Grease Basics
author: Ann
2024-08-20
Basic Concepts of Grease
(1) What is Grease
NLGI (National Lubricating Grease Institute National Lubricating Grease Institute) latest definition: grease is one or more thickeners dispersed into one (or more) liquid lubricant to form a solid or semi-solid product. In order to improve certain properties, some other components (additives or fillers) are added.
(2) Thixotropy of grease
When an external force is applied, the grease gradually becomes softer in the flow, and the apparent viscosity decreases, but once it is at rest, after a period of time (very short), the consistency increases again (recovery), which is the thixotropy of the grease.
This special property of grease determines that it can be lubricated in parts that are not suitable for lubricant lubrication, and shows its superiority.
(1) What is Grease
NLGI (National Lubricating Grease Institute National Lubricating Grease Institute) latest definition: grease is one or more thickeners dispersed into one (or more) liquid lubricant to form a solid or semi-solid product. In order to improve certain properties, some other components (additives or fillers) are added.
(2) Thixotropy of grease
When an external force is applied, the grease gradually becomes softer in the flow, and the apparent viscosity decreases, but once it is at rest, after a period of time (very short), the consistency increases again (recovery), which is the thixotropy of the grease.
This special property of grease determines that it can be lubricated in parts that are not suitable for lubricant lubrication, and shows its superiority.
Composition of grease
Grease is composed of base oil, thickener and additives (including fillers).
The base oil is a liquid lubricant, which can be divided into mineral oil and synthetic lubricant.
Thickener is some solid substance with thickening effect.
Additives are substances added to improve certain properties of grease.
Composition of grease - base oil
1、Mineral oil, which means petroleum lubricant.
Advantages:
Good lubricating properties, wide range of viscosity, different viscosity oils are suitable for the manufacture of different uses of grease; wide range of sources, low price.
Disadvantages:
For high temperature, low temperature can not be taken into account at the same time, or can not adapt to a wide range of temperature, while some of the very high temperature, very low temperature, high speed, long life, chemical media, radiation and other special conditions can not meet the requirements. To meet these harsh conditions of the use of grease, but also need a variety of synthetic oils.
Composition of grease - base oil
2. Synthetic oils
Synthetic oil refers to a large class of functional liquids synthesized by various chemical reactions. Different synthetic oils show better superiority than mineral oils in some aspects.
At present, the synthetic oils commonly used in grease are:
Synthetic hydrocarbon oils, ester oils, silicone oils, fluorine-containing oils, and polyether-type oils.
A variety of synthetic grease because of the use of synthetic oils and have in high and low temperatures, load capacity, oxidation resistance, media resistance, suitable for high-speed, radiation and other aspects of the performance of the superiority, and therefore in the aviation, aerospace and a variety of civil equipment lubrication.
Grease is composed of base oil, thickener and additives (including fillers).
The base oil is a liquid lubricant, which can be divided into mineral oil and synthetic lubricant.
Thickener is some solid substance with thickening effect.
Additives are substances added to improve certain properties of grease.
Composition of grease - base oil
1、Mineral oil, which means petroleum lubricant.
Advantages:
Good lubricating properties, wide range of viscosity, different viscosity oils are suitable for the manufacture of different uses of grease; wide range of sources, low price.
Disadvantages:
For high temperature, low temperature can not be taken into account at the same time, or can not adapt to a wide range of temperature, while some of the very high temperature, very low temperature, high speed, long life, chemical media, radiation and other special conditions can not meet the requirements. To meet these harsh conditions of the use of grease, but also need a variety of synthetic oils.
Composition of grease - base oil
2. Synthetic oils
Synthetic oil refers to a large class of functional liquids synthesized by various chemical reactions. Different synthetic oils show better superiority than mineral oils in some aspects.
At present, the synthetic oils commonly used in grease are:
Synthetic hydrocarbon oils, ester oils, silicone oils, fluorine-containing oils, and polyether-type oils.
A variety of synthetic grease because of the use of synthetic oils and have in high and low temperatures, load capacity, oxidation resistance, media resistance, suitable for high-speed, radiation and other aspects of the performance of the superiority, and therefore in the aviation, aerospace and a variety of civil equipment lubrication.
Composition of grease--Thickener Thickener Classification
Hydrocarbon-based: e.g. ground wax, paraffin, petrolatum, etc.
Soap base: the largest class at present, there are sodium-based, calcium-based, compound calcium, lithium-based, compound lithium, barium-based, aluminum-based, compound aluminum and so on.
Organic: urea compounds, amide compounds, organic dyes, fluorocarbon compounds, etc.
Inorganic: bentonite, silica gel, nitrogen boride, graphite, etc.
Hydrocarbon-based: e.g. ground wax, paraffin, petrolatum, etc.
Soap base: the largest class at present, there are sodium-based, calcium-based, compound calcium, lithium-based, compound lithium, barium-based, aluminum-based, compound aluminum and so on.
Organic: urea compounds, amide compounds, organic dyes, fluorocarbon compounds, etc.
Inorganic: bentonite, silica gel, nitrogen boride, graphite, etc.
What is the shear stability of lubricating oil?
The difference between calcium based grease and lithium based grease
