The classification of lubricating grease is very important because of its complex variety and various brands. Gb501-65, which was originally classified according to thickener, can no longer meet the requirements of the development and use of lubricating grease, and was abolished on April 1st, 1988. Gb7631.8-90 specifies the classification system for tebss grease according to the use requirements. This classification system equivalently adopts the ISO classification method and has replaced gb501-65. The grease produced, sold and used has not been fully incorporated into the new classification system. Therefore, in order to explain the specific differences between the old and new classification systems, it is necessary to compare the old and new classification systems.

1. Old classification GB 501-65

Gb501-65 is classified according to the composition of thickeners, that is, it is divided into soap based grease, hydrocarbon based grease, inorganic grease and organic grease.

Soap base is divided into single soap base according to different soaps, such as calcium base, sodium base, lithium base, aluminum base, barium base, lead base and other bases; Mixed with soap base, such as calcium sodium base, calcium aluminum base, lead barium base and aluminum barium base; Composite soap base, such as composite calcium base, composite aluminum base, etc. Various greases in the same group can be divided into several groups, such as industrial, marine, etc., according to their use or use.

The greases in the old classification are named in the following order:

Brand endnote group name or grade name category

Example: No. 1 synthetic calcium base grease (Code: zg-lh)

Including: No. 1 -- brand (cone penetration series number)

Synthesis -- endnote (synthetic fatty acids)

Calcium base -- group (thickener)

Grease -- category (grease)

The codes of lubricating grease are shown in the following order:

Class No. - Group No. - class No. - brand No. - endnote No

Example: Z j-4 s (No. 4 graphite alkyl grease)

Where: z-- class number (fixed code)

J -- group number (the thickener is alkyl)

4-- brand (cone penetration series number)

S -- endnote number (including graphite filler)

Lubricating grease is classified according to the composition of thickener, which has great limitations. Using the same thickener can produce many kinds of greases with different properties. Even if the greases produced by different types of thickeners are difficult to accurately distinguish their properties. Therefore, users will be confused with thickener classification, and it is difficult to select thickener without using experience and finding corresponding standards. The use conditions of lubricating grease can not be seen from the grouping, naming and code, so the lubricating grease standard of this code must be found again. Therefore, it is difficult for users to select correctly, and it is easy to misuse, resulting in lubrication accidents.

2. new classification GB 7631.8-90

1、 Scope of application

This classification standard is applicable to all kinds of greases for lubricating various equipment, mechanical parts, vehicles, etc., and is not applicable to greases for special purposes. In other words, it is only applicable to lubricating grease, but not to special grease for sealing and protection. This classification standard is classified by operating conditions. In this standard classification system, a grease corresponds to a code, which corresponds to the most stringent operating conditions (temperature, water pollution, load conditions, etc.) of the grease in application. In fact, gb7631.8-90 is only a code for lubricating grease grouped according to operating conditions, and this code is composed of five capital English letters.

2、 Description of codes used

(1) L is the category code of lubricant and related products.

(2) Each kind of grease is represented by a code composed of a group of (5) capital English letters, and each letter has its specific meaning.

(3) Classification of lubricating grease

(4) Supplementary notes - indication of water pollution

In the above classification table, the operating temperature and load have been clearly stated, but the water pollution has not been clearly stated. In order to determine the letter H (water pollution), several strict cases of R are specified, which are represented by different letters.

(5) Examples

General lithium grease, according to the provisions in the standard:

Service temperature: 20 ℃ -120 ℃

Water pollution: the loss of water leaching is not more than 10%, indicating that it can withstand water washing; The corrosion resistance is grade L, that is, it can prevent rust under fresh water conditions.

Extreme pressure: there is no extreme pressure performance index specified in the index, that is, it does not have extreme pressure.

It can be seen from the above:

Letter 1 refers to the fixed code of lubricating grease, and the code is x;

Minimum operating temperature: 20 ℃, letter 2 is B;

Maximum operating temperature; 120 ℃, letter 3 is C;

Environmental conditions: rust resistance under water washing conditions, letter 4 is h;

Load condition: non extreme pressure type, letter 5 is a;

Consistency grade: 1, 2 and 3.

Therefore, the classification code of general lithium grease is l-xbcha1,2,3.

3、 Comparison of two classification standards

There is no comparison between the two classification standards. However, due to the long service life of gb501-65, the production and sales of lubricating grease have not been fully incorporated into the new system. In order to explain the problem more clearly and deepen the understanding of the new standard system, a simple comparison is made.

l) Classification principle

Gb501-65 is classified according to thickener, and the first letter of the phonetic alphabet of soap base grease is used as a symbol group.

Gb7631.s-90 is classified according to the operating conditions when lubricating grease is applied.

2) Name and code

The nomenclature and code of gb501-65 are very detailed. From the nomenclature, we can know the type of grease thickener, but sometimes we can't see the type of thickener for special grease. The type and brand of thickener can also be reflected in the code.

Gb7631.8-90 only reflects the code of lubricating grease. It is composed of five English letters. The type of thickener can not be seen from the code, but it can reflect the consistency brand.

3) Scope of application

Gb501-65 can be applied to all greases, whether for lubrication, sealing, protection and other purposes. In principle, a grease can be grouped, named and classified according to this naming, code and classification. Therefore, the more grease grouped, named and coded in gb501-65, the more difficult it is for users to choose.

Gb7631.8-90 is only applicable to greases mainly for lubrication, and greases for other purposes are not applicable to this standard.

4) Selection effect

There are many kinds of greases named in gb501-65. Every grease has its own name. The user cannot see the service conditions from the name and code. It is difficult to know the service conditions without selecting grease. It must be determined according to the standard of grease and experience.

Gb7631.8-90 is classified according to the operating conditions of lubricating grease. As long as the classification table is remembered, lubricating grease can be selected according to the classification. At the same time, the user can choose according to the actual needs, because there are several greases that meet the service conditions. As long as the greases made of different thickeners meet the operating conditions, they are classified into this category for the full selection of the user.

5) Simplified variety naming

Gb501-65 can not simplify the naming of varieties, and will only become more and more.

Gb7631.8-90 can simplify the naming of varieties. Lubricating greases can be classified according to the service conditions, and the varieties belonging to this category can be summarized into a classification number.