Laser assisted turning (LAT) is using a laser beam to preheat the workpiece before turning [1]. In order to verify the influences of parameters on surface layer after laser heating 9XC hardened alloy steel (62 HRC hardness), various parameters such as: laser power, distance of laser tip to the workpiece, laser position, cutting speed and feed rate had been sellected using Taguchi experimental method. The results shows that the laser power is strongly affect to the surface layer of 91,27 % comparing with the others of laser source’s pararmeters. Besides that the effect of cutting parameters on surface layer was 95,69 % of cutting speed and 4,31 % of feed rate, respectively. From experimetal results, a formula for the structural depth of surface layer as a function of laser power and cutting speed had also been constructed. Results confirmed that surface layer shows a minor change with increasing of cutting speed, whereas laser power demonstrates a significant effect on surface layer.
