Work

Austenite Decomposition Kinetics Model for Anchor Chain Steel Based on Continuous Cooling Dilatometric Curves with Nonisotropic Volume Change

Year: 2025

Type: article

Abstract: Accurate phase transformation kinetics model is crucial for establishing high‐strength anchor chain steel quenching numerical simulation. However, conventional modelling approaches have two inherent limitations, ignoring non‐isotropic volume changes during kinetics data extraction from dilatometric curves and obtaining continuous cooling phase transformation kinetic equation parameters from discrete isothermal experiment. These could lead to incorrect models that are not applicable to continuous cooling conditions. In this study, dilatometric tests were conducted under different continuous cooling conditions, combined with microstructural characterization and hardness measurements. A dilatometric curve analysis program that considers non‐isotropic volume changes was developed to extract kinetics data. The Johnson‐Mehl‐Avrami‐Kolmogorov (JMAK) equation parameters were fitted using the kinetics data, and the kinetic model was established. The model accurately reproduces continuous cooling transformation (CCT) diagram, with absolute errors below 5 °C for ferrite transformation temperatures and below 0.02 for phase fraction predictions. Furthermore, it is found that neglecting non‐isotropic volume change results in incorrect extraction of kinetics data, and that the CCT‐based approach is more suitable than the isothermal experiment‐based approach for obtaining continuous cooling kinetic equation parameters. The proposed model lays the foundation for quenching process simulation, and the proposed methodology can be extended to other steels and alloy systems.

Source: steel research international

DOI: 10.1002/srin.202500992