Study of heat-affected zone (HAZ) caused by cutting of Thin Ti-CP Sheet via CW CO2 Laser

Laser cutting is one of the modern methods for cutting. In this method heat affected zone width and microstructure changes as a result and also sheet deformation are very low in comparison to other thermal methods and a fine cut is the result. The control of heat-affected zone (HAZ) during laser cutting of titanium sheets due to low thermal conductivity and high tendency to chemical reaction is of great importance. In this paper, the effect of some of the most important laser cutting parameters, including the type of assistant inert gas, stand-off distance, cutting speed and power on HAZ width was assessed in CW CO2 laser cutting of Ti-CP sheets, using Taguchi L16 orthogonal array. Metallography of the cut samples, effects of cutting parameters and optimal conditions of cutting were investigated. Taking into consideration the test results, it is suggested to select the highest possible cutting speed for thin Ti-CP sheets and provide the required severance energy by controlling the laser power. The use of helium instead of argon also showed a significant impact on the reduction of HAZ width. Finally, microstructure and hardness changes are presented.