MODELLING OF WELDING PARAMETERS ON BEAD GEOMETRY IN ND: YAG LASER WELDING OF TITANIUM WITH TI-6AL-7NB USING RESPONSE SURFACE (RSM)

Abstract

Pulsed laser welding is a powerful technique especially suitable for joining thin sheet metals. In this study, based on experimental data, pulsed laser welding of thin Cp- Ti and Ti-6Al-7Nb sheets has been optimized. The experimental data required for modeling are gathered as per Central Composite Design matrix in Response Surface Methodology (RSM) with full replication of 30 runs. Response Surface Methodology is used to investigate the effect of four input variables, namely: type of workpiece (WP), pulse energy (PE), pulse duration (Ton), welding speed (WS) and on the depth of penetration and bead width in YAG laser welding process. To study the proposed second-order polynomial model for DOP and BW, a Central Composite Design is used for estimating the model coefficients of the four input factors on DOP and BW. Experiments were conducted on Cp- Ti alloy with Ti-6Al-7Nb alloy. The significant coefficients are obtained by performing an Analysis of Variance at the 5 % level of significance. The results revealed that DOP and BW are more influenced by type of workpiece, pulse energy, pulse duration, welding speed and few of their interactions. A mathematical regression model was developed to predict both of DOP and BW in YAG laser welding. Also, the developed model could be used for the selection of the levels in this process for saving in welding time.