Laser welding of thick section of low alloyed steel

摘要

The laser welding process is gaining ever grooving attention. It has been found to be of particular interest in welding of automotive applications, where lasers have so far mostly been used for welding of thin sheet. A new generation of high power lasers has entered the market during the last couple of years. The availability of higher power brings the laser welding also to applications of thick section welding. Compared to old generation lasers, like CO2 laser, new lasers have better absorption, better beam quality and higher electrical efficiency. They are not as sensitive to metal vapor on top of keyhole like CO2 laser in respect of process stability and resulting weld shape. This study investigates the performance, potential and problems of the deep penetration laser welding of S355 EN 10025 structural steel. Thicknesses up to 25 mm have been show potential in welding with laser power 15-30 kW. Visual examinations of the macrographs and hardness tests of all welded specimens were made. First versions of quality windows were drawn based on the results of the experiments.