Heat Transfer in a Stud-to-Plate Laser Braze Considering Filler Metal Movement

摘要

A finite element model has been developed for the thermal analysis of a miniature stud-to-plate laser brazing process, and the transient temperature fields in the braze joint were analyzed by using an axisymmetric model. The finite element program ABAQUS, together with a few user subroutines, were employed to perform the numerical approximation. The joining materials used were AISI 304 stainless steel and Al 5052 aluminum, and the alloy 88Al-12Si for the braze filler metal. Nonlinear effect of temperature dependent thermal properties, latent heat and the convection and radiative heat losses were considered. The FE modeling was implemented with a non-coupled treatment of heat conduction and filler metal flow, while the model was based upon the real-time motion analysis of the brazing process. Definition of the FE solution domain and boundary conditions were crucial to achieve accuracy in predicting the transient thermal behavior, possible only with the aid of a high-speed camera. Numerical results of the temperature fields in the braze joint were obtained for typical process parameters. The predicted thermal histories show a fairly good agreement with the experimental ones that were determined by using the thermocouple and infrared temperature measurements.