Abstract: Numerical simulation method and elasticplastic con- stitutive relation with hybrid hardening are adopted, the stress compensation updating algorithm based on elastic tensor is brought forward, isotropic hardening coefficient is introduced, the steps for computation of the elastic-plastic constitutive relation in FEM are given, and the subroutine VUAMT is developed on the plat of ABAQUS/Explicit, whose reliability is verified by a single element model. Apply the subroutine in cold ring rolling simulation and pay emphasis on the regularity of the effects that coefficient does on the isotropic hardening process of cold ring rolling. The results show that draught pressure and roll torque increase, fishtail coefficient decreases with the increase of isotropic hardening coefficient; anisotropic hardening does more effects on the metal near the outer of the ring. Theoretic analysis on the regularity above is given further. The conclusion can do instruction to the process of cold ring rolling in factory.

Key words: Cold ring rolling, Constitutive relation, FEM, Hybrid hardening