Selection of grease

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This post was last edited by Cultivator on 2012-6-20 05:18. When the same kind of mechanical equipment uses different greases, the lubrication and economic effects are different, and the same kind of grease is used on different mechanical equipment, and the effects reflected are also very different. Therefore, the selection of grease must be strictly based on the actual working conditions of the equipment and the performance of the grease. The main factors affecting the use effect of grease 1. Working temperature The temperature and variation range of the lubricating parts have a significant impact on the lubrication effect and service life of the grease. As the operating temperature rises, the life of the grease will be shortened. That is, when the temperature rises, the base oil in the grease will cause evaporation loss and oxidative deterioration, and the colloidal structure of the grease will also change and accelerate oil separation. When the temperature is too high. The colloidal structure will be completely destroyed and the grease cannot be used anymore. If the temperature changes frequently, the gel (soap fiber) skeleton will shrink and separate into oil, which will become more serious. Therefore, when lubricating high-temperature parts, consider choosing grease with good oxidation resistance, small thermal evaporation loss, and high dropping point. Greases used at low temperatures should have low resistance and small relative viscosity. 2. Operating speed The operating speed of components has a great impact on the state of the grease used and its lubrication effect. The faster the rotation speed, the greater the shear stress experienced by the grease, the greater the damage to the grease fiber skeleton formed by the thickener, and the service life will be shortened. When the speed doubles, the life of the grease decreases by a factor of ten or more. For high-speed rolling bearings, grease with a larger consistency is generally used to prevent the bound water in the grease from being thrown out during high-speed operation and affecting the lubrication effect. For bearings whose rotational speed is not too high, in order to reduce motion resistance, low-consistency grease should be used as much as possible. 3. Load When the load on the bearing increases, the life of the grease will decrease sharply. When using grease for heavy-duty machinery, you should choose grease with higher base oil viscosity and thicker consistency, or grease with extreme pressure additives or fillers (such as molybdenum disulfide, graphite). 4. Environmental conditions Environmental conditions refer to the working environment of the lubricating part and the medium it is in contact with. Such as air humidity, dust and whether there are corrosive media, etc. In humid environments or in contact with water, use grease with good water resistance. When conditions are harsh, grease with rust inhibitor should be used. For lubricated parts that are in a medium environment with strong chemical effects, special grease resistant to chemical media should be used. Selection of grease In order to make full use of the performance of grease, when selecting grease, not only the composition, performance and use of the grease must be considered, but also the performance of the mechanical equipment, environment and other working conditions. When choosing grease, please refer to the table How to use grease 1. Manual greasing Manual greasing is mainly used for the lubrication of rolling bearings, open gears, chains and other parts. 2. Top pressure lubrication is suitable for the lubrication of sliding bearings of large equipment, such as steam locomotive shafts, paper machine dryer cylinder shafts, etc. This kind of lubrication usually uses silicone grease lubricating material, which is pressed against the journal through a spring support plate, and the lubrication is maintained by squeezing contact. 3. Grease cup grease is suitable for equipment that is continuously operated for a long time and is regularly greased, such as large and medium-sized metal cutting machine tools, electric motors, water pumps and blowers, etc. When adding grease, just turn the cup cover "() every time to add the appropriate amount of grease to the lubricated part. 4. Grease gun. The grease gun is a piston-type hand pump. The most common ones are direct push type and pressure rod type. When using a grease gun to grease, you only need to install a grease nozzle at the required lubrication part, and then the grease can be sent into the friction part. This approach works on a variety of devices. 5. Centralized lubrication Centralized lubrication is suitable for complete sets of equipment with a large number of lubrication points in large-scale continuous production, and there are certain difficulties in manual greasing, such as steel rolling mills. The centralized lubrication system continuously delivers grease to various lubrication parts through pumps and pipelines, which can reduce maintenance workload and improve reliability. Grease mixture Grease cannot be mixed at will, otherwise the lubrication effect will be affected. The following is an introduction to the effects of several mixing forms on grease.: 1) When the same type of grease is mixed, if it is a product produced by the same factory, the dropping point and cone penetration will not change greatly after mixing. If the products are not produced by the same factory, their properties will change after mixing due to different production processes. 2) After mixing two greases with different properties, the thickener will be unevenly dispersed and it will be difficult to form a stable structure. The grease will become soft and the mechanical stability will decrease. 3) New grease cannot be mixed with waste grease, because waste grease contains a large amount of organic acids, metal particles and other impurities, which will accelerate the oxidation of the grease and seriously affect the lubrication effect. Therefore, when replacing grease, the old grease should be removed. 4) Grease cannot be mixed with lubricating oil at will. If the grease is too dry, the fluidity of the grease needs to be improved. You can add a small amount of lubricating oil when using it, and mix it evenly before use (heating the grease until it melts during mixing is better). 5. Storage of grease In order to ensure the quality of grease, the following aspects must be paid attention to in the storage, storage and transportation of grease. 1. Packaging grease is a colloid system. If it is packaged in a large container, the pressure caused by gravity will cause the lubricating skeleton to be compressed, which will easily cause oil separation, so it is necessary to use a small container for packaging. 2. During transportation, in order to prevent the oil drum from being broken and causing oil leakage, it must be handled with care. In order to prevent the grease from soap and oil separation, care should be taken to avoid excessive vibration or severe squeezing of the grease. During transportation