The bachelor thesis deals with the porosity of laser surfacing welds on surfaces of nitrided tools. The thesis includes the survey of literature on the subject of laser welding, weld surfacing, and eliminating porosity in the weld surfacing of nitrided surfaces. A plan of experiments in weld surfacing is made, demonstrating how the use of filler materials containing various amounts of titanium, should prevent porosity. Macro etch specimens were prepared, and an optic microscopy, as well as SEM microscopy, and analysis of chemical structure were performed upon them. We found out that the amount of porosity is influenced by the melt depth of the base material and the amount of titanium in the filler material. The porosity in the weld was reduced under 1% of the whole surface of the weld, with 5,87% of titanium in the filler wire. Results demonstrate that with an adequate choice of parameters and an adequate technique of welding, similar results can be achieved with more than 0.6% of titanium in the filler material.
|
