graphite lubricant. Distinctive features
Composition and characteristics
To date, the composition of graphite grease is not subject to strict regulations. Even GOST 3333-80, which replaced the outdated GOST 3333-55, does not establish either the quantitative or qualitative composition of the components used in the manufacture of graphite grease. The standard only indicates the general characteristics of graphite grease type "USsA" and the minimum required properties.
This is used by manufacturers, experimenting with the composition and, as a result, the final properties of the product. Today, the two main components of graphite grease are two substances: a thick mineral base (usually of petroleum origin) and finely ground graphite. Calcium or lithium soap, extreme pressure, antifriction, water dispersion and other additives are used as additional additives.
Sometimes copper powder is added to the graphite. Then the grease is called copper-graphite. The scope of copper-graphite grease is shifting towards long-term protection of contacting surfaces from corrosion with minimal relative displacements. For example, such a lubricant is widely used in threaded connections and various guides.
The characteristics of graphite grease, depending on the composition, vary greatly. For example, the minimum temperature at which the lubricant does not critically lose its properties varies from -20 to -50 ° C. Maximum: from +60 (for the simplest UssA lubricant) to +450 (for modern high-tech “graphites”).
One of the most pronounced properties of graphite grease is a low coefficient of friction. This is achieved thanks to graphite, the plates and crystals of which at the molecular level perfectly glide both relative to each other and on other surfaces, regardless of the nature of these surfaces. However, due to the hardness of individual graphite crystals, this grease is not recommended for use in friction units with high manufacturing accuracy and small gaps between the contacting parts. For example, it has been proven that putting “graphite” instead of other suitable greases (solidol, lithol, etc.) in rolling bearings reduced their service life.
Graphite also determines the conductive properties of the lubricant. Therefore, graphite grease is used to protect electrical contacts from corrosion and increased sparking.
What is it used for?
The scope of graphite lubricant is generally quite wide. Graphite has proven itself well in open friction pairs, in which the speed of relative movement of parts is small. It does not wash out with water for a long time, does not dry out and does not degrade under the influence of other adverse external factors.
In standard cars and trucks, graphite grease is also used quite widely:
- threaded connections - to resist corrosion and sticking of threads;
- ball bearings of the steered wheels - as the main lubricant it is pumped into the body of the bearings and additionally placed under the anthers;
- steering rod joints and tips - used in a similar way with ball bearings;
- spline connections - external and internal splines are lubricated to reduce wear during their mutual movement;
- springs - the springs themselves and anti-creak substrates are lubricated;
- contacts - as a rule, these are battery terminals, a negative wire from the battery to the body and a positive wire from the battery to the starter;
- as an anti-creak layer on contacting plastic and metal surfaces.
Despite the fact that today the market offers a wide range of more advanced and adapted lubricants, graphite is still in demand among motorists. It's a good balance between price and features. The average price for 100 grams of graphite lubricant fluctuates around 20-30 rubles, which is much cheaper than modern lubricant compositions with improved characteristics. And where a high degree of protection is not required, the use of graphite will be the most rational solution.
