Mathematical Modelling of Fluid Flow and Heat Transfer in Fusion Welding

Recent computer modelling of weldment geometry, chemical composition, and structure has provided unmatched quantitative insight into fusion welding processes and weldment properties not attainable by experiments alone. Several case studies are presented to demonstrate the importance of numerical modelling in advancing the science of fusion welding. For example, numerical modelling has recently revealed why the presence of surface active elements in the weld metal does not always produce the expected enhancements in the depth of penetration. Similarly, the peculiar shapes of gas metal arc welds have been predicted a priori from computer modelling. Compositional changes resulting from alloying element vaporisation and gas dissolu­tion have also been predicted. Computer modelling of phase compositions, grain structure, and inclusion characteristics based on transport phenomena and phase transformation theory has provided mechanistic and other insights not attainable solely through even the most ambitious experiments.