Authors Ayuba Elkanah JatauDepartment of Mechanical Engineering, School of Infrastructure, Process Engineering and Technology, Federal University of Technology Minna, Niger State, Nigeria & Department of Mechanical Engineering, Niger State Polytechnic Zungeru, Niger State, NigeriaIsah MuhammadDepartment of Mechanical Engineering, School of Infrastructure, Process Engineering and Technology, Federal University of Technology Minna, Niger State, NigeriaElkanah Bagudu SamuelDepartment of Welding Engineering and Offshore Technology, Petroleum Training Institute, Effurun, Delta State, Nigeria Abstract Underwater welding is essential for marine infrastructure maintenance, but wet‐arc processes suffer severe weld defects due to water vapor dissociation and high hydrogen levels in the weld pool. Conventional electrodes (rutiles, basic fluxes) still generate high diffusible hydrogen and hard HAZs, limiting weld quality. As a sustainable alternative, this review examines agrowaste‐derived biomaterials (rice husk, bagasse, coconut shell, corn stover, banana peel, etc.) as flux and coating components for underwater welding electrodes. We compare the feedstock chemistry (lignocellulose, ash/minerals) of each biomass, the conversion processes (pyrolysis, activation, pelletizing, sintering, binder selection), and electrode formulations proposed in recent studies. The review summarizes welding performance data (mechanical strength, hardness, H₂ content, porosity) for bio‐flux electrodes versus conventional fluxes. It also analyzes arc stability and metallurgical effects: how carbonaceous slag and K/Ca silicates from biomass influence the arc and mitigate hydrogen ingress. Environmental and economic impacts are assessed through preliminary life‐cycle analysis, highlighting carbon footprint reductions and cost savings from using waste biomass. Finally, we identify critical research gaps in welding metallurgy such as hydrogen entrapment, slag-metal reactions, material processing (scale‐up of biochar electrodes), and regulatory issues. This review provides a comprehensive roadmap for developing sustainable underwater welding electrodes from agrowaste, to maintain weld quality while reducing environmental impact. Keywords Underwater welding; welding electrodes; biomass flux; agrowaste; biochar; hydrogen embrittlement; arc stability; life-cycle assessment; sustainable materials. Citation of this Article Ayuba Elkanah Jatau, Isah Muhammad, & Elkanah Bagudu Samuel. (2026). Agrowaste‐Derived Biomaterials for Sustainable Underwater Welding Electrodes: A Review. Current Journal of Engineering and Science Research. 3(7), 1-14. Article DOI: https://doi.org/10.47001/CJESR/2026.307001 Licence Copyright (c) 2026 Current Journal of Engineering and Science Research. 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