TY - JOUR A1 - Raute, Julius A1 - Schmidt, Jonathan A1 - Jokisch, Torsten A1 - Biegler, Max A1 - Rethmeier, Michael T1 - Prozessführung und erreichbare Nahtqualitäten: Elektronenstrahlschweißen von additiv gefertigtem Inconel 939 N2 - Additive Fertigungstechnologien wie das Laser-Pulverbett-Verfahren bieten großes Potenzial für die Fertigung von Neu und Ersatzteilen für stationäre Gasturbinen aus Nickelsuperlegierungen wie Inconel 939 (IN939). Um die Integration in bestehende Baugruppen zu ermöglichen und Bauraumbeschränkungen zu überwinden, muss die Prozesskette der additiven Fertigung um geeignete Fügetechniken erweitert werden. Die vorliegende Arbeit beschäftigt sich daher mit dem Schweißen von Inconel 939. Hierbei werden Bleche aus Gussmaterial und der additiven Herstellung mittels Laser im Pulverbett beim Elektronenstrahlschweißen verglichen. Im Fokus der Untersuchung stehen die erreichbare Nahtqualität im Hinblick auf geometrische Unregelmäßigkeiten sowie innere Defekte in Form von Mikrorissen in der Wärmeeinflusszone. Bei der Auswertung der geschweißten Proben zeigen sich keine Unterschiede in der Ausbildung der Nahtform zwischen dem additiv gefertigten Material und dem Gusswerkstoff. Für beide Materialien ließ sich bei hohen Vorschubgeschwindigkeiten von 20 mm/s die höchste Bewertungsgruppe für Strahlgeschweißte Nähte nach DIN EN ISO 13919-1 erreichen. Unabhängig von der Herstellungsart zeigen beide Materialien eine Zunahme der Rissneigung mit steigendem Vorschub. Das Material aus der additiven Herstellung weist aufgrund seiner Mikrostruktur insgesamt jedoch deutlich weniger Mikrorisse auf, was Potenzial für die Anwendung in der Praxis eröffnet. KW - Elektronenstrahlschweißen KW - PBF-LB/M KW - Inconell939 PY - 2025 UR - https://www.schweissenundschneiden.de/artikel/prozessfuehrung-und-erreichbare-naht-qualitaeten-elektronenstrahlschweissen-von-additiv-gefertigtem-inconel-939 DO - https://doi.org/10.53192/SUS202510 VL - 77 IS - 10 SP - 2 EP - 8 PB - DVS Media Verlag CY - Eltville am Rhein, Deutschland AN - OPUS4-64300 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raute, Julius A1 - Beret, Alexander A1 - Biegler, Max A1 - Rethmeier, Michael T1 - Ökobilanzierung in der additiven Fertigung – Laser- vs. Elektronenstrahl N2 - Die additive Fertigung gewinnt für industrielle Anwendungen zunehmend an Bedeutung. In diesem Zusammenhang sind Verfahren der Directed Energy Deposition (DED) besonders gefragt, um hohe Aufbauraten zu erreichen. Neben den bekannten laserstrahlbasierten Verfahren hat auch der Elektronenstrahl die industrielle Marktreife erreicht. Das Wire Electron Beam Additive Manufacturing bietet zum Beispiel Vorteile bei der Verarbeitung von Kupferwerkstoffen. In der Literatur wird die höhere Energieeffizienz und die daraus resultierende Verbesserung der CO2-Bilanz des Elektronenstrahls hervorgehoben. Es fehlt jedoch an praktischen Studien mit Messdaten, um das Potenzial der Technologie zu quantifizieren. In dieser Arbeit wird eine vergleichende Ökobilanz zwischen der additiven Fertigung mit Draht und Elektronenstrahl (DED-EB) und der additiven Fertigung mit Laserstrahl und Pulver (DED-LB) durchgeführt. Dazu werden die Ressourcen für die Herstellung ermittelt, ein Testbauteil mit beiden Verfahren hergestellt und der gesamte Energieverbrauch gemessen. Die Umweltauswirkungen werden dann mit den Faktoren Treibhauspotenzial (GWP100), Ozonbildungspotenzial (POCP), Versauerungspotenzial (AP), Eutrophierungspotenzial (EP) abgeschätzt. Es zeigt sich, dass das Wire Electron Beam Additive Manufacturing durch einen deutlich geringeren Energiebedarf gekennzeichnet ist. Darüber hinaus gewährleistet die Verwendung von Draht eine größere Ressourceneffizienz, was zu insgesamt besseren Ökobilanzergebnissen führt. KW - Ökobilanzierung (LCA) KW - Additive Fertigung KW - Directed Energy Deposition KW - Kupfer KW - Wire Electron Beam Additive Manufacturing PY - 2024 SP - 26 EP - 32 AN - OPUS4-62234 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fabry, Çağtay A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Arc-sidewall-attaching-driven control of swing arc motion in narrow gap GMAW N2 - A novel, event-driven approach to controlling