Numerical Simulations and Experimental Validation on LBW Bead Profiles of Ti-6Al-4V Alloy

Abstract

The lightweight titanium alloys possess good resistance to corrosion and temperature. They are used in turbine engines and aircraft structures. The strength of weld joint is dependent on thermal history in the weld zone and the weld bead geometry. The quality of weld can be improved by specifying the optimal welding parameters. Trial-and-error experimental methods are time-consuming and expensive. This paper deals with Computational Fluid Dynamics (CFD) models to carry out three-dimensional thermo-fluid analysis. Buoyancy and Marnangoni stress are incorporated. Temperature dependent properties of Ti-6Al-4V alloy and the process conditions are specified for generating the weld bead profile. The CFD model is validated initially through comparison of existing test data. Further studies are made by conducting tests on the pulsating laser welding of Ti-6Al-4V alloy. The effects of welding speed, pulse width and pulse frequency on the weld bead geometry are examined. This study confirms the adequacy of modeling and simulations of weld bead geometry with test results.