Laser welding energy redistribution and weld geometry

Sammanfattning: Over the past few years laser welding has developed into a process which has a wide range of application over a number of industries. Industrial growth in this area has been stimulated by improvements in production rates and quality but technologically the process is still not fully understood. This work aims to contribute to the understanding of deep penetration laser welding with emphasis on energy redistribution and weld geometry. The seven papers which make up the thesis investigate various aspects of the absorption and redistribution of energy during laser welding. Theoretical and experimental methods have been used to analyze the effects of process parameters on the geometry of the resultant welds. Considerable success has been achieved in matching theoretical predictions to actual results. This work has helped to clarify a number of features of the laser welding process including the following; 1. The effect of process parameters on the efficiency of laser welding. 2. The mechanisms of energy absorption which result in a weld. 3. The effect of an increased external pressure on the laser-material interaction. 4. The effect of thermocapillary flow and how it can be taken advantage of in industrial applications.