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	PETROLEUMS PVT. LTD.
E-10 NANDDHAM IND. ESTATE.,
MAROL MAROSHI ROAD, ANDHERI (E)
MUMBAI (INDIA)
Tel: 91-22-2850 0705 Fax: 91-22-5693 8662
E-Maol : 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