the weaving motion in swing arc narrow gap GMAW is presented in this study. The control method is based on independently detecting the arc attachment event at each sidewall of the narrow groove to adjust the weaving motion in real time. Previous arc sensing approaches for swing arc principles are based on evaluating and comparing arc sensor readings collected during the dwell periods at each sidewall. Not only does this require the torch to be positioned at the groove centre and the arc motion to be symmetric, but previous methods have also been shown to rely on complex parametrization of control parameters. The newly presented approach is based on the real-time monitoring of the welding current progression during the approach of the arc towards the sidewall of the groove independently on each side. As soon as the arc attachment at the sidewall is detected based on a characteristic rise in the current signal, the weaving motion is stopped. For reference experiments in a 21-mm wide groove, the weaving angle amplitude is controlled and limited to 50° on both sides individually, resulting in stable process conditions and uniform sidewall fusion. It is further shown that the newly developed control method can successfully be applied to groove widths of 18 mm and 24 mm without reconfiguration of the control parameters, highlighting the flexibility of the approach. KW - Gas metal arc welding KW - Narrow gap KW - Arc sensor KW - Control PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647640 DO - https://doi.org/10.1007/s40194-025-02238-5 SN - 0043-2288 SP - 1 EP - 11 PB - Springer Science and Business Media LLC AN - OPUS4-64764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rethmeier, Michael A1 - Gumenyuk, Andrey A1 - Quiroz Penaranda, Vanessa T1 - Investigation on laser beam welding of high-manganese austenitic and austenitic-ferritic stainless steels PY - 2012 SN - 0005-111x SN - 0005-2302 VL - 1 IS - 705 SP - 12 EP - 17 CY - Kiev, Ukraine AN - OPUS4-27209 LA - rus AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Quiroz Penaranda, Vanessa A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Investigation of the hot cracking susceptibility of laser welds with the controlled tensile weldability test N2 - Due to significant developments over the last decades, laser beam welding has become a well-established industrial process offering high processing speeds and causing low component distortions. But an important issue currently preventing its intense use, especially in the energy or plant construction sector where high alloy steels are applied, concerns hot crack formation. Although considerable advances in understanding hot cracking mechanisms have been made, most of the known influencing factors are metallurgical in character. The thermo-mechanical effects are barely considered or quantified. Up to the present, there exist numerous hot cracking tests that were however conceived for welding methods other than laser beam welding. Considering the special features of the laser welding process, such as high cooling rates and the narrow process zone, results obtained with other welding techniques and test procedures cannot be transferred to laser beam welding. In this study, the laser beam weldability of various stainless steels was examined in terms of their susceptibility to hot cracking by means of the controlled tensile weldability test, which was proven to be suitable for use in conjunction with CO2 laser welding. This test allows the application of tensile strain at a variable fixed cross-head speed transverse to the welding direction. Full and partial penetration bead-on-plate welds were produced. In a first attempt to determine the impact of the applied external strain on the local transient strains and strain rates near the weld pool, an optical system was used to measure the backside surface of partial penetration welds. The results showed the influence of the strain and the strain rates on hot crack formation. Furthermore, a classification of the studied austenitic, duplex and ferritic stainless steels according to the established test criteria (critical strain and cross-head speed) was conducted. KW - Laser beam