Balanced Constrained Carbon Equilibrium Accompanied by Carbide Precipitation

The article discusses the quenching and partitioning (Q&P) process of carbon steel, focusing on the prediction of carbon content in austenite. It introduces the Balanced Constrained Carbon Equilibrium (BCE θ) model, which modifies the existing Constrained Carbon Equilibrium (CCE) and CCE θ models by incorporating the mass balance of carbon. The BCE θ model considers the equilibrium between martensite, austenite, and carbide, and it is shown to provide more accurate predictions compared to previous models. The article includes detailed calculations and comparisons with experimental data, highlighting the advantages of the new model. The BCE θ model predicts an increase in carbon content in austenite as the temperature decreases below the martensite start (M S) temperature and shows a better fit to experimental data than the CCE and CCE θ models. The article concludes by emphasizing the importance of considering the mass balance of carbon in predicting the carbon content in austenite during Q&P treatment.