Parametric study on laser nitriding of 1.5919 steel

In order to determine the influence of operational parameters on the effectiveness of surface nitriding using a high power continuous CO2 laser source, the W.Nr. 1.5919 steel was selected as model material since its metallurgical response during conventional nitriding has been widely studied. Particular parameters studied were: the laser beam power (P), the laser beam scanning velocity (V), the number of successive passes (N) and the way of nitrogen supply to the surface under treatment. The process evaluation was performed by extensive microstructural observations and microhardness measurements of the treated zone. Optimal combinations of operational parameters resulted in successful nitriding of a significantly thick surface zone with microhardness of 920–970 HV0.2, free of cracks, pores or melting evidence, followed by a transition zone of decreasing microhardness.