A novel method for predicting carburizing and quenching deformation of the gear with the mandrel based on carburizing expansion strain and dynamic thermal boundary conditions of quenching

Abstract

During the carburizing quenching process, the interaction of multiple physical fields leads to significant nonlinearity in the mechanical properties and physical characteristics of the material, making prediction of carburizing quenching deformation particularly challenging. Based on the phase transformation thermo-elastic-plastic constitutive equation, this paper innovatively incorporated the deformation of interstitial solid solution induced by carburization, and integrated experimental data on material properties for 8620RH, a multi-field model for carburizing quenching was constructed. The accuracy of the proposed deformation prediction model was validated through experiments on cylindrical samples and the calculation results from specialized heat treatment software Dante. Based on the deformation prediction model, considering the flow effect of quenching medium in gear quenching process, and introducing dynamic heat boundary conditions during quenching, a finite element model for predicting carburizing and quenching deformation of the gear with the mandrel was constructed to study the deformation distribution of the gear. The accuracy of the deformation prediction model was verified through the carburizing quenching experiment of the gear with the mandrel. The results show that compared with the classical model which does not consider the carburizing expansion strain and the dynamic thermal boundary conditions, the proposed model demonstrates higher predictive accuracy in torsional deformation and expansion deformation. The research work provides a novel model and method for improving the accuracy of predicting carburizing and quenching deformation in gears.