What effects does high temperature have on hydraulic oil?

Hydraulic systems also convert energy into heat during operation, and inefficiencies can increase heating of the hydraulic fluid. Efficiency can be reduced when the cylinder is not suitable for the application (for example, a slow-speed jacking cylinder used in a high-repetition, high-duty-cycle application). Normal wear can also lead to increased friction and poor operation, which reduces efficiency. This is why a well-designed and well-maintained hydraulic system will not usually overheat. But the lower the efficiency and the worse the conditions, the more heat will be generated.

High temperatures can have an adverse effect on hydraulic systems, which are not designed to handle this. This article introduces the effects of high temperatures on hydraulic oil. .

1) Higher heat equals lower oil viscosity.

You might think that hydraulic oil is oil and can withstand extreme temperatures. After all, motor oil is found in internal combustion engines and can survive thousands of hours at high temperatures. However, this is not always the case, and the reason is simple. Motor oil viscosity changes with temperature. At high temperatures, the oil becomes thinner. This is important because hydraulic oil is also responsible for lubrication within the hydraulic system. Oil with lower viscosity has poorer lubrication properties and can no longer protect reciprocating parts to a certain extent. So, the higher the oil temperature, the greater your chances of experiencing accelerated mechanical wear. This means you will be replacing pumps and cylinders more often.

2) Increased heat leads to increased oxidation.

Oxidation is a chemical reaction that occurs when air is present in a hydraulic system. Oxidation is one of the main reasons for reduced stability of hydraulic oil and causes the oil to turn black and become contaminated. The chemical reaction leads to the formation of acids, which increase fluid viscosity and cause corrosion, gumming, varnishing, and slow operation. The worst part is that the rate of this chemical reaction doubles for every 10 degrees increase in temperature. So, the hotter the oil, the faster it oxidizes.

3) Heat affects the life of the hydraulic oil.

The bottom line is that too much heat can have a significant impact on the life of the hydraulic oil, and poor maintenance can lead to inefficiencies and heat. This has a cascading effect on the entire system. In other words, if you can't repair a component when it starts to get abnormally hot, you may increase wear on other parts of the hydraulic system and you will be replacing more components in a short period of time.