Yogesh Kumar Singla

This review focuses on the materials development utilized for enhancing long-term efficiency of hydropower plants and its sustainability. It begins by contextualizing the global transition toward renewable energy, distinguishing between renewable and non-renewable energy sources, and underscoring the strategic importance of hydropower in meeting growing ecological and energy demands. The study delves into the technological evolution of hydroelectric systems, with a focused analysis on the engineering design and materials employed in the underwater parts of hydro turbines susceptible to mechanical degradation. A comprehensive evaluation of materials is presented ranging from traditional options like wood and cast iron to modern solutions such as stainless steels, advanced steel alloys, polymer matrix composites, and nano-engineered materials, with a focus on their mechanical properties and resistance to cavitation, erosion, corrosion, and fatigue. The review also highlights surface modification and various processing such as heat treatment and thermomechanical processing techniques aimed at enhancing material performance under aggressive hydro-operating conditions. Finally, the paper identifies the key challenges in material selection and development for hydropower applications and outlines future directions needed to ensure improved durability, reduced maintenance, and overall enhancements in the efficiency of hydro turbine and sustainability of hydropower plants.

This research investigates the impact of shielded metal arc welding (SMAW) electrode coating flux on microhardness, microstructure, and element transfer. A mixture design approach was employed to formulate the flux compositions, and multi-pass bead-on-plate experiments were conducted. Regression analysis was used to evaluate the relationship between microhardness and weld bead chemistry. The results indicated that the presence of CaO, Al ₂ O ₃ , and SiO ₂ positively influences the transfer of nickel from the electrode to the weld pool. Increased levels of Na ₃ AlF ₆ , SiO ₂ , and CaO positively affected chromium transfer, while Al ₂ O ₃ led to a decrease in chromium transfer. Manganese transfer was enhanced by CaO and Na ₃ AlF ₆ , but reduced with higher concentrations of Al ₂ O ₃ and SiO ₂ . Furthermore, an increase in SiO ₂ raised the oxygen potential, contributing to a loss of manganese in the Weld. The results indicate that increasing Al ₂ O ₃ positively affects iron transfer, while higher concentrations of Na ₃ AlF ₆ , SiO ₂ , Al ₂ O ₃ , and CaO improve niobium transfer. Microhardness increases with higher levels of CaO, Na ₃ AlF ₆ , and SiO ₂ , although Al ₂ O ₃ has a reducing effect. The welds were further analyzed through microstructural analysis. In addition, artificial neural network (ANN) models were developed, demonstrating improved prediction accuracy compared to traditional approaches.