Laserstrahlschweißen von Titanwerkstoffen unter Berücksichtigung des Einflusses des Sauerstoffes

Abstract

Ferner konnte nachgewiesen werden, dass die Qualitätsmerk-male der derzeitigen Regelwerke für das WIG-Schweißen für die Luft-und Raumfahrttechnik auf das Verfahren Laserstrahlschweißen mit Nd:YAG-Quellen übertragen werden können.Schlüsselworte: Titan, Laserstrahlschweißen, Anlauffarben, Ermüdung In the present work, a new tool concept for laser welding of titanium in high volume production has been presented and evaluated. Through the innovative application of a six-layer metal web it is possible to calm the argon gas flow and avoid pernicious turbulences during welding. The integration of the mentioned metal web at the base of an open welding chamber allows the automated welding of highly reactive materials, such as titanium, under atmospheric pressure and inert shielding conditions. The higher density of argon relative to air offers the unique possibility to leave the chamber open on the top, so that a higher degree of flexibility than gas shielding devices for TIG welding, especially for industrial robots, is attained and can be successfully used for industrial mass production. Furthermore this device is important for welding threedimensional contours or to shield the regions of overlap (in overlapped joints) where shielding gas trailers are unsuccessful. By means of the presented gas shielding procedure and a modern laser welding process such as Nd:YAG laser welding, systematic investigations on the effect of oxygen on the microstructure as well as on the mechanical properties of reference bead-on-plate weldments could be performed for the first time. As a result of these welding trials it can be concluded that in order to avoid discolorations and hardness increase, lower restrictions to the purity of the shielding gas, in comparison to TIG welding condition, can be allowed. The maximum tolerable value of oxygen in the welding atmosphere was found to be approximately 1000 ppm for laser welding. On the contrary the maximum value for TIG welding is about 30 ppm.Further investigations on the microstructural and mechanical properties of the joints confirm that the optical quality assurance criteria for TIG welding due to the standards of aircraft construction transferable to Nd:YAG welding are.

Wire based additive layer manufacturing: Comparison of microstructure and mechanical properties of Ti–6Al–4V components fabricated by laser-beam deposition and shaped metal deposition

“…In order to prevent oxidation during deposition the ALM was performed in an open box, which is permanently flooded by argon (99.9996% purity) from its base (design of the box based on (Bergmann, 2004)). The setup was developed at EADS Innovation Works in Ottobrunn/Munich (Germany) (Brandl et al, 2008(Brandl et al, , 2009a.…”

Investigation of Generatively Manufactured Components in a Sealed Welding Chamber Using the Tungsten Inert Gas Hot Wire Process

“…Another aspect concerns the handling of fluids and sensors in the running process. The important fluids and sensors are fed through the rotating unit and the oxygen sensor, respectively, which measures a residual oxygen content of 30-50 ppm when using the alloy Ti6Al4V, through the upper end of the chamber [19]. This should ensure that no negative influence on the corresponding components can occur due to direct contact with the weld metal.…”