TY - JOUR A1 - Rethmeier, Michael A1 - Gumenyuk, Andrey A1 - Bachmann, Marcel T1 - High-power laser beam welding for thick section steels – new perspectives using electromagnetic systems JF - Science and Technology of Welding and Joining N2 - In recent years, it was shown that the introduction of additional oscillating and permanent magnetic fields to laser beam and laser-arc hybrid welding can bring several beneficial effects. Examples are a contactless weld pool support for metals of high thickness suffering from severe drop-out when being welded conventionally or an enhanced stirring to improve the mixing of added filler material in the depth of the weld pool to guarantee homogeneous resulting mechanical properties of the weld. The latest research results show the applicability to various metal types over a wide range of thicknesses and welding conditions. The observations made were demonstrated in numerous experimental studies and a deep understanding of the interaction of the underlying physical mechanisms was extracted from numerical calculations. KW - Laser beam welding KW - Numerical simulations KW - Electromagnetic support PY - 2021 DO - https://doi.org/10.1080/13621718.2021.1999763 VL - 27 IS - 1 SP - 43 EP - 51 PB - Taylor & Francis Group AN - OPUS4-53970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gumenyuk, Andrey A1 - Straße, Anne A1 - Rethmeier, Michael T1 - Improvement of the mechanical properties and corrosion resistance of laser welds on thick duplex plates by laser cladded buttering N2 - Because of its excellent corrosion resistance, high tensile strength and high ductility, duplex stainless steel 2205 offers many areas of application. Though laser beam welding accompanied by high cooling rates, duplex steels tend to perform higher ferrite contents in weld metal as the base metal, which leads to a reduction of ductility and corrosion resistance of the weld joint. To overcome this problem, a solution, based on buttering the plate edges by laser metal deposition (LMD) with material containing higher Ni concentrations prior to laser welding was suggested. In this context different process parameters for LMD and different mixtures of duplex and nickel powder, were investigated. In a second step the possibility of welding those edges defect free while achieving balanced austenite-ferrite ratio was verified with metallographic analysis, Electron Backscatter Diffraction (EBSD) and impact testing according to Charpy. The improved corrosion resistance was observed with ASTM G48 standard test method. T2 - X International Conference «Beam Technologies in Welding and Materials Processing» CY - Odessa, Ukraine DA - 7.09.2021 KW - Laser beam welding KW - Laser metal deposition KW - Duplex steels PY - 2021 AN - OPUS4-53568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Churiaque, C. A1 - Sanchez-Amaya, J.M. A1 - Üstündag, Ömer A1 - Porrua-Lara, M. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Improvements of hybrid laser arc welding for shipbuilding T-joints with 2F position of 8 mm thick steel JF - Optics and Laser Technology N2 - the joints throughout the structure. The flat units are constituted by butt welded flat plates, on which longitudinal T-welded reinforcements are placed to rigidize the structure. Among the different welding technologies, Hybrid Laser Arc Welding (HLAW) is becoming a mature process, profitable and highly productive. In addition, more innovative welding equipment are being developed nowadays, offering greater work flexibility, and raising expectations of achieving better quality, and economic viability. Another key point of HLAW to keep in mind is that structural distortions are reduced, resulting in decreasing the cost and time of straightening work. In the present contribution, the influence of HLAW parameters on the quality of fillet joints of naval steel has been analysed. Experimental HLAW tests were performed with a high power disk laser to join EH36 naval steel plates, with a T configuration. The influence of different processing parameters has been analysed, as the laser power, welding speed, wire feed rate and the configuration of the HLAW processes (including head angle and laser/arc leading process). In addition, FEM simulations were carried out in order to estimate