ENTERPRISES PVT. LTD.

Call us at 91-22-29209201
E-10 NANDDHAM IND. ESTATE.,
MAROL MAROSHI ROAD, ANDHERI (E)
MUMBAI (INDIA)
Tel: 91-22-29209201 Fax: 91-22-66938662
E-Mail : mytol@vsnl.net
 

  INTRODUCTION
 


Grease can be defined as a solid to semi-solid material produced by the dispersion of a thickening agent in a liquid lubricant. Other ingredients may be included to impart special properties to the grease.

Thickener
Lubricating Oil
Additives
5 - 20%
75 - 95%
0-15%

 
  COMPLEX GREASE
 
A complex grease is similar to a regular grease except that the thickener contains two dissimilar fatty acids, one of which is the complex agent. This results in good high temperature characteristics to the final product.
 
  LUBRICATING OIL
 
Because of the high percentage of oil by weight in grease, the oil must be of high quality and the proper viscosity. Light viscosity oils are used for low temperature, low load, and high speed applications. Conversely, a heavy viscosity oil is generally used for high temperature, high load, and slow speed application.
   
   ADDITIVES
 
The most common additives found in grease are as follows:

          = Oxidation Inhibitors
          = EPA Agents
          = Anti-Corrosion Agents
          = Anti-Wear Agents
 

   GREASE CHARACTERISTICS
 
The most important factors affecting the properties and characteristics of a grease are:

          = Amount and type of thickener
          = Oil viscosity and physical characteristics
          = Additives

A grease is expected to:

          = Reduce friction and wear
          = Provide corrosion protection
          = Seal bearings from water and contaminants
          = Resist leakage, dripping, and throw-off
          = Be compatible with seals
          = Repel moisture


 
   GREASE DEFINITIONS
 
Consistency -is the degree of hardness of a grease and may vary considerably with temperature. This has been classified by the National Lubricating Grease Institute (N.L.G.I.) into the following categories:
 
N.L.G.I. GRADE
PENETRATION @ 25°c(1/10th mm)
000
445-475
00
400- 30
0
355-385
1
310-340
2
265-295
3
220-250
4
175-205
5
130-160
6
85-115

Shear Stability - is the ability of a grease to resist a change in consistency during mechanical working. Under high rates of shear, grease structures tend to change in consistency.

Oil Separation - is the percentage of oil which separates from the grease under storage conditions. It cannot predict separation tendencies in use under dynamic conditions

High Temperature Stability - is the ability of a grease to retain its consistency, structure, and performance at temperatures in excess of 125° C


   GREASE PROPERTIES
 
The following chart is designed to help you select a type of grease that will satisfy the intended application.

Properties
Calcium
Lithium
Sodium
Aluminum Complex
Calcium Complex
Barium Complex
Lithium Complex
Polyurea Synthetic
Bentone Clay
Dropping Point °C
80-100
175-205
170-200
260+
260+
200+
260+
250+
None
Max Temp°C
65
125
125
150
150
150
160
150
150
High Temp Use
V.Good
Good
Good
Exc
Exc
Good
Exc
Exc
Exc
Low Temp Mobility
Fair
Good
Poor
Good
Fair
Poor
Good
Good
Good
Mech. Stability
Fair
Good
Fair
Exc
Good
Fair
Exc
Good
Fair
Water Resistance
Exc
Good
Poor
Exc
Exc
Exc
Exc
Exc
Fair
Oxidation Stability
Poor
Good
Good
Exc
Exc
Poor
Good
Exc
Good
Texture
Smooth
Smooth
Smooth
Smooth
Smooth
Fibrous
Smooth
Smooth
Smooth

 
 
 
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