The advantage of selective laser melting (SLM) is its high accuracy and geometrical flexibility.\nBecause the maximum size of the components is limited by the process chamber, possibilities must be\nfound to combine several parts manufactured by SLM. An application where this is necessary, is,\nfor example, the components of gas turbines, such as burners or oil return pipes, and inserts, which can\nbe joined by circumferential welds. However, only a few investigations to date have been carried out\nfor the welding of components produced by SLM. The object of this paper is, therefore, to investigate\nthe feasibility of laser beam welding for joining SLM tube connections made of nickel-based alloys.\nFor this purpose, SLM-manufactured Inconel 625 and Inconel 718 tubes were welded with a Yb:YAG\ndisk laser and subsequently examined for residual stresses and defects. The results showed that\nthe welds had no significant influence on the residual stresses. A good weld quality could be achieved\nin the seam circumference. However, pores and pore nests were found in the final overlap area,\nwhich meant that no continuous good welding quality could be accomplished. Pore formation was\npresumably caused by capillary instabilities when the laser power was ramped out.
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