Grease in contact with air, will slowly oxidation, the colour will gradually darken, this is a normal phenomenon, high temperature will significantly accelerate the rate of oxidation of grease, so that the grease oxidation black, and in equipment using the wrong grease will also accelerate the grease deterioration, and this part needs to pay attention to when using, then what are the reasons for grease deterioration.

1, the colour becomes black, said oxidation deterioration, if only the surface layer of discoloration, you can scrape the surface layer, can still be used as usual. It is best to check the change of acidity and alkalinity, that is, use phenolphthalein indicator drops on a small amount of grease, mixed well, twist with your fingers, such as red, it means that the grease remains alkaline, if not discolored, it means that the grease has become acid.

Generally speaking, become acidic grease can not be used in valuable instruments to avoid corrosion, but can reduce the standard use, used in the rougher equipment not afraid of corrosion.

2、Chemical deterioration

Grease in the use of the process of heat and promote its oxidation of the reaction, so that the viscosity of the base oil increases, acid value increases, oxide increases, the structure of the thickener damage, resulting in grease softening and a large number of sub-oil and shorten the service life. Similarly, there is also due to oxidative deterioration and hardening, from the metal surface off, grease can not be used again. Therefore, in order to inhibit or prolong the thermal oxidation degradation of lubricating grease, are required to add anti-oxidation additives.

3, the surface of the formation of gel film also belongs to the oxidation phenomenon, especially with dry vegetable oil made of grease, easy to produce this phenomenon.

4, the impact of moisture

Moisture can make some grease emulsion deterioration, and even affect the use of metal parts of the rust performance, moisture can also accelerate the oxidation of grease deterioration, grease softening, thickening, some test results show that, or greedy 0.01% of the trace moisture also has a negative impact on the bearing.

The above is the grease deterioration of the causes of what to share, if you want to know more information, please pay attention to this site.