Product Code: ICA11_106

Study on Striation Generation Process During Laser Cutting of Steel
Authors:
Koji Hirano, PIMM Laboratory, Nippon Steel Corporation; Futtsu-City Chiba Japan
Remy Fabbro, Nippon Steal Corporation; Paris France
Presented at ICALEO 2011

We have investigated striation generation process during laser cutting of steel with inert gas. Our experimental analysis of hydrodynamics of melt layer on kerf front has brought new insights into the mechanisms of this process, which have been left unknown for a long time in spite of the significance for industrial applications. The results have shown that the melt flow can split into two flows that can be independent, one being located along the central part and the other one along the side regions of the kerf front. The observed regimes of instabilities of the two flows depend on cutting velocity in different ways. This newly revealed 3D structure of the melt flow suggests that striations left on kerf sides can be generally divided into the upper and lower parts, which are controlled by the melt flow on the side and central parts of the kerf front, respectively. These results allow us to discuss the interesting topic of the difference in surface quality observed in cutting experiments with 1 micron and 10 micron laser beams.