The National Lubricating Grease Institute (NLGI) has established a specified standard classification for lubricating greases. The NLGI consistency number (known as“NLGI grade”)standard for a measure of the relative hardness of a grease used for lubrication. The bigger the NLGI number which means the grease is more firmer/thicker.
Consistency is a measurement of basic physical properties of grease indicating grease hardness, which can be adjusted by changing thickener content.
The NLGI consistency number alone is not sufficient for specifying the grease required by a particular application. Always refer to your owner’s manual for the recommended type of grease.
(Source: https://en.wikipedia.org/wiki/NLGI_consistency_number )
The following table shows the NLGI classification and compares each grade with household products of similar consistency.
NLGI grade ( National Lubricating Grease Institute) NLGI consistency numbers | |||
NLGI | ASTM worked (60 strokes) | Appearance | Consistency food analog |
penetration at 25 °C | |||
000 | 445-475 | fluid | cooking oil |
00 | 400-430 | semi-fluid | apple sauce |
0 | 355-385 | very soft | brown mustard |
1 | 310-340 | soft | tomato paste |
2 | 265-295 | "normal" grease | peanut butter |
3 | 220-250 | firm | vegetable shortening |
4 | 175-205 | very firm | frozen yogurt |
5 | 130-160 | hard | smooth pâté |
6 | 85-115 | very hard | cheddar cheese |
NLGI Grade 000-NLGI 0 greases
Application :NLGI Grade 000-NLGI 0 are recommended for high pressure, heavy-duty and closed system.
Advantages : Outstanding lubricity performance,good pumpability,better heat dissipation.
Disadvantages: Easy to appear oil separation.
NLGI 1- 2
Normally NIGI 2 is the standard and most popular consistency in most of greases,it is normal greases. But in practical applications,different application or different equipments will be required various NLGI grease.
Advantages : Wide range of applications,good colloidal stability
Consistency NLGI grade ≠Viscosity
Customer ask ：i am looking for one thicker greases...
Lubircant factory ：Do you want more “harder”grease or more “stickier” grease?
Customer ：What is the difference between these two?
Firstly NLGI grades (Consistency &Penetration ) is only for Grease products
And viscosity is for lubricating oils or the base oils of greases products.
NLGI grades classify grease soft or hard ,it stand for grease appearance state.
viscosity classify grease base oil viscosity,It determines the grease viscosity，The higher the viscosity,and the grease is more stickier.
Normally 2 greases may have same NLGI grade but very different base-oil viscosities, while two others might have the same base-oil viscosity but dissimilar NLGI grades，that is normal situation in greases products.
That is why we had to understand well customer’s real demand.