The lack of practical information regarding the kinetics of a thermal process can be compensated by estimating the kinetic parameters of the process. Using the methodology imposed by Baram, as well as to one resulted form the use of the solution to the Fick’s differential equation, through a minimum number of experiences, can be obtained sufficient information to estimate the process’ average speed, its activation energy, the diffusion coefficient, etc., and forecast the saturation effects in conditions different from those used for experiments to obtain preliminary information. This paper presents the experimental results obtained during the nitriding of pure technical iron and respectively of a nitraloy type alloyed steel for improvement, regarding the kinetic of the nitrided layers’ growth and starting from this results, the calculated values of the of the kinetic parameters, respectively the forecasted values of the kinetics in conditions different from those effectively used during experiments.