The mechanical properties of the supercooled austenite phase are sensitive parameters for the prediction of distortion of the components during heat treatments as the inelastic deformation occurs mostly on the soft austenite phase. Recent studies clarified that one of the overlooked issues related with the thermomechanical behavior of supercooled austenite during heat treatment and welding is its complicated cyclic hardening behavior (cf. Simsir et al., Acta Materialia, 2010). Based on those concerns, this article presents an optimization method for determination of temperature-dependent parameters for an Armstrong-Frederick model with combined non-linear kinematic and isotropic hardening, which can potentially pull the quality of simulations through. The results indicate that the proposed approach yields satisfactory results for simulation of heat treatments and welding even with a small and imperfect experimental data pool. (C) 2010 Elsevier B.V. All rights reserved.