The influence of high and low temperature environment on hydraulic oil
August 31, 2021
Hydraulic oil plays the role of energy transfer, anti-wear, system lubrication, anti-corrosion, anti-rust, and cooling in the hydraulic system. For hydraulic oil, first of all, it should meet the requirements of hydraulic device for liquid viscosity at working temperature and starting temperature. Each hydraulic oil has a certain range of use. Too high or too low temperature is unfavorable to hydraulic oil. So what are the effects of high and low temperature environment on hydraulic oil?
The effect 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 normally, and when the viscosity is greater than or equal to 2000mm2/s, the hydraulic system cannot be started normally. (2) The low temperature causes the water in the hydraulic oil to solidify, and the solidified water adheres to the surface of the hydraulic valve parts, oil filter, etc., which may cause the hydraulic valve to jam, the oil filter to block, and the hydraulic system cannot work normally. (3) The low temperature causes the rubber sealing material in the hydraulic system to shrink, harden, etc., reducing the sealing performance and even causing the seal to fail. (4) The low temperature causes the hydraulic oil to shrink, especially the hydraulic oil in the closed cavity, which causes the pressure to drop and even produces negative pressure.
The effect of high temperature on hydraulic oil (1) High temperature causes the viscosity of hydraulic oil to decrease and the viscosity is too low, the leakage of the hydraulic system increases, the efficiency decreases, and the hydraulic system even fails to work normally. (2) High temperature intensifies the oxidation of hydraulic oil. Some ketones, acids, gums, asphaltenes and other substances are gradually generated in the hydraulic oil, which contaminates the hydraulic oil and shortens the service life of the hydraulic oil. When the hydraulic oil is oxidized to a certain degree, the hydraulic oil fails and cannot be used. (3) The high temperature causes the chemical decomposition of the lubricating film formed on the metal surface of the friction part, and the lubricating film is destroyed. (4) High temperature often causes the corrosion of steel and other non-ferrous metals in hydraulic oil to intensify, resulting in damage to the surface of parts and corrosives. (5) High temperature is more likely to produce 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, which affects the accuracy and sensitivity of hydraulic components, and cannot meet the requirements of hydraulic systems in severe cases. . (6) High temperature deteriorates the performance of rubber seals in hydraulic systems, which can swell and soften rubber, accelerate rubber aging, and even seal failure. (7) High temperature expands the volume of hydraulic oil, which increases the pressure of the hydraulic oil enclosed in the cavity, causing danger.
