This review critically considers recent advances in flux composition for flux-assisted tungsten inert gas welding methods viz. activated tungsten inert gas and flux-bounded tungsten inert gas. This manuscript, looking beyond the penetration-focused discussions, integrates new flux design approaches such as nanoparticle-enhanced, multicomponent, and sustainability-based flux systems that assess their mechanistic roles in arc constriction, reversal of Marangoni convection, and arc-pool interactions. Among the novelties here is a holistic analysis of flux chemistry-process-property relationships across a wide range of alloy systems, with particular emphasis on material-specific responses and inevitable trade-offs between penetration enhancement, microstructural stability, and mechanical integrity. Contradictions and divergences in reported results are deeply analyzed. Laboratory-scale observations are also placed in the context of recorded industrial applications, documenting reasons for poor large-scale adoption: flux sensitivity, lack of standardization, and environmental concerns. Through bringing together the fundamental mechanisms, engineering implications, and future research priorities, this work will provide a process-engineering-based framework to take flux-assisted tungsten inert gas welding forward toward robust and industrially deployable solutions.
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