China lubricating oil network oil testing department, specializing in hydraulic oil testing, has certain technical experience in hydraulic oil testing. Hydraulic oil is the hydraulic medium used in the hydraulic system which uses the liquid pressure energy. It plays the role of energy transmission, system lubrication, anti-corrosion, anti rust, cooling and so on. For hydraulic oil, the requirements for liquid viscosity of hydraulic device at working temperature and starting temperature should be met first. Since the viscosity change of oil is directly related to hydraulic action, transmission efficiency and transmission accuracy, the viscosity temperature performance and shear stability of oil should meet various requirements for different purposes.

The hydraulic system of automobile and construction machinery uses hydraulic oil as working medium. In this kind of hydraulic system, the flow rate of oil is small and the pressure is high, so it is called hydrostatic transmission. The quality of hydraulic oil will affect the working reliability and service life of hydraulic system to a great extent.

Generally, the quality requirements of hydraulic oil are as follows:

1. Suitable viscosity and good viscosity temperature performance can ensure accurate and sensitive transmission of power and normal lubrication of hydraulic components when the working temperature changes.

2. It has good rust resistance and anti-oxidation stability, and is not easy to be oxidized and deteriorated under high temperature and high pressure, and has a long service life.

3, good foam resistance, so that the oil generated under the continuous stirring of machinery, the foam is easy to disappear, eight so that the power transmission is stable, to avoid accelerated oxidation of hydraulic oil.

4. Good demulsibility, can be quickly separated from the water mixed with oil, forming emulsion in rabbits, resulting in corrosion of metal materials in hydraulic system and reducing the use effect.

5. Good extreme pressure and wear resistance, to ensure that the friction pairs in hydraulic oil pump, hydraulic motor, control valve and oil cylinder get normal lubrication under high pressure, high speed and harsh conditions, and reduce wear.

In addition to the above basic quality requirements, there are special requirements for some special performance requirements of hydraulic oil. For example, low-temperature hydraulic oil requires good low-temperature performance; fire-resistant hydraulic oil requires good fire-resistant performance; silver resistant hydraulic oil can be used in hydraulic systems with silver components.

Generally, the quality inspection of hydraulic oil mainly includes the following items:

(1) The viscosity should be strictly tested. If the viscosity is too high, the power loss will be increased; if the viscosity is too small, the wear will be affected and the internal leakage of the pump will be increased, and the system pressure will be decreased.

(2) The viscosity index of oil for indoor fixed hydraulic system is more than 90, while that for mobile equipment in cold area is greater than 130

(3) Water content and moisture damage the oil film, reduce the lubricity, aggravate the wear of friction parts, react with the oil, form acid, gum and oil slurry, and precipitate the additives in the oil, reduce the service performance of the oil, and make the fluidity of the oil worse at low temperature, corrode and rust the metal materials of the equipment

(4) anti foaming hydraulic oil will be mixed into the air during operation, resulting in the decline of the efficiency of the system and even the damage to the equipment. Therefore, the hydraulic oil is required to have good anti foam performance.

(5) Pour point for the use of hydraulic oil in cold areas, to have a good low temperature performance. Pour point is the main measure. When selecting lubricating oil, the lubricating oil with pour point 10-20 ° C lower than the ambient temperature is generally selected.

(6) Corrosion resistant hydraulic oil is more polluted by the outside world, and some hydraulic control components are also very precise. Corrosion is very harmful to it

(7) Pollution degree analysis pollution degree analysis can quantitatively detect the quantity and level of pollution particles in lubricating oil; for precision hydraulic system, solid particle pollution will aggravate the wear of control components; for turbine system, solid particle pollution will aggravate the wear of components such as bearings

(8) The anti-wear performance of anti-wear hydraulic oil directly affects the lubrication effect of related components of hydraulic system, and is an important quality index of anti-wear hydraulic oil. The quality of products should be evaluated by gear machine and vane pump test according to national standards. In the field operation, the Pb value of four ball test is often used instead. Although it is feasible, the criteria need to be accumulated in the work.

China lubricating oil network is your assistant in oil inspection and management. In recent years, the oil testing department of China National lubricating oil network, in combination with the famous testing centers, wholeheartedly analyzes and dissects the performance of lubricating oil for users of Guangfa.