Technical Support
GREASE CONSISTENCY
CONSISTENCY of the lubricating grease is very important. A too thick (high consistency grease) will have lower pumpability and smaller ability of the grease to reach in the areas where it needs to lubricate. If a grease is too soft, (consistency too small) then it could leak out and increase grease consumption. The National Lubricating Grease Institute (NLGI) classified greases Consistency after the worked penetration of the grease, which is measured after 60 double strokes working, in the grease worker, at 25°Celsius).
Also greases with consistency in between the NLGI grades can be produced, on request (often is used NLGI 00/000 and also the in-between class Grade “NLGI 2,5”) which is between the consistency for NLGI 2 and the consistency for NLGI 3.
NLGI GREASES CONSISTENCY GRADES
NLGI number represent a scale for comparing the consistency range of greases. The numbers are from NLGI 000 which is semi-liquid to NLGI 6 which is solid. For example:This range of greases and pastes products are intended for the extreme applications such as high power open gears for grinding mills, dryers and rotary kilns, lubrication of rolling element bearing exposed to severe operating conditions and steel industry; special paste for bushings of hydraulic and pneumatic hammer; copper paste for easy assembling/disassembling operations in automotive and industrial applications.
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| NLGI Grade |
Penetration after 60 strokes |
| 000 |
445 - 475 |
| 00 |
400 - 430 |
| 0 |
355 - 385 |
| 1 |
310 - 340 |
| 2 |
265 - 295 |
| 3 |
220 - 250
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Measuring of grease penetration in Verila Lubricants testing laboratory
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The ISO grease classification: ISO 6743-9 – the part ISO 6743-9 L-X
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(Class L - Lubricants; Family X). The reading of the grease specification is the following:
ISO –L –X –symbol 1 –symbol 2 –symbol 3 –symbol 4 -Numbers
Symbol 1 = Lower operating temp. range (see table for Symbol 1, A –E)
Symbol 2 = Upper operating temp. range (see table of symbol 2, A –G)
Symbol 3 = combination of resistance to water washout and rust performance, measured as per the ISO 11007 [EMCOR Test], see bellow table of symbol 3, A –I
Symbol 4 = Load carrying / performance symbol (see bellow table of symbol 4, A –B)
Numbers = NLGI Consistency Class by ISO 2137
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| Symbol 1, states the grease Lowest operating temp. |
Lower operating temp., (°Celsius) |
| A |
0 |
| B |
-20 |
| C |
-30 |
| D |
-40 |
| E |
< -40 |
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| Symbol 2, states the grease Upper operating temp. |
Upper operating temp., (°Celsius) |
| A |
60 |
| B |
80 |
| C |
120 |
| D |
140 |
| E |
160 |
| F |
180 |
| G |
>180 |
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| Symbol 3, states the Water Resistance & Rust Protection |
Water Washout Loss, % |
At this Temperature (°Celsius) |
Rust-prevention Rating |
| A |
No Requirement |
38 |
No Requirement |
| B |
No Requirement |
38 |
1-1 max |
| C |
No Requirement |
38 |
2-2 max |
| D |
< 30 |
38 |
No Requirement |
| E |
< 30 |
79 |
1-1 max |
| F |
< 30 |
79 |
2-2 max |
| G |
< 10 |
79 |
No Requirement |
| H |
< 10 |
- |
1-1 max |
| I |
< 10 |
- |
2-2 max |
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| Symbol 4, states the ability to Lubricate under High Loads, by measuring the weld load in 4 ball test ASTM D2596 or IP 239 |
Four-Ball Weld Load Requirement, (kg) |
| A |
None |
| B |
≥ 250 |
Example of reading of the ISO classification of a grease: VERILA Lithium EP 2 is ISO-L-XCCHB-2. This means: it works in temperatures down to -30 Celsius [letter - C] and up to 120 Celsius [letter - C], with very good water wash out resistance and rust prevention [letter - H], with EP properties [letter - B], in NLGI 2 consistency grade [number 2].
EMCOR Testing Rig in our laboratory
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The DIN Grease Classification: DIN 51502
The reading of the grease specification is the following: DIN 51502–Character 1 –Character 2 –NLGI Grade –Character 3 –Lowest Temperature
| Grease classification based on the applications |
Character 1 |
| Greases for Bearings |
K |
| Greases for Closed Gears |
G |
| Greases for Open Gears |
OG |
| Greases for Friction Bearings / Sealing |
M |
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| Lowest operating temp. |
| -10 |
| -20 |
| -30 |
| -40 |
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| Information regarding additives and Base Oils utilized in the grease |
Character 2 |
| dry lubricants added (MoS2, Graphite, etc) |
F |
| Ester based |
E |
| Fluor hydrocarbons |
FK |
| Synthetic or part synthetic base oil |
HC |
| Poly-glycols |
PG |
| Silicon Oil |
SI |
| EP additive |
P |
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Preparation of 4-ball Wel Load test
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Character 3:
designating upper
operating temp.
and water resistance |
Highest
Operating
temp
Celsius |
Behavior in presence of water
according to
DIN 51 807 Part 1 |
| C |
60 |
0 at 40 Celsius to 1 at 40 Celsius |
| D |
2 at 40 Celsius to 3 at 40 Celsius |
| E |
80 |
0 at 40 Celsius to 1 at 40 Celsius |
| F |
2 at 40 Celsius to 3 at 40 Celsius |
| G |
100 |
0 at 90 Celsius to 1 at 90 Celsius |
| H |
2 at 90 Celsius or 3 at 90 Celsius |
| K |
120 |
0 at 90 Celsius or 1 at 90 Celsius |
| M |
2 at 90 Celsius or 3 at 90 Celsius |
| N |
140 |
Producer specific information |
| P |
160 |
Producer specific information |
| R |
180 |
Producer specific information |
| S |
200 |
Producer specific information |
| T |
220 |
Producer specific information |
| U |
> 220 |
Producer specific information |
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Low Tempearture Flow Pressure Test
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Example of reading of the DIN classification of a grease:
VERILA Lithium EP 2 is KP2K-30 grease according to the DIN 51502.
This means: it is grease for bearings [Character K] with Extreme pressure properties [Character P], of NLGI 2 consistency grade, for temperatures up to 120 Celsius [Character K] and down to -30 Celsius.
The TYPICAL OPERATING TEMPERATURES, PER GREASE TYPES
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A grease Operating Temperature Range for continuous operation depends on many factors:
- continuous or temporary exposure to high temperature,
- relubrication frequency,
- if there are frequent cycles of high to low operating temp.,
- evaporation resistance of the grease, and many more.
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Highest operating temp. depending on product, re-lubrication interval, temperature fluctuations
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Lowest operating temp. of a grease
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This graph has general orientation character only, variations for particular products can occur. Some VERILA greases are specially formulated to be safely applied over or below the values presented in the graph. Please always refer to the Product Data Sheet.
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The Grease DROPPING POINT
The dropping point of a grease measures the temperature at which the grease passes from a semi-solid phase into a liquid state, under the conditions of test and testing temperature. The dropping point range is specific for each type of thickener.
Dropping point is linked to the highest operating temp. that the grease can be used at, but the maximum operating temp. must be significantly lower than the grease's dropping point temperature.
Measuring of dropping point temperature in Verila Lubricants testing laboratory
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