The paper presents a model of phenomena occurring during the induction hardening of carbon steel. The mutual influences of the electromagnetic field, temperature field and phase transitions were taken into account. The electromagnetic field was calculated based on Maxwell's equations, taking into account the changes in conductivity from temperature and magnetic permeability from the temperature and intensity of the magnetic field. The temperature field is described by the diffusion equation, taking into account the heat source from eddy currents. The finite element method was used to solve the field equations. The contents of each phase during heating and cooling were calculated based on the Avrami, Koinstinen and Marburger equations and TTT diagrams.

Keywords: Field coupling, Induction hardening, Heat treatment, Finite element method, Modeling