Numerical simulation of steel heat treatments

The main aim of this thesis is to simulate solid state metallurgical processes like quenching and tempering in steels. The thesis consists of two parts. In the first part steel hardenability by end quenching test (Jominy test) was simulated and in the second part a quenching and self-tempering process was simulated. The steel used for the first simulation is C45 which is medium carbon steel with carbon content of about 0.5%. Jominy test is used to check hardenability of steel using a standard specimen of diameter 25 mm and length 100 mm. The specimen is heated at around 900 [deg C] and then quenched at one end using water. The duration of test is about 2000 seconds. After which all the phases are detected and plotted against time. Finally, hardness of steel is calculated. Due to quenching with water at one end of specimen almost all of the austenite is transformed into martensite due to extremely high value of heat coefficient. On top of martensite there is a small portion where bainite is dominant while everywhere else its pearlite. In the quenching and self-tempering simulation, a specimen of 32 mm diameter is heated to around 950 [deg C] and then initially quenched using water until surface temperature becomes less than starting temperature of martensite. Then the specimen was left for slow cooling in the air. Since the core is at higher temperature heat is transferred to the surface and increase in surface temperature is observed. This cause self-tempering of steel. The method is useful in making steel rebars which have many useful applications in industry. Results were compared with those given in literature.