residual stresses and distortion of welded part. The distortion values provided by FEM presented excellent agreement with the measured experimental results. To evaluate the welds, non destructive tests including X-ray tests, metallographic analysis of cross sections, and microhardness mapping tests were performed. Full penetration 8 mm T welds were obtained for the first time at an industrially applicable 2F position with a reasonable HLAW head angle, in one single step without sealing root, and using zero gap square groove Edge preparation. The present contribution presents welding rates up to 2.2 m/min for 2F T-joints of this steel thickness, a much higher processing velocity than previously reported for industrial applications. KW - Hybrid laser arc welding PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528410 DO - https://doi.org/10.1016/j.optlastec.2021.107284 VL - 143 SP - 1 EP - 20 PB - Elsevier Ltd. AN - OPUS4-52841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Straße, Anne A1 - Gumenyuk, Andrey A1 - Scheuschner, Nils A1 - Altenburg, Simon A1 - Pignatelli, Giuseppe A1 - Gornushkin, Igor B. A1 - Baensch, Franziska A1 - Rethmeier, Michael T1 - In-situ Prozessüberwachung beim Laser-Pulver-Auftragschweißen (LPA) mittels Thermografie, optischer Emissionsspektroskopie (OES) und Schallemissionsanalyse (SEA) T2 - 41. Assistentenseminar der Füge- und Schweißtechnik N2 - Vor allem in den letzten Jahren ist das Interesse der Industrie an der additiven Fertigung deutlich gestiegen. Die Vorteile dieser Verfahren sind zahlreich und ermöglichen eine ressourcenschonende, kundenorientierte Fertigung von Bauteilen, welche zur stetigen Entwicklung neue Anwendungsbereiche und Werkstoffe führen. Aufgrund der steigenden Anwendungsfälle, nimmt auch der Wunsch nach Betriebssicherheit unabhängig von anschließenden kostenintensiven zerstörenden und zerstörungsfreien Prüfverfahren zu. Zu diesem Zweck werden im Rahmen des von der BAM durchgeführten Themenfeldprojektes „Prozessmonitoring in Additive Manufacturing“ verschiedenste Verfahren auf ihre Tauglichkeit für den in-situ Einsatz bei der Prozessüberwachung in der additiven Fertigung untersucht. Hier werden drei dieser in-situ Verfahren, die Thermografie, die optische Emissionsspektroskopie und die Schallmissionsanalyse für den Einsatz beim Laser-Pulver-Auftragschweißen betrachtet. T2 - 41. Assistentenseminar der Füge- und Schweißtechnik CY - Magdeburg, Germany DA - 02.09.2020 KW - Laser-Pulver-Auftragschweißen (LPA) KW - Thermographie KW - Optische Emissionsspektroskopie (OES) KW - Schallemissionsanalyse (SEA) PY - 2021 SN - 978-3-96144-141-9 VL - 370 SP - 132 EP - 140 PB - DVS MEdia CY - Düsseldorf AN - OPUS4-53967 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Influence of an external applied AC magnetic field on the melt pool dynamics at high-power laser beam welding JF - IOP Conference Series: Materials Science and Engineering N2 - The study deals with the determination of the influence of an externally applied oscillating magnetic field on the melt pool dynamics in high power laser beam and hybrid laser arc welding processes. An AC magnet was positioned under the workpiece which is generating an upward directed electromagnetic force to counteract the formation of the droplets. To visualise the melt flow characteristics, several experiments were carried out using a special technique with mild steel from S355J2 with a plate thickness of up to 20 mm and a quartz glass in butt configuration. The profile of the keyhole and the melt flow were recorded with a highspeed camera from the glass side. Additionally, the influence of the magnetic field orientation to the welding direction on the filler material dilution on laser hybrid welding was studied with variating oscillation frequency. The element distribution over the whole seam thickness was measured with X-ray fluorescence (XRF). The oscillation frequency demonstrated a great influence on the melt pool dynamics and the mixing of the elements of the filler wire. The highspeed recordings showed, under the influence of the magnetic field, that the melt is affected under strong vortex at the weld root, which also avoids the formation of droplets. T2 - 18th Nordic Laser Materials Processing Conference (18th NOLAMP) KW - Laser beam welding KW - AC magnetic field KW - Melt pool dynamics KW - Filler wire mixing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539231 DO - https://doi.org/10.1088/1757-899X/1135/1/012017 VL - 1135 IS - 012017 SP - 1 EP - 10 PB - IOP Publishing AN - OPUS4-53923 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Influence of oscillating magnetic field on the keyhole stability in deep penetration laser beam welding JF - Optics and Laser Technology N2 - The stability of the keyhole decreases for deep penetrated high-power laser beam welding. The keyhole tends to collapse with increasing laser power and e.g. keyhole induced porosity can occur. This study deals with the observation of the keyhole during high-power laser beam welding in partial penetration mode by means of a high-speed camera. A butt configuration of 25 mm thick structural steel and transparent quartz glass was used for the experiments. An oscillating magnetic field was applied perpendicular to the welding direction on the root side of the steel plate. The keyhole was highlighted with a coaxial diode laser. It was ascertained that the stability of the keyhole and the weld penetration depth were increased by applying an oscillating magnetic field with an oscillating frequency of 1.2 kHz and a magnetic flux density of 50 mT. KW - Magnetic field KW - Laser beam welding KW - Keyhole stability PY - 2021 DO - https://doi.org/10.1016/j.optlastec.2020.106715 SN - 0030-3992 VL - 135 SP - 106715 PB - Elsevier Ltd. AN - OPUS4-52007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Investigation of the gap bridgeability at high-power laser hybrid welding of plasma-cut thick mild steels with AC magnetic support JF - IOP Journal of Physics: Conference Series N2 - One of the challenges of the high-power hybrid laser welding of thick steels is the sensitivity of the process of the process to manufacturing tolerances. This usually leads to a time-consuming preparation of the welding edges, such as milling. The study deals with the influence of the edge quality of milled and plasma-cut steel made of S355J2 with a wall thickness of 20 mm on the laser hybrid welded seam quality. Furthermore, the gap bridgeability and the tolerances towards edge misalignment was investigated. An AC magnet was used as backing support to prevent sagging and positioned under the workpiece, to generate an upwards directed electromagnetic pressure. The profiles of the edges and the gap on the top and root side were measured using a digital camera. Single-pass laser hybrid welds of plasma-cut edges could be welded using a laser beam power of just 13.7 kW. A gap bridgeability up to 2 mm and misalignment of edges up to 2 mm could be achieved successful. Additionally, the independence of the cutting side and the welding side was shown, so that samples were welded to the opposite side to their cutting. For evaluation of internal defects or irregularities, X-ray images were carried out. Charpy impact strength tests were performed to determine the toughness of the welds. T2 - X International Conference «Beam Technologies & Laser Application» KW - Laser hybrid welding KW - Magnetic bath support KW - Plasma-cut samples KW - Thick plate welding PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539248 DO - https://doi.org/10.1088/1742-6596/2077/1/012007 VL - 2077 IS - 012007 SP - 1 EP - 8 PB - IOP Publishing AN - OPUS4-53924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gumenyuk, Andrey A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Rethmeier, Michael T1 - Investigation of the gap bridgeability at high-power laser hybrid welding of plasma-cut thick mild steels with AC magnetic support N2 - One of the challenges of the high-power hybrid laser welding of thick steels is the sensitivity of the process of the process to manufacturing tolerances. This usually leads to a time-consuming preparation of the welding edges, such as milling. The study deals with the influence of the edge quality of milled and plasma-cut steel made of S355J2 with a wall thickness of 20 mm on the laser hybrid welded seam quality. Furthermore, the gap bridgeability and the tolerances towards edge misalignment was investigated. An AC magnet was used as backing support to prevent sagging and positioned under the workpiece, to generate an upwards directed electromagnetic pressure. The profiles of the edges and the gap on the top and root side were measured using a digital camera. Single-pass laser hybrid welds of plasma-cut edges could be welded using a laser beam power of just 13.7 kW. A gap bridgeability up to 2 mm and misalignment of edges up to 2 mm could be achieved successful. Additionally, the independence of the cutting side and the welding side was shown, so that samples were welded to the opposite side to their cutting. For evaluation of internal defects or irregularities, X-ray images were carried out. Charpy impact strength tests were performed to determine the toughness of the welds. T2 - X International Conference «Beam Technologies in Welding and Materials Processing» CY - Odessa, Ukraine DA - 7.09.2021 KW - Laser beam welding KW - Hybrid laser arc welding KW - Material transport PY - 2021 AN - OPUS4-53569 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jokisch, T. A1 - Gook, S. A1 - Marko, A. A1 - Üstündag, Ömer A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Laserstrahlschweißen additiv gefertigter Bauteile: Einsetzbarkeit bestehender Bewertungsvorschriften JF - Schweißen und Schneiden N2 - Bei der additiven Fertigung im Pulverbett ist die Bauteilgröße durch den Bauraum begrenzt. Das Verbindungsschweißen additiv gefertigter Teile bietet eine Möglichkeit diese Größenbegrenzung aufzuheben. Aufgrund des spezifischen Spannungs- und Gefügezustands im additiv aufgebauten Teil ist jedoch unklar, inwiefern bestehende Bewertungsvorschriften des Verbindungsschweißens auch für Schweißnähte an additiv gefertigten Bauteilen geeignet sind. Dies wird anhand des Laserstrahlschweißens additiv gefertigter Rohrverbindungen untersucht. Die Schweißnähte werden mittels visueller Prüfung, metallografischer Untersuchungen sowie Computertomografie ausgewertet. Die festgestellten Fehlerarten sind vergleichbar zu konventionellen Bauteilen. Dies ist ein Indikator dafür, dass bestehende Bewertungsvorschriften die möglichen auftretenden Defekte auch für Schweißnähte an additiven Bauteilen abbilden. KW - Schweißunregelmäßigkeiten KW - Additive Fertigung KW - Laserstrahlschweißen KW - Schweißeignung PY - 2021 VL - 73 IS - 3 SP - 132 EP - 137 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-53575 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gook, Sergej A1 - Üstündag, Ömer A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Method for defect-free hybrid laser-arc welding of closed circumferential welds JF - Welding and Cutting N2 - This paper presents investigation results of a process for defect-free hybrid laser arc welding (HLAW) of closed circumferential welds. The process aims to avoid weld imperfections in the overlap area of a HLAW circumferential weld. A process control strategy for closing the circumferential weld was developed to achieve a defect-free overlap region by controlling the solidification conditions at the end of the weld. The controlled heat flow is achieved by adjusting the parameters of both welding processes involved, the laser beam as well as gas metal arc welding (GMAW) process. Experimental investigations were carried out on 12 mm to 15 mm thick tube sections. The influence of process parameters such as the laser ramp time, the change in magnification scale and the defocusing of the laser beam on the solidifi-cation conditions at the end of the circumferential weld was investigated to find an optimum strategy for ramping out the process energy. Within the framework of the experimental studies, it was demonstrated that defocusing the laser beam in the range between 60 mm and 100 mm over a short run-out area of the weld of approximately 15 mm led to a significantly better weld formation in the overlap area. A favourable cup-shaped weld shape could be achieved without a tendency to crack. The laser optics with a motor-driven lens system made it possible to increase the laser beam diameter without changing the position of the GMAW arc relative to the component surface. KW - Weld defects KW - Hybrid welding KW - Laser beam welding KW - Pipe manufacturing KW - Gas shielded arc welding PY - 2021 VL - 20 IS - 4 SP - 334 EP - 339 PB - DVS Media AN - OPUS4-54665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -