The influence of the shielding gas type and mass flow on the melt zone in the surface treatment of 1010 steel using continuous-wave high-power CO₂and Nd:YAG lasers

In studying the surface laser processing techniques several important factors have been the focus of this investigation. The effects of laser scanning speed, mass flow and type of shielding gas on the melt depth of 1/4" thick 1010 steel have been studied in this project. In agreement with previous works, increasing scanning speed showed a decrease in the depth of the melt zone in the process. The next factor, the shielding gas mass flow effect, is the least investigated factor in the recent literature. Using a depth prediction method employed by Steen-Eherhad, we have established a corresponding mathematical formula for a 2000W laser power at a constant 1500mm/min scanning speed. Speed effect has a very good agreement with theoretical result derived by Steen-Ehrhard. In analyzing the melt depth data a first order linear regression was applied and in most cases this regression shows a good correlation between melt depth and mass flow of shielding gases. Our data acquired by measuring plasma size also indicates that the plasma size does not have a correlation with the melt zone depth.