When purchasing high carbon steel (typically containing 0.60% to 1.00% carbon), you must prioritize the chemical composition balance. Ensure the Carbon (C) content aligns with your specific hardness requirements, and check the levels of Manganese (Mn), which affects hardenability. For industrial applications, verify the tensile strength and yield strength through mill test reports. Additionally, specify the surface finish (e.g., cold-rolled, hot-rolled, or polished) and dimensional tolerances (thickness and width) to ensure compatibility with your manufacturing machinery.