Impact of Quenching Intensity using a Finite Element Model to Investigate the Microstructure and Hardenability of Low-Alloy Steel - Tom Bell Young Author Award Candidate

Quenching is still one of the primary processes to improve mechanical properties in steels, particularly hardness. To obtain specific properties, different parameters must be controlled during quenching, for example chemical composition, and quench severity, among others. The end-quench Jominy test has been used extensively to study the hardenability of different steel grades. Different numerical, analytical, and empirical models have been developed for simulating the Jominy process and to understand quenching of steels. In this work, the approach was to utilize Finite Element Analysis (FEA) coupled thermal, mechanical, and metallurgical models to simulate the end-quench Jominy test and quenching of industrial round billets. For this purpose, a FEA method was employed using SIMHeat solver, a product of Transvalor S.A. Employing thermophysical properties and continuous cooling temperature curves generated from JmatPro software, it was possible to simulate the evolution of microstructure and hardness during quenching of AISI 4130, and AISI 4330 steel.

Furthermore, the Jominy setup was improved to incorporate measurements of temperature upon cooling the Jominy bar and water flow. With this information, cooling rates at different positions in the Jominy bar were determined and compared to numerical simulations. After verification and validation, the FEA model was utilized to predict different phases and hardness at different conditions in industry produced round billets. Additionally, relations between Jominy positions and radial positions in the billet were established based on the experimental and simulated cooling rates.