes ,wires )are defined .A maximum of three – in mostcases even less –independent parameters are needed .For solidmaterials like round bars I is recommended to use the axial-radialand the axial-tangential anisotropy as independent quantities forobtaining the yield locus according to Hill's quadratic yieldcriterion .Experiments for determining these parameters aredescribed .For tubes ,however ,in most cases only the radial-tangential anisotropy can be determined from the transversecontraction in tensile tests .Hence the yield locus can only beobtained in the approximation of the approximation of theHosford-Backofen yield criterion .Effects of the anisotropyparameters on metal forming processes are discussed.