Experimental Researches of Turning Hardened 9CrSi Alloy Tool Steel with Laser-Assisted Machining

Abstract

In this study, in order to verify the influences of various parameters such as laser power, laser spot diameter on the workpiece, laser position, laser head speed, and feed rate on the depth of heat-affected zone (HAZ) after laser heating hardened 9CrSi alloy steel (62 HRC hardness) before turning process, Taguchi experimental method had been applied. The experimental results show that the laser power and laser head speed strongly affect the depth of HAZ comparing with the others of laser source’s parameters. Specifically, the results of the ANOVA for the depth of HAZ revealed that the laser power at static state and laser head speed at dynamic state made the highest contribution of 91.27 and 95,69% to the overall performance, respectively. This study then analyzes the effects of parameters such as laser power, cutting speeds, feed rate, and cutting depth on the depth of HAZ and microhardness of the workpiece after turning hardened 9CrSi alloy tool steel with laser-assisted machining. The analysis of the experimental results shows that if the cutting depth and cutting speed is from and over 0.15 mm, and 71 m/min, respectively, leads to the microstructure and microhardness of the workpiece after machining are significantly unaffected. Finally, the experimental surface responses of surface roughness and cutting force are obtained based on the reasonable zone of input parameters. The ANOVA results also confirmed that laser power made the highest contribution to the surface roughness and the feed rate contribute the major effect to the cutting force of 69.4 and 63.56%, respectively.