Static and fatigue behavior of laser welded additively manufactured 17-4 PH steel plates

Industry continuously demands for advanced materials delivering high strength, high fatigue resistance and lightweight properties. Additive Manufacturing (AM) technologies allow for the fabrication of lightweight components with optimized sizes and shapes without the need for joining or welding operations. However, almost every AM process for metals currently allows to produce relatively small parts due to the small sizes of the building chambers and/or to the severe deformations occurring during building. This work aims at evaluating the potential usage of laser welding to join AM parts so as to obtain larger products, thus circumventing this nowadays existent limitation of AM. The work reports the experimental campaign of static and fatigue tests on specimens cut out from laser welded joints made of AM 17-4 PH steel plates. Particularly, Selective Lase Melting (SLM) process was adopted to manufacture 3 mm thick plates, subsequently welded by laser, cut in specimens and tested under static and fatigue loads. Fatigue performances of laser welded AM specimens demonstrated that such a manufacturing procedure is very promising and further developments along this line of research are currently in progress.