Quenching is one of the primary processes to improve mechanical properties in steels, particularly hardness. Quenching is well established for different geometries of individually treated steel components; while in-steam quenching of large diameter continuously cast steel bar has several specific features which are difficult and costly to experimentally optimize. 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 to simulate the Jominy process and to understand quenching of steels. However, it is not straight forward to translate experimental data from Jominy test on instream quenched large diameter continuously cast products. Therefore, in this work, coupled thermal, mechanical, and metallurgical models were used to simulate the end-quench Jominy test and in-stream quenched industrial round billets with a goal to obtain similarity of experimental structure and properties for both quenched products. For this purpose, finite element analysis (FEA) was employed using the software FORGE (by Transvalor). Used thermophysical properties were generated by JMATPro software. The evolution of microstructure during quenching and resulting hardness were simulated for AISI 4130, and AISI 4140 steel grades. The cooling rates at different positions in the Jominy bar were determined by simulation and compared to experimental. After verification and validation, the FEA simulation 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 allowing us to predict structure and properties in inline quenched continuously cast bar having different diameters.

An attempt was made to characterize microstructure, mechanical properties and cleanliness of continuous cast as rolled billets versus microstructure, mechanical properties and cleanliness of the forging in normalized condition, upset forged from AISI 41B30 modified chemistry billets. Two forgings were compared, one in as forged condition and one in normalized or heat treated condition. Upsets were produced by upsetting only one end of the billet by hydraulic press. Samples from cold portion of the forgings, near the flange location and from flanges were taken and examined. Results of microstructure, mechanical properties and hardness are presented. Normalizing cycle did not improve mechanical and impact properties. Low impact and ductile properties are results of Widmanstätten structure and continue to be present in the final product. Low impact and ductile properties of this structure might not be the best solution for dynamically loaded parts.

The paper considers a process of induction heating of metallic billets prior to hot forming and heat treatment. The main goal of the presented research is a development of novel subject-oriented computer modeling strategy to optimize various induction heating operations using real-life quality criteria. Intricacies of interrelated nature of electromagnetic, temperature and thermal stresses fields during induction heating of metallic billets will be discussed. The model has an interface adapted to optimization procedures. Optimization of temperature patterns is solved using unique alternative optimization method. Computational results for optimal heating of steel cylindrical billets are shown as examples of practical applications of this modeling technology.