How to choose suitable grease in different mechanical working environment
Issuing time:2022-11-08 10:02Author:YIRUNDE GREASE
It is necessary to choose the suitable grease in each mechanical working environment, which is generally selected according to the nature of mechanical work.
For the sake of temperature selection grease, temperature (working temperature and ambient temperature) is a key reference standard. Liquid outflow and liquid shrinkage caused by continuous high temperature is an important reason for the ineffectiveness of grease at continuous high temperature. If the temperature is close to or even exceeds the dripping of grease, it will lead to the qualitative change of grease, oil volatilization, oil separation and outflow; But at ultra-low temperature, the mechanical starting torque is large, and it is usually not easy to run, so the ultra-low temperature of the grease is taken into account. Therefore, in the use of relatively high temperature, should choose the taper degree of filial and heat resistant grease. Such as sodium based lipids, lithium based lipids, compound calcium based lipids or combined aluminum based lipids, sodium bentonite lipids, methylsilicone oil compound calcium based lipids, etc.
The application temperature of the general grease should be 10 ~ 20℃ lower than the drop (the generated grease should be less than the drop of 20 ~ 30℃). When working in a low temperature environment (-20 ~ -60℃), it should generally be used for lubricating grease made of low viscosity mineral oil with suitable cone entry and good low temperature performance, such as No. 2 ultra-low temperature lithium base grease, ester oil - lithium base grease, methyl silicone oil compound calcium base grease, etc.
Due to the coning degree of grease under heavy load for a long time, it is related to the load bearing capacity in use. Grease with a smaller coning degree can bear a larger load than grease with a larger coning degree. Therefore, in the friction surface bearing heavy load or impact vibration load, should choose a little cone entry grease; For the friction surface with light load, grease with relatively large cone entry can be used. The working friction surface in the boundary lubrication environment should be selected with extreme pressure additive grease, naturally, technology development is rapid, now most of the high quality grease are added with extreme pressure antiwear agent special additives.
After all, in the speed ratio reason to choose grease. Because the thermal conductivity of grease is poor, the shaft temperature of high-speed bearings is very easy to rise, so the grease made of low viscosity grease with a larger cone entry degree should be selected. On the contrary, the friction position of low-speed gear operation should be selected with a smaller cone entry grease.
It is also very important that the working atmosphere of the friction position of mechanical equipment in natural conditions is associated with the application of grease. In the damp and cold working atmosphere or the place where there is more contact with water, in order to avoid water cleaning and water, water vapor infiltration into the grease makes the lubricating grease emulsion qualitative change, should choose high water resistance calcium based grease, lithium based grease, aluminum based grease, etc. But can not use sodium base fat, with its poor water resistance, easy emulsion. In places where acid gas and other corrosive substances are very serious, grease or hydrocarbon based grease with corrosion resistant additives should be selected. The chemical stability of hydrocarbon based grease is better than that of soap based grease. In places with large dust, thick grease with high purity graphite can be used.
Choosing suitable grease can greatly improve the service life of mechanical equipment, and reduce the consumption of grease, so as to save unnecessary consumption.