Time: 2013/11/16 14:22:08    Author: 佚名    Hits:

1: Component of Lubricant

Lubricant is composed of base oil and additives. Base oil is the main component that determines the basic properties of lubricants, while additive is an important part of it that can make up and improve the shortage of base oil on performances.

   (1) Base oil:

Base oil mainly consists of two main categories, mineral base oil and synthetic base oil. The mineral base oil is derived from crude oil and its main manufacturing process is atmospheric and vacuum distillation, solvent de-asphalt, solvent refining, solvent de waxing, clay, or added hydrogenation refining. Selecting the best crude oil is the most important aspect for mineral-based lubricating oil’s production. The chemical components of mineral basic oil include high boiling point, high molecular weight hydrocarbon and non-hydrocarbon mixture. Generally speaking, its components are alkane, cycloalkane  , aromatics, naphthene aromatics, as well as oxygen, nitrogen, sulfur-containing organic compounds and plastics, asphalt and other non-hydrocarbon compounds.

  （2）Additive:

Additive is the essence of advanced lubricants nowadays, which can improve its physical and chemical properties, bring it new special properties or reinforce its original characters to meet higher requirements if it is selected correctly and is added reasonably. Choosing additives thoroughly, making it balanced carefully and allocating it rationally are the key elements to ensure the quality of lubricating oil according to the requirements of its quality and the performance. Here are some kinds of common additive: viscosity index improvers, pour point depressants, antioxidants, detergent-dispersants, friction relaxation agent, oiliness solvents, extreme pressure agents, anti-foam agents, metal deactivators, emulsifiers, anti-corrosives and antirust.

2: What is viscosity?

Viscosity is the index of oil’s flowing properties. Its international unit is mm2 / s, also can be used as cSt (CST). The viscosity index of oil reflects its stability while temperature changes. It describes the relationship between viscosity and temperature of petroleum products, which is the characteristic parameters, and is also named ‘VI’ as English Code. The higher the viscosity index is, the lower the viscosity is as the temperature changes. On the contrary, the lower the viscosity index is, the higher the viscosity is along with the changes of temperature.

3. What is pour point?

The pour point is the lowest temperature at which the oil still can flow when it is cooling under the specified standard conditions, which need to be considered while Lubricant is selected .The pour point should be lower than the lowest environmental working temperature about 5℃ to 10℃.

4. What is the flash point ？

The flash point of lubricants is the lowest temperature at which it can vaporize to form an ignitable mixture in air while heat the lubricants under specified conditions. Flash fire would occur when the mixture come across fire. In order to ensure the use of safety and reduce the evaporation losses, the selection of lubricants should be based on the level of flash point according to working temperature, and the general flash point should be higher than the natural temperature about 20℃ to 30℃.

5. What is the acid value?

The acid value of lubricants indicates the quality index of total organic acids (in most cases, lubricants does not contain inorganic acid) in lubricants. It means the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of petroleum products, which has a great influence on the usage of lubricants. High oil acid value indicates high level of organic acids in lubricants, which may cause corrosion of mechanical parts, in particular, the corrosion may be more obvious if the organic acids mix with water. What’s more, the acid value would become higher if the lubricants is oxidized and then turned metamorphic in the process of storage and usage. Acid value is always used to measure the oxidation stability of lubricants or taken as the sign to change fresh oil.

6. What is the Saponification Value（SAP Value)?

Saponification Value is the sign of adding component content into metal processing lubricant oil. The mass of milligrams of KOH required to saponify 1 gram of fat is called Saponification Value, which is the sum of ester value and acid value.