Mixing 46# And 68# Hydraulic Oils: Benefits, Risks, And Best Practices

The selection of hydraulic oil in hydraulic equipment is crucial. Various hydraulic oils have different viscosities and properties. Common hydraulic oils include 46 hydraulic oil and 68 hydraulic oil. Some people may think that since they are both hydraulic oils, using them together should be fine. If you have this idea, please stop your bold idea. They should not be mixed together.

1. The Meaning of Hydraulic Oil Numbers

The number before the hydraulic oil refers to its viscosity, which is the oil's fluidity. The higher the viscosity, the poorer the oil's fluidity at high temperatures, making it suitable for high-load, low-speed working environments. On the other hand, lower viscosity hydraulic oil is suitable for low-temperature, high-speed applications.

46# Hydraulic Oil: Its viscosity is approximately 46 mm²/s at 40°C, and is usually used in medium-load and working temperature conditions that are higher.
68# Hydraulic Oil: Its viscosity is approximately 68 mm²/s at 40°C, and is suitable for high-load or high-temperature environments.

2. Why is it not recommended to mix hydraulic oil No. 46 with hydraulic oil No. 68?

Viscosity difference: The viscosity difference between hydraulic oil No. 46 and No. 68 is quite large, and mixing them will change the overall viscosity of the oil, resulting in unstable fluidity of the hydraulic system and affecting the performance of the equipment.

Performance differences: Different hydraulic oils may contain different additives, and when mixed, they may undergo chemical reactions, causing a decrease in the oil's oxidation resistance, wear resistance, and corrosion resistance, reducing the lifespan and efficiency of hydraulic equipment.

Fluctuations in system pressure: The hydraulic system has strict requirements for the viscosity of the oil. If the viscosity is too low or too high, it will cause instability in system pressure, and even equipment failure.

3. What if mixing is necessary?
While mixing different viscosity grades of hydraulic oil is not recommended, if it is necessary due to special circumstances, the following points should be noted:

Same brand and type of oil: Try to mix the same brand and type of hydraulic oil as much as possible, which can reduce the problems caused by differences in oil performance.
Check compatibility: Before mixing, it is best to consult with the oil supplier to ensure that the components and additives of the two oils will not react negatively.

Mix Ratio Control: Try to keep the mixture ratio of 46-number oil and 68-number oil within a reasonable range, avoiding excessive dilution or concentration.

Monitor the operation of the hydraulic system: Mix the solution and regularly check the operation of the hydraulic system, observing for any unusual phenomena such as overheating, leaking oil, or pressure fluctuations.

To ensure the stability of the hydraulic system and the long-term reliable operation of the equipment, it is recommended to select the appropriate viscosity hydraulic oil according to the specific working environment and requirements, and strictly follow the usage specifications of the oil.