welding KW - CO2 laser KW - Hot cracking KW - Stainless steels KW - Critical strains KW - Strain rates KW - Hot cracking test KW - Controlled tensile weldability test PY - 2012 DO - https://doi.org/10.1177/0309324712462120 SN - 0309-3247 SN - 2041-3130 VL - 47 IS - 8 SP - 587 EP - 599 PB - Sage CY - London AN - OPUS4-27281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, André A1 - Avilov, Vjaceslav A1 - Gumenyuk, Andrey A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - High power laser beam welding of thick-walled ferromagnetic steels with electromagnetic weld pool support N2 - The paper describes an experimental investigation of high power laser beam welding with an electromagnetic weld pool support for up to 20 mm thick plates made of duplex steel (AISI 2205) and mild steel (S235JR). The results of the welding tests show a successful application of this technology at ferromagnetic metals. Irregular sagging was suppressed successfully. An ac-power of less than 2 kW at oscillation frequencies between 800 Hz and 1.7 kHz is necessary for a full compasation of the hydrostatic pressure. Thus, it was demonstrated that the electromagnetic weld pool support is not only limited to non-ferromagnetic metals like austenitic steels. For future studies with duplex steel, the use of filler material has to take into account with regard to the balance of the mixed austenitic and ferritic phases. KW - Laser beam welding KW - Thick-walled steel KW - Ferromagnetic steel KW - Weld pool support PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377593 DO - https://doi.org/10.1016/j.phpro.2016.08.038 SN - 1875-3892 VL - 83 SP - 362 EP - 372 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-37759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schempp, Philipp A1 - Cross, Carl Edward A1 - Schwenk, Christopher A1 - Rethmeier, Michael T1 - Influence of Ti and B additions on grain size and weldability of aluminium alloy 6082 N2 - Grain refinement is an important possibility to enhance the weldability of aluminium weld metal that is usually defined by its susceptibility to solidification cracking. In this study, grain refinement was achieved through the addition of commercial grain refiner containing titanium and boron to the GTA weld metal of aluminium alloy 6082. The weld metal mean grain size could be reduced significantly from about 70 µm to a saturated size of 21 µm with a change in grain shape from columnar to equiaxed. The grain refinement prevented the formation of centreline solidification cracking that was present only in welds with unrefined grain structure. A variation of torch speed led to a strong change of solidification parameters such as cooling rate that was measured in the weld metal and the corresponding solidification rate and thermal gradient. The ratio thermal gradient/growth rate (G/R) decreased from 50 K s/mm² (high torch speed) to 10 K s/mm² (low torch speed). However, the variation of torch speed did not change the tendency for solidification cracking. The microstructure of unrefined and completely refined weld metal was compared. The observed change in size and distribution of the interdendritic phases was related to the change in susceptibility to solidification cracking. KW - Aluminium KW - WIG-Schweißen KW - Kornfeinung KW - Schweißeignung KW - Heißrisse KW - Aluminium alloy KW - Solidification cracking KW - Weldability KW - GTA welding PY - 2012 SN - 0043-2288 SN - 1878-6669 VL - 56 IS - 09/10 SP - 95 EP - 104 PB - Springer CY - Oxford AN - OPUS4-26992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Vinzenz A1 - Klement, Oliver A1 - Sander, Steffen A1 - Biegler, Max A1 - Rethmeier, Michael T1 - Recycling of Stainless Steel Milling Chips for Additive Manufacturing: A Three-Stage Comminution Approach Using a Fine Impact Mill N2 - The production of conventional metal powders for additive manufacturing process is energy intensive and costly. This study introduces a sustainable alternative by recycling stainless steel milling chips as feedstock for laser-powder directed energy deposition. The recycling process employs a three-stage mechanical comminution method utilizing a fine impact mill UPZ100 from Hosokawa