The newly developed Nickel-base superalloy G27 with its reduced amount of Cobalt represents an alternative to the widely used WASPALOY. It combines a more ethical composition and a reduction of the price. Another cost reduction can be achieved by a replacement of the widely used casting process with welding. However, the industry remains mostly sceptical about new manufacturing approaches. The aim of this study is the show that both LASER and Keyhole-TIG welding are suitable joining processes to weld smaller parts of this superalloy together. In detail, the core aspect of this work is to examine the optimal welding parameters for both processes to achieve the most beneficial weld geometry.

To carry out the results a design of experiments was used together with a linear regression model. The design of experiments was fed with values obtained in a metallurgical laboratory. With the software IMAGEJ, the specimens’ porosities were assessed and with MODDE, the plots of the results and their statistical relevance were appraised. It was found out that both processes struggled to match the welding geometry requirements of the underlying industrial standard from the American Welding Society. LASER welding often exhibited narrow weld width in the middle of the hour-glass-shaped welds and Keyhole-TIG showed too much undercut. Still, the results pointed out that for LASER a high heat input is recommendedwhile for Keyhole-TIG it is a low heat input. For the undercut problem also conventional TIG might be a solution.