Modeling Continuous-Wave Laser Beam Welding of Titanium Alloy: A Computational Approach
Author : Jessy
Publisher :
Page : 0 pages
File Size : 14,27 MB
Release : 2024-06-08
Category :
ISBN : 9783384254566
Author : Jessy
Publisher :
Page : 0 pages
File Size : 14,27 MB
Release : 2024-06-08
Category :
ISBN : 9783384254566
Author : Molina
Publisher :
Page : 0 pages
File Size : 15,83 MB
Release : 2024-06-10
Category :
ISBN : 9783384256553
Author : Jonathan Edward Blackburn
Publisher :
Page : pages
File Size : 33,47 MB
Release : 2011
Category :
ISBN :
Keyhole laser welding is a joining technology characterised by the high focussed power density applied to the workpiece, facilitating deep penetration at high processing speeds. High aspect-ratio welds produced using this process invariably have narrow heat-affected-zones and minimal thermal distortion compared with traditional arc welding processes. Furthermore, the ability to process out of vacuum and the easy robotic manipulation of fibre optically delivered 1[mu]m wavelength laser beams, allow keyhole laser welding to process geometrically complex components. The widespread uptake of keyhole laser welding for the production of titanium alloy components in the aerospace industry has been limited by the stringent weld quality requirements. Producing welds with levels of subsurface weld metal porosity content meeting the required weld quality criteria has been the primary obstacle. Here, three techniques for controlling the levels of weld metal porosity when welding titanium alloys with Nd:YAG rod lasers have been developed. Characterisation of the welding processes using high speed photography and optical spectroscopy, have allowed an original scientific understanding of the effects these methods have on the keyhole, melt pool and vapour plume behaviour. Combining this with a thorough assessment of the weld qualities produced, has enabled the effects of these process behaviours on the formation of weld metal porosity to be determined. It was found that with the correct process parameters a directed gas jet and a dual focus laser welding condition can both be used to reduce the occurrence of keyhole collapse during Nd:YAG laser welding. The directed gas jet prevents the formation of a beam attenuating vapour plume and interacts with the molten metal to produce a stable welding condition, whereas the dual focus laser welding condition reduces fluctuations in the process due to an enlarged keyhole. When applied, both techniques reduced the occurrence of porosity in the weld metal of full penetration butt welds produced in titanium alloys. A modulated Nd:YAG laser output, with the correct waveform and modulation frequency, also reduced the occurrence of porosity in the weld metal compared with welds produced with a continuous-wave output. This was a result of an oscillating wave being set-up in the melt pool which manipulated the keyhole geometry and prevented instabilities in the process being established. In addition, the potential for welding titanium alloys to the required weld quality criteria with state-of-the-art Yb-fibre lasers has been assessed. It was found that the high power densities of suitably focussed laser beams with excellent beam quality, were capable of producing low-porosity full penetration butt welds in titanium alloys without the techniques required for laser beams with a lower beam quality. These new techniques for keyhole laser welding of titanium alloys will encourage the uptake of keyhole laser welding for producing near-net-shape high-performance aerospace components. The advantages offered by this joining technology include high productivity, low heat input and easy robotic automation.
Author : Jonathan Montalvo-Urquizo
Publisher :
Page : 162 pages
File Size : 38,3 MB
Release : 2008
Category : Laserschweißen - Aluminiumlegierung - Simulation - Numerisches Verfahren
ISBN : 9783899638318
Author : Tobias Buccho
Publisher :
Page : pages
File Size : 21,15 MB
Release : 2019-02-15
Category :
ISBN : 9781956256048
This book deals with pulsed mode laser beam welding (LBW) on 2 mm thick Ti-6Al-4V alloy sheets. ANSYS Fluent 16.0 version is utilized to develop a generic model with Vc++ code. The model is validated with test results. The optimal LBW parameters are obtained bymaximizing the depth of penetration (DP) and minimizing the weld bead width (BW). To minimise the number of numerical simulations, Taguchi approach is adopted.The LBW parameters considered are pulse frequency, pulse width and welding speed,theabsorbed power is kept as constant.The performance indicators are width of fusion zone, depth of penetration, heat affected zone and maximum temperature. The optimal LBW parameters are found to be dependent onthe process indicators. A simple reliable modified Taguchi approach is followed to get a set of optimal LBW parameters for maximum DP and minimum BW.
Author :
Publisher :
Page : 1042 pages
File Size : 47,72 MB
Release : 1999
Category : Aeronautics
ISBN :
Author :
Publisher :
Page : 704 pages
File Size : 10,28 MB
Release : 1995
Category : Aeronautics
ISBN :
Author : K. C. Mills
Publisher : Woodhead Publishing
Page : 288 pages
File Size : 26,76 MB
Release : 2002
Category : Alloys
ISBN : 9780871707536
Author :
Publisher :
Page : 1076 pages
File Size : 12,92 MB
Release : 1998
Category : Metallurgy
ISBN :
Author :
Publisher :
Page : 348 pages
File Size : 11,17 MB
Release : 1992
Category : Mechanics, Applied
ISBN :