Computational Modeling:A Path to Expand the Knowledge Base in Fusion Welding

Welded joints contain spatial variations of composition, structure and properties that are affected by heat transfer, flow of molten metal in the weld pool and solid state transformations during welding. The main challenge in the control of weld properties originates from the complexity of both the fusion welding processes as well as the welded materials. Solutions of complex welding problems based on scientific principles under the framework of computational modeling are already providing solutions for a variety of problems. Computer models of heat transfer, fluid flow and thermal cycles can now be relied upon to provide fusion zone geometry, temperature fields and thermal cycles with a fair degree of confidence. Significant progress has also been made in building a quantitative understanding of various structural features such as phase composition, grain structure and inclusion structure, mostly for several relatively simple alloys. In order to understand and eventually control welding processes and welded materials, significant expansion of our current quantitative understanding of various aspects of welding is necessary. The expanded knowledge base can serve as a basis for the control of welding processes, greatly enhance the quality, reliability and serviceability of welded structures and transform welding to a mainstream engineering branch. Achievement of this challenging but realistic goal, an important milestone in the advancement of welding technology, is well within the reach of the welding community.