1. specific gravity: certain quality of lubricating oil at 15 ° c and the volume of the same volume of water at 4 ° c the quality ratio. Densities increase with their relative molecular weight of hydrocarbons increased molecular weight are the same, according to alkanes, isomeric alkanes, cycloalkanes, aromatic hydrocarbons in order to increase. At the time of specific gravity and density, you need to indicate the determination of temperature.
2. viscosity: are liquids within the friction, lubricant when the relative motion occurs in the role of external forces, the resistance to lubricating oil between oil molecules cannot be smooth flow, the size of the resistance as a viscosity. Most of the classifications according to the viscosity of lubricating oil, which is the main indicator of various machinery and equipment selection of oil. Poor flow properties of high viscosity lubricating oil, cooling and flushing action is poor, higher temperature of the friction surface, its carrying capacity better; smaller viscosity lubricating oil instead. Therefore great care when choosing a lubricant must select the appropriate viscosity.
Into relative viscosity and absolute viscosity measurement viscosity. Absolute viscosity divided into dynamic viscosity kinematic viscosity: relative viscosity has multiple representations: ernsts viscosity viscosity, match, Ray′s viscosity. Kinematic viscosity of dynamic viscosity divided by the density of lubricating oil. Relative viscosity and absolute viscosity conversion between. Dynamic viscosity units: PA s (Pa.s) or Hoa Pa•s (mPa.s): kinematic viscosity units: meters per second (m/s), but commonly used CST (cSt) (mm/s).
3. viscosity index: is a lubricating oil viscosity changes with temperature indicator. High viscosity index, viscosity of the lubricant as the temperature tends to change less, namely viscosity of temperatures rise to a smaller tendency of small, temperature decreases viscosity and tendency to grow smaller. Viscosity index by 40 ° c and 100 ° c viscosity calculation or table available.
4. flash point and fire point: is a security indicator represents the continuous heating conditions, the oil on the surface of steam when a flash fire with flames reaching the minimum oil temperature. Flash point higher instructions oil lit the less likely. Usually open cup flash point method of lubricating oil and light fuel oil used in the 150 ℃ below the flash point closed cup method. The same oil, its open cup flash point closed cup flash point higher 20~30℃. Ignition temperature is the oil continues to experiment after the flash point, until the ignition flame can make the oil ignited and burning for at least 5 seconds minimum oil temperature. General requirements flash point higher than the temperature of the lubricating oil 20~30℃, to guarantee the safety of use and reduced evaporation losses.
5. the tipping point: it is important to low-temperature performance index, says under certain experimental conditions, minimum temperature of the lubricating oil to flow. Oil lost liquidity at low temperatures for two reasons: one is caused by increased oil viscosity at low temperature: the other is the oil wax crystallization at low temperatures, causing oil to lose mobility. Pour point can be added depressant to restructuring, but pour point depressant is not able to reduce total wax content of oil products, just changed the structure of the wax crystals. Long-term storage of oil, pour point of rebound phenomena can occur.
6. the acid value and value or: is index that represents the total content of organic acids in oil. Size of oil acid value has a big impact on its performance. In General, the bigger oil oxidation, acid value larger the more strongly the corrosiveness of lubricating oil, particularly in the presence of water, this corrosive more strongly. Acid number of actual use is typically used to control the life cycle of the fuel and storage period. But for some anti-rust oil due to join acid additive, so larger acid value is normal.
7. the total base number: alkaline substances in lubricants, especially joined alkaline additives in oil, in actual use as a measure of alkaline additives consumption indicators.
8. stability of: lubricating oil under the heat and Catalysis of metal, oxidation resistance ability. Oxidation stability depends on the chemical composition of the oil itself, as well as the conditions of use, such as the media, use of time, humidity, temperature, catalyst. Methods of determination of oxidation stability of different oils.
9. penetration: is a measure of degree of consistency of grease that is soft and hard targets. The prescribed temperature and under load, standard of the cone vertically in 5 seconds sample depth of the cone people sinking into the grease. Cone man larger, more soft lubricating greases. Grease level is divided according to Cone man size.
10. dropping point: grease under the conditions stipulated in the heat, as temperatures rise and become soft, fat drops one drop of temperature in the Cup is called dropping point. It is a measure of heat-resistant lubricating grease indicator. In General, the maximum temperature is lower than dropping point of lubricating grease 30~50℃.