What Is The Cause Of The Grease Drying?
1.Grease is contaminated: dust, dirt, floating dust and similar impurities, which can cause the grease to dry out.
2.Incompatibility between greases: If the grease is accidentally mixed, the colloidal structure of the grease will be destroyed and the oil will be accelerated. One of the typical examples is the mixing of organic bentonite grease and soap base grease.
3.High temperature volatilization: the grease formulated with low viscosity base oil is most volatile. When the temperature rises to a certain height, the base oil overflows from the thickener, and the grease gradually hardens (the ratio of the base oil content/thinning agent becomes smaller, and the viscosity of the base oil increases).
4.Oxidation of the base oil: The base oil looks like asphalt after oxidation, and the same oxidation process occurs in the grease. Figure 1 shows that at room temperature, the metal wear debris (containing divalent copper ions) entering the grease causes the oxidation of the grease to increase. Copper accelerates the oxidation of the grease base oil, causing the grease to thicken and harden.
5.Machine parts overheating: if the bearing is filled with too much grease, mechanical conditions caused by overheating (improper installation, heavy load, etc.), insufficient lubrication can cause overheating problems in the machine operation, which, the lubrication Hyperlipidemia is a common cause. When the machine is running at high temperature and reaches the dropping point of the grease, the oil begins to precipitate. The grease gradually loses the base oil and begins to dry. Finally, the grease fails and the machine will have problems.
6.The base oil is extruded by mechanical force: some rolling bearings are prone to oil separation problems, such as spherical rolling bearings. In the rolling shear of bearings and gears, the grease base oil is quickly separated from the thickener. The whole process is like the sponge that sucks the water is wrung out, and some thickener can suck the oil back. Some do not, such as composite aluminum soap has a good resilience, when the pressure is reduced, the base oil can quickly return to the thickener.
7.Hydrostatic extrusion: Under continuous pressure, hydrostatic force will also cause grease to separate oil. The countermeasures are: using a special thickener, a polar base oil, a viscosity index improver, a tackifier, and increasing the concentration of the thickener.