Experiments on convection in laser-melted pools

Georges Caillibotte; Didier Kechemair; Lilian Sabatier

doi:10.1117/12.46889

1 October 1991 Experiments on convection in laser-melted pools

Georges Caillibotte, Didier Kechemair, Lilian Sabatier

Proceedings Volume 1502, Industrial and Scientific Uses of High-Power Lasers; (1991) https://doi.org/10.1117/12.46889
Event: ECO4 (The Hague '91), 1991, The Hague, Netherlands

Abstract

High-power CO2 cw lasers proved to be very efficient in surface treatment of metallic materials in order to improve wear or fatigue resistance of workpieces. In the case of surface treatments which involve a molten zone, it is necessary to improve existing knowledge on convection which can take place inside the metallic bath during laser-material interaction. As a matter of fact, metallurgical investigations showed that this convection influences the homogenization and the structure of the metal specimen. It has been pointed out by some researchers that these movements are generated by high-temperature gradients which produce surface tension variations within the liquid surface. This kind of flow is generally called Marangoni Convection. A method which allows the measurement of some particle velocities on the pool surface is described. A CCD camera was used to estimate surface temperatures and a high-speed video camera allowed the analysis of the velocity fields. The first experiments showed that the order of magnitude of these velocities is typically about a few tens of centimeters per second in the case od cast-iron surface treatment. The scanning speed was about one centimeter per second with a 10 kW/cm2 shaped beam originating at a 6 mods UTIL laser.

Citation Download Citation

Georges Caillibotte, Didier Kechemair, and Lilian Sabatier "Experiments on convection in laser-melted pools", Proc. SPIE 1502, Industrial and Scientific Uses of High-Power Lasers, (1 October 1991); https://doi.org/10.1117/12.46889

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