Numerical Modeling of Charpy Impact Toughness Behavior and Stress Distribution of Quenching and Partitioning Steel

The toughness of steel is a critical material property that represents the ability to absorb energy at fracture, particularly in ultra-high-strength steels. The optimal balance between high strength and ductility depends on the complexity of the microstructure formed during heat treatment, which influences the toughness of the steel. In this study, a numerical modeling approach was used to investigate the Charpy impact behavior of medium manganese Q&P (quenching and partitioning) steel with a focus on toughness and stress distribution. ANSYS Explicit Dynamics was used for numerical modeling to simulate stress distribution and energy absorption in Charpy specimens. The Johnson–Cook model approach was used to describe the material behavior for such dynamic conditions. The results showed that ductility and toughness decreased with increasing partitioning time from 300 s to 900 s. The simulation results also showed that the stress distribution was more pronounced near the notch radius. The absorbed energy of the samples increased slightly as the notch radius increased from 0.1 mm to 0.25 mm, and it significantly increased as the plate thickness increased from 7 mm to 12 mm.