This research investigates the influence of cryogenic treatment duration on the mechanical and microstructural properties of manganese steel and cast steel, materials commonly employed in impact-intensive and structural applications. Cryogenic treatment was conducted at –80°C for 12 and 24 hours to determine its impact on material performance enhancement, particularly focusing on hardness, tensile behavior, and microstructure refinement. Mechanical characterization included Vickers hardness testing and tensile testing, while microstructural observations were carried out using Scanning Electron Microscopy (SEM). For manganese steel, cryogenic treatment led to a substantial improvement in hardness, with a 7% increase observed after 24 hours. Yield strength and stiffness also showed modest improvements, attributed to austenite-to-martensite transformation and carbide precipitation. However, overexposure beyond 12 hours slightly compromised ductility, indicating an optimal balance is necessary between strength and formability. Cast steel, with lower alloying content, showed more modest gains in hardness (~2%) and stiffness, with tensile strength peaking at 12 hours before declining after 24 hours, likely due to microstructural embrittlement. SEM analysis confirmed that cryogenic treatment improved grain refinement and reduced internal defects in both steels, although more prominently in manganese steel. The study concludes that cryogenic soaking for 12 hours provides an optimal treatment window, improving mechanical properties with minimal trade-offs in ductility. The findings support the use of cryogenic treatment as a cost-effective and practical enhancement method for structural steels in demanding applications, with optimal results depending on alloy composition and soaking time.