Abstract.A fully-coupled model of quenching by submerging for steel workpieces is presented. The model includes cooling of the piece due to piece-to-bath heat transfer calculations by solving the multiphase problem of an evaporable fluid, as well as the corresponding metallurgical transformations, the generation of residual stresses and associated geometrical distortions. The heat transfer model takes into account different boiling stages, from film boiling at very high workpiece surface temperatures, to single-phase convection at surface temperatures below saturation. The evolution and activation of each heat transfer mechanism depend on the dynamics of the vapor-liquid multiphase system of the quenching bath. The multiphase flow was modeled using the drift-flux mixture model, including an equation of conservation of energy of the liquid phase. Metallurgical transformations, geometrical distortions and residual stresses at the end of the process, are obtained based on the different cooling rates along the piece. The final distribution of metallurgical phases is obtained by the integration of the thermal evolution and using information of the CCT diagrams of studied steels. The analysis of deformations and residual stresses takes into account elasto-plasticity (without viscosity effects), transformation induced plasticity and hardening restoring phenomena. Comparison of results considering the approach presented here versus a simplified heat transfer model indicates that the level of induced residual stresses are noticeable different implying the necessity of developing a more precise heat transfer quenching model.

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