What does ISO 46 mean on Hydraulic oil?

ISO 46 refers to the viscosity grade of hydraulic oil as defined by the International Organization for Standardization (ISO). The number 46 indicates the oil's kinematic viscosity at 40°C, which is approximately 46 centistokes (cSt). This viscosity level is suitable for various hydraulic systems, providing adequate lubrication and performance under moderate temperatures and pressures. ISO viscosity grades help ensure compatibility and effective operation in hydraulic machinery.