Alpine AG. Characterization of the resulting powders is conducted through particle morphology analysis, flowability tests, and mechanical property assessments. The chip-derived powders exhibit comparable aspect ratios and sphericity to conventional water atomized powders, though with reduced flowability due to a pronounced fine fraction content. Elevated levels of oxides are observed, leading to the formation of an oxide layer on specimen blocks, without impairing the mechanical properties. Analyses of porosity, microstructure, and hardness indicate no significant differences when compared to conventional powders from water or gas atomization. This recycling approach not only mitigates waste but also enhances the potential for a circular and sustainable manufacturing process in the additive manufacturing industry and beyond. KW - Directed Energy Deposition KW - Recycling KW - Stainless steel KW - Comminution KW - Powder characteristics PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652037 DO - https://doi.org/10.1088/1757-899X/1332/1/012014 SN - 1757-8981 VL - 1332 IS - 1 SP - 1 EP - 7 PB - IOP Publishing AN - OPUS4-65203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schempp, Philipp A1 - Cross, C.E. A1 - Pittner, Andreas A1 - Oder, Gabriele A1 - Neumann, R. S. A1 - Rooch, Heidemarie A1 - Dörfel, Ilona A1 - Österle, Werner A1 - Rethmeier, Michael T1 - Solidification of GTA aluminium weld metal: Part I - Grain morphology dependent upon alloy composition and grain refiner content N2 - The solidification conditions during welding strongly influence the weid metal microstructure and mechanical properties of a weid. In the first part of this study, the grain morphology of gas tungsten arc (GTA) bead-on-plate welds was investigated for the aluminum Alloys 1050A (Al 99.5), 6082 (Al SifMgMn), and 5083 (AI Mg4.5Mn0.7). The experiments revealed that increasing welding speed and alloy content allow the growth of small, equiaxed grains, particularly in the weid center. Furthermore, increasing grain refiner additions led to a Strong reduction of the weid metal mean grain size and hence facilitated the columnar to equiaxed transition (CET). In addition, wavelength dispersive X-ray spectroscopy (WDS) and transmission electron microscopy (TEM) analysis revealed in the weid metal TiB2 particles that were surrounded by Al3Ti. This suggests the duplex nucleation theory for nucleation of aluminum grains in GTA weid metal. KW - Aluminium KW - Gas tungsten arc welding (GTAW) KW - Grain refinement KW - Columnar to equiaxed transition (CET) KW - Epitaxial nucleation KW - Duplex nucleation theory PY - 2014 SN - 0043-2296 SN - 0096-7629 VL - 93 SP - 53-s EP - 59-s PB - American Welding Society CY - New York, NY AN - OPUS4-30413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marquardt, R. A1 - Gook, S. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Handgeführtes Laserstrahlschweissen am T-Stoss eines niedrig legierten Stahls N2 - Das handgeführte Laserstrahlschweißen gewinnt in der Industrie zunehmend an Bedeutung, da die hohe Produktivität und die einfache Handhabung Unternehmen wirtschaftliche Vorteile bieten. Derzeit ist der Einsatz in der Industrie jedoch auf Teile mit ästhetischen Anforderungen beschränkt, die häufig aus hochlegiertem Stahl bestehen. Um das Handschweißen mit Laserstrahl auch für Bauteile aus kostengünstigen Stähle mit guten mechanischen Eigenschaften einsetzen zu können, untersucht diese Studie den Einfluss des Schutzgases auf die Porosität am mikrolegierten Stahl HX340LAD mit einer Dicke von 1,5 mm. Getestet wurden die Gase Argon, Stickstoff, CO2 sowie Mischungen aus Argon und CO2 an T-Stöße mit Zusatzdraht. Die Qualifizierung der Porosität erfolgte gemäß DIN EN ISO 13919-1 an Querschliffen als auch mittels Röntgenuntersuchung. Die Ergebnisse zeigen, dass für diesen Stahl die Bewertungsgruppe B mittels CO2 als Schutzgas erreicht werden kann. Stickstoff führt zu Gruppe C, Argon zu D. KW - Handgeführtes Laserstrahlschweißen, HHLW, Stahl, Laser KW - HHLW KW - Stahl KW - Laser PY - 2025 SP - 22 EP - 25 PB - Schweizerischer Verein für Schweisstechnik SVS AN - OPUS4-65041 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -