Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease

• Lubricating grease is a plastic lubricant composed of one (or more) thickener and one (or more) lubricating liquid bearing.

Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease

• Physical properties of grease
• Including appearance, dropping point, penetration, colloidal stability, moisture, mechanical impurities and evaporation
• Appearance: including color, brightness, transparency, fiber number, uniformity, odor, emulsification, smoothness, softness and hardness. Meaning of appearance in use:
•  The quality of grease can be generally inferred from the appearance. Such as uniformity, softness and hardness, presence or absence of soap block, presence or absence of mechanical impurities, etc.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
•  Preliminarily identify the variety of lubricating grease. For example, calcium base grease and lithium base grease are fine fiber paste, and sodium base grease is long fiber structure.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• You can understand the adhesion and protection of grease. Such as Vaseline and hydrocarbon grease, with strong viscosity, wiredrawing and adhesion.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• You can also know the mechanical stability of grease, that is, whether it is easy to become thinner by twisting and pressing with your fingers.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• .Drip point: also known as drip point. When heated under the specified conditions, the lubricating grease softens with the increase of temperature. The temperature of the drop from the grease cup is called the drop point. Significance of dropping point in use:
• The drip point can determine the allowable high temperature of the grease when it is used. Generally speaking, the grease should work at a temperature 20-30 ℃ below the dropping point.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• The type of grease can be roughly judged according to the measured dropping point and appearance index identification. For example, the dropping point of calcium base grease is about 70-100 ℃; The dropping point of calcium sodium base grease is about 120-150 ℃; 
• The dropping point of sodium base grease is about 130-160 ℃; When the dropping point is higher than 200 ℃, it is mostly synthetic grease.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• Cone penetration: cone penetration is an index to measure the consistency (i.e. hardness) of lubricating grease. The measurement method is to keep the grease at a certain temperature, expressed by the depth of the standard cone with the specified weight sinking into the grease within 5S. The unit is 1 / 10mm. Significance of cone penetration in use:Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
•  Indicates the consistency of the grease. If the cone penetration is large, the consistency is small. If the cone penetration is small, the consistency is large. To a certain extent, it indicates the load borne by the grease when it is used. The grease with small cone penetration bears a larger load.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
•  Indicates flow performance. The grease with large cone penetration is soft, otherwise it is hard. If the cone penetration is too large, it is easy to lose, and if it is too small, the fluidity is poor. Lubricating grease with too small cone penetration is not suitable for high-speed motion pairs, nor for pipeline pressure grease feeding lubrication devices.
•  Cone penetration can represent the plastic strength of grease, so as to preliminarily understand its ability to resist extrusion and shear, which is convenient for rational use.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• The brand of lubricating grease is divided according to the cone penetration. Therefore, if you know its brand, you can know the range of cone penetration, and if you know its cone penetration, you can know its brand.
• Oil separation: lubricating grease tends to separate oil during storage and use, and lubricating grease with good quality has less oil separation. The oil separation tendency of lubricating oil (also known as colloidal stability) has a great influence on its use.Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• Moisture: moisture refers to the mass fraction of water in lubricating grease. It is used to control the percentage of moisture in the product specification. Significance of water in use:Physical and Chemical Indexes and Composition of Commonly Used lubricating Grease
• There are two forms of moisture in grease. One is structural water, which forms hydrate crystals. This water is the stabilizer of grease, an indispensable component and is allowed to exist in grease. The other is free water, which is adsorbed or mixed in the grease, which is harmful to the grease and will reduce the lubricity, mechanical stability and chemical stability of the grease. If there is too much free water, it will corrode the parts.