An optimized hardness model for carburizing-quenching of low carbon alloy steel

Abstract

Research has been conducted about the hardness prediction for the carburizing and quenching process based on an optimized hardness simulation model, in accordance with the calculation rule of mixed phases. The coupling field model incorporates carburizing field analysis, temperature field analysis, phase transformation kinetics analysis and a modified hardness calculation model. In determination of the calculation model for hardness, calculation equations are given to be applied to low carbon content (x(C)≤0.5%) for the child phases and the martensite hardness is calculated for high carbon content (x(C)>0.5%) in alloy. Then, the complete carburizing-quenching hardness calculation model is built, and the hardness simulation data are corrected considering the influence of residual austenite (RA) on hardness. Hardness simulations of the carburizing and quenching process of 17CrNiMo6 samples have been performed using DEFORM-HT_V10.2 and MATLAB R2013a. Finally, a series of comparisons of simulation results and measured values show a good agreement between them, which validates the accuracy of the proposed mathematical model.

Keywords

carburizing-quenching simulation / hardness model / DEFORM-HT / residual austenite / high carbon content

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