Surface roughness plays a critical role in determining friction factors in circular tubes, significantly influencing the efficiency and performance of fluid transport systems. This paper focuses on the impact of surface roughness on friction factors in galvanized steel (GS) and stainless steel (SS) circular tubes, highlighting the differences and implications for practical engineering use. By analysing these effects, the research aims to provide valuable insights for optimizing of material selection and design in fluid flow applications. The study simulates turbulent flow conditions within pipes of changing surface roughness, perfectly creating real-world situations by determining precise parameters for pipe geometry, fluid characteristics, and boundary conditions. The research involves constructing a complete 3D geometry of the tubes in ANSYS Workbench. Turbulence models and mesh refinement techniques provide precise visualizations of flow events and boundary layer effects. Results demonstrate a significant correlation between increased surface roughness and higher friction factors, with friction factors decreasing as the Reynolds number increases. Specifically, galvanized steel exhibits an 8% higher friction factor than stainless steel due to its greater absolute roughness of 0.15 mm. The results show that smoother SS tubes reduce flow resistance and improve efficiency. Validation against experimental data and proven correlations confirms the durability and reliability of the simulation models. The study emphasizes the significance of solving surface roughness in the design and optimization of pipe systems to improve energy efficiency and minimize pressure drops. These findings are crucial for enhancing fluid transport systems across wide-ranging industrial applications, providing an environment for further research on the impacts of surface roughness on different materials and flow conditions.