Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Laser beam welding of additive manufactured components: Applicability of existing valuation regulations
    ( 2022)
    Jokisch, T.
    ;
    Gook, Sergej
    ;
    Marko, Angelina
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    Üstündağ, Ömer
    ;
    Gumenyuk, A.
    ;
    Rethmeier, Michael
    With additive manufacturing in the powder bed, the component size is limited by the installation space. Joint welding of additively manufactured parts offers a possibility to remove this size limitation. However, due to the specific stress and microstructure state in the additively built material, it is unclear to what extent existing evaluation rules of joint welding are also suitable for welds on additive components. This is investigated using laser beam welding of additively manufactured pipe joints. The welds are evaluated by means of visual inspection, metallographic examinations as well as computed tomography. The types of defects found are comparable to conventional components. This is an indicator that existing evaluation regulations also map the possible defects occurring for weld seams on additive components.
  • Publication
    Comparison between GTA and laser beam welding of 9% Ni steel for critical cryogenic applications
    ( 2018)
    El-Batahgy, A-M.
    ;
    Gumenyuk, A.
    ;
    Gook, S.
    ;
    Rethmeier, M.
    In comparison with GTA welded joints, higher tensile strength comparable to that of the base metal was obtained for laser beam welded joints due to fine martensitic microstructure. Impact fracture toughness values with much lower mismatching were obtained for laser beam welded joints due to similarity in the microstructures of its weld metal and HAZ. In this case, the lower impact fracture toughness obtained (1.37 J/mm2) was much higher than that of the GTA welded joints (0.78 J/mm2), which was very close to the specified minimum value (>0.75 J/mm2). In contrast to other research works, the overall tensile and impact properties are influenced not only by the fusion zone microstructure but also by the size of its hardened area as well as the degree of its mechanical mismatching, as a function of the welding process. A better combination of tensile strength and impact toughness of the concerned steel welded joints is assured by autogenous laser beam welding process.