Lubricating grease knowledge treasure book

Classification of lubricants:

(1) Liquid lubricants&flash& Flash; I.e. lubricating oil

(2) Semi Solid Lubricants&ndash& Flash; I.e. lubricating grease

(3) Solid lubricants&flash& Flash; Graphite powder

The most common ones on the market are lubricants and greases.

The difference between lubricating grease and lubricating oil:

Definition of lubricating oil:

It is a liquid lubricant used on various types of machinery to reduce friction and protect machinery and machined parts. It mainly plays a role in lubrication, cooling, rust prevention, cleaning, sealing, and buffering.

Composition of lubricating oil: base oil+additives

Base oil:

Type 1 oil is directly distilled from crude oil

Type 2 oil is subjected to simple hydrogenation treatment

Type 3 oils are subjected to deep hydrogenation treatment

Type 4 oil refers to the synthetic base oil of polyolefins

5 types of oils are base oils other than 1, 2, 3, and 4 types, such as synthetic ester oils, alkylnaphthalene, etc

Additives: antioxidant, friction improver (also known as oily agent), extreme pressure additive, detergent, dispersant, foam inhibitor, anti-corrosion and rust inhibitor, flow point improver, viscosity index improver

Definition of lubricating grease:

It is a thick grease like semi solid used for lubrication and sealing in the friction part of machinery. It is also used on metal surfaces to fill voids and prevent rust. It is mainly composed of mineral oil (or Synthetic oil) and thickener. Many parts of automobiles and construction machinery use lubricating grease as a lubricating material, commonly known as butter.

Composition of lubricating grease:

Base oil+thickener+additive

Thickening agent: It is a special structural framework formed by solid substances with thickening effect in lubricating grease. The base oil is adsorbed and fixed in the structural framework, forming a semi solid lubricating grease with plasticity.

Additives: friction improver (also known as oiliness agent), extreme pressure additive, rust inhibitor.

The difference between lubricating grease and lubricating oil

Insufficient lubricating oil:

(1) Poor high-temperature resistance& Flash; Volatilization occurs when used at temperatures above 100 ℃, resulting in a short service life

(2) Poor adhesion performance& Flash; Easy to flow and drip on bearings

Characteristics of lubricating grease:

(1) Excellent adhesion performance&flash& Flash; Non flowing, easy to use, and resistant to detachment when applied

(2) Excellent high-temperature resistance and service life

Summary: Lubricating grease is widely used due to its good viscosity temperature characteristics, long service life, low consumption, good extreme pressure performance, simple lubrication structure, and sealing, buffering, and noise reduction effects. For general bearings, lubricating grease has gradually replaced lubricating oil and is the preferred lubricant in modern industrial production.

Traditional lubricating greases include calcium based grease, sodium based grease, composite lithium based grease, etc. Their characteristics are as follows:

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Through the comparison of the performance of traditional lubricating grease above, we can understand that traditional lubricating grease has a short service life, and mechanical equipment requires frequent maintenance and replacement of lubricating grease, greatly affecting production efficiency.

Based on the shortcomings of traditional lubricating grease such as high temperature resistance, water resistance, poor extreme pressure performance, and short service life in harsh environments, our company has developed a series of lubricating grease products. This series of lubricating grease can greatly extend the operating cycle of the equipment and improve production efficiency while meeting customer process requirements. At the same time, due to its more stable lubricating performance during use, the equipment is better protected, Effectively extending the service life of the equipment.

Meaning of lubricating grease indicators

Cone penetration: reflects the degree of softness and hardness

Cone penetration refers to the depth, in units of 1/10mm, at which the standard cone (150g) of the cone penetration meter vertically sinks into the lubricating grease sample within 5 seconds under the specified temperature and load. The greater the cone penetration, the softer the lubricating grease.

Dropping point: reflects high temperature resistance

Dropping point refers to the minimum temperature at which lubricating grease changes from solid to liquid, in ℃; It is one of the indicators used to reflect the high-temperature performance of lubricating grease.

Corrosion resistance: reflects the protective performance of metals

The corrosiveness test of lubricating grease is an indicator to check whether lubricating grease corrodes metals.

The corrosion resistance of lubricating grease is particularly important for protective lubricating grease.

Measure the corrosion performance of lubricating grease The commonly used methods include the GB/T7326 copper strip corrosion test method and the GB/T0331 lubricating grease corrosion test method (T3 copper strip, 45 # steel strip). They all insert the test metal sheet into the lubricating grease, take out the metal sheet at the specified time and temperature, observe the color change of the metal sheet, and compare it with the standard color plate to determine the corrosion level or qualification of the lubricating grease.

Extreme pressure: reflects the lubrication performance under heavy load conditions

The indicators that reflect the advantages and disadvantages of extreme pressure wear resistance performance of lubricating grease are: maximum no bite load PB value and sintering load PD value

Maximum non seizure load PB: The maximum load at which a steel ball does not experience seizure under lubrication at a certain temperature and speed. The higher the measured value of this indicator, the better the lubrication performance of the lubricating grease.

Sintering load PD: Gradually increase the load at a certain temperature and speed. When the upper and lower steel balls undergo high-temperature sintering due to excessive load, the equipment has to stop operating under the sintering load. The higher the sintering load, the better the extreme pressure lubrication performance of the lubricating grease.

Four ball machine: testing the maximum non jamming load PB value and sintering load PD value

Steel mesh oil separation (SH/T 0324-92): reflects stability

Under the condition of 100 ℃, maintain for a certain period of time (30 hours), and the lubricating grease presses out the mass fraction of the base oil based on its own weight, in units of w/w%; Used to reflect the colloidal stability of lubricating grease under high temperature conditions.

Oxidation stability: reflects antioxidant capacity

The oxidation stability of lubricating grease refers to its ability to resist the action of air (oxygen) and maintain its properties without permanent changes during storage and use, which is called oxidation stability.

The oxidation of lubricating grease can lead to the production of acidic substances, which corrode metals during the use of lubricating grease.

The commonly used oxidation stability testing method is the oxygen bomb method, which is SH/T0325-92. It involves loading a certain amount of lubricating grease into an oxygen bomb filled with oxygen pressure (0.8MP), undergoing oxidation at a temperature of 99 ℃, and determining the oxidation stability of the lubricating grease after a specified time (usually 100 hours) based on the corresponding oxygen pressure drop.

Water leaching loss: reflects water resistance performance

Using a water spray testing machine, control the water temperature (38, 79) and spray water at a certain flow rate (5ml/s) onto the bearing coated with lubricating grease for rotation (600r/min).

After one hour, measure the amount of lubricating grease washed down by water. The smaller the amount, the better the water resistance.

Usage of lubricating grease

The grease needs to be used properly according to the site conditions and the characteristics of the grease itself. Under normal circumstances, if the greasing cycle is long and the viscosity of the lubricating grease is hard, use a refueling gun to inject it; If the greasing cycle is short, the grease consistency is thin, and the surrounding environment of the lubrication point is harsh, use an electric or pneumatic grease supply pump to inject; If there is no grease adding equipment on site, manual coating can also be used.

Precautions for use and storage

1. To achieve the best lubrication effect, all residual old grease needs to be removed or extruded before using grease.

2. Different series of lubricating greases should not be mixed to avoid affecting their performance.

3. The packaging cover of the used lubricating grease should be tightly covered to prevent contamination and drying.

4. Store in a cool and dry place, away from sources of ignition



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