The influence of high and low temperature environment on hydraulic oil

Hydraulic oil plays a role in energy transfer, anti-wear, system lubrication, corrosion prevention, rust prevention, cooling, and other functions in hydraulic systems. For hydraulic oil, the first requirement is to meet the viscosity requirements of the hydraulic device at both operating and starting temperatures. Each type of hydraulic oil has a certain range of applicability, and temperatures that are too high or too low can have adverse effects on hydraulic oil. So, what are the effects of high and low temperature environments on hydraulic oil?

The influence of low temperature on hydraulic oil

1. Low temperature increases the viscosity of hydraulic oil. If the viscosity is too high, the self-priming ability of the oil pump will decrease, the pressure loss of the hydraulic system will increase, and the power loss will increase. It is generally believed that when the viscosity is greater than or equal to 1000mm2/s, the hydraulic system cannot work properly, and when the viscosity is greater than or equal to 2000mm2/s, the hydraulic system cannot start normally.

2. Low temperature causes water in hydraulic oil to solidify, and the solidified water adheres to the surfaces of hydraulic valve parts, oil filters, etc., which may cause the hydraulic valve to get stuck, the oil filter to become clogged, and the hydraulic system to malfunction.

3. Low temperature causes shrinkage and hardening of rubber sealing materials in hydraulic systems, reducing sealing performance and even leading to sealing failure.

4. Low temperature causes hydraulic oil to contract, especially in enclosed chambers, resulting in a decrease in pressure or even negative pressure.

The Effect of High Temperature on Hydraulic Oil

1. When the temperature is high, the viscosity of hydraulic oil decreases. If the viscosity is too low, the leakage of the hydraulic system increases, the efficiency decreases, and even the hydraulic system cannot work normally.

2. High temperature intensifies the oxidation of hydraulic oil, gradually generating some ketones, acids, colloids, and asphaltene substances in the hydraulic oil, polluting the hydraulic oil and shortening its service life. When the hydraulic oil oxidizes to a certain degree, the hydraulic oil becomes ineffective and cannot be used.

3. The high temperature causes the oil film formed on the metal surface of the friction part to undergo chemical decomposition, and the lubricating film is damaged.

4. High temperatures often exacerbate the corrosion of steel and other metals in hydraulic oil. Causing surface damage to the parts and generating corrosive substances.

5. High temperatures are more likely to generate bubbles, which can damage the lubricating oil film, cause sintering or increase wear on the friction surface, and accelerate the oxidation and deterioration of hydraulic oil, affecting the accuracy and sensitivity of hydraulic components. In severe cases, it cannot meet the requirements of hydraulic system use.

6. High temperature deteriorates the performance of rubber seals in hydraulic systems, causing rubber to swell, soften, accelerate rubber aging, and even seal failure.

7. High temperature causes the volume of hydraulic oil to expand, leading to an increase in pressure within the enclosed chamber and posing a danger.