Analysis of macrosegregation near fusion boundary in fusion welding

AbstractA model is presented for the prediction of the post-solidification solute distribution of a single phase alloy in a fusion weld. It takes into account the shape and size of the weld pool, the acceleration of growth rate as a solidifying crystal curves from the fusion boundary towards the weld centreline in an oval weld pool, the melting stage prior to the solidification and the diffusion in solid. Temperature dependencies of diffusion coefficients are included. The proposed model and analogous solidification models are categorised with a system consisting of Cases and Sub-Cases. The thermodiffusional problem is solved numerically. It is shown that the solid diffusion during the melting stage may essentially affect the post-solidification solute distribution near the fusion boundary. Radiographical experiments on sulphur support the calculations. The model is restricted to planar growth, until microsegregation is included.