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7165 |
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Tuesday, June 21, 2022, Saal Brüssel 11:00 AM Furnace brazing |
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Effects and developments of pressure aided brazing on large scale, planar joints |
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Felix Gemse* / Günter-Köhler-Institut für Fügetechnik und Werkstoffprüfung GmbH (ifw Jena), Germany Jan Pfeiffer / PVA Löt- und Werkstofftechnik GmbH, Germany Patrick Müller/ PVA Löt- und Werkstofftechnik GmbH, Germany Martin Salge/ Günter-Köhler-Institut für Fügetechnik und Werkstoffprüfung GmbH, Germany |
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Vacuum brazing as a joining technology is an established standard process for a wide range of applications and industries. Which is also reflected in the extensive standardization. In the recent years, an increasing growth of the component size and planar brazing area inside the components can be observed. In particular, the mould and tooling industry, the petrochemical industry and thermal management are raising the demand for large-scale components with more than 500 mm edge length. A major challenge in brazing large-format components is the component distortion that occurs during the brazing process, due to release of residual stresses, thermal gradients or phase transformations. This leads to the formation of larger gaps between the parts to be joined, which ether alter the mechanical stability of the joint or, in the worst case cannot be bridged by the filler material. Accordingly, brittle phases, bonding defects and leakages frequently occur in such assemblies. Up to now, this problem has been countered by the use of toolings or brazing jigs for fixing and clamping the parts. Accompanied with obvious disadvantages like the additional mass that these devices bring into the process, which must be heated and cooled, is the reduction of furnace space which is consumed by the additional devices. An approach to overcome the mentioned disadvantages and to establish a more reliable vacuum brazing procedure, is the utilization of a controlled external force application. Which allows a defined load application at any time of the brazing process without the drawbacks of jigs. In the presented work actual developments and technical solutions for load application will be shown. Further the impact on the joint formation in microscopic scale as well as the mechanical properties will be presented. Furthermore, the achievable component performance will be shown on successfully realized applications. |