Laser Hardening Modelling: Comparison between Induction and Laser Hardening on a Mechanical Part

In this paper a numerical model for simulation of hypo eutectoid steel laser hardening process is presented. The Finite Difference Method (FDM) was used to solve the heat transfer and the carbon diffusion equations for defined workpiece geometry. The model is able to predict the thermal cycle into the target material, the phase transformations and the resulting microstructures according to the laser process parameters, the workpiece dimensions and the physical properties of the workpiece. The effects of the overlapping laser beam tracks on the resulting microstructures can be also considered. Besides the original material microstructure is taken into account in the simulation process by means of a digitized photomicrograph in which the initial ferrite-pearlite distribution is acquired. Several experimental tests were then carried out on a torque limiter hub made of C43 UNI 7847 and laser hardened by means of CO2 laser or induction source. The comparisons were made between the geometry of the two different surface hardenings and the hardness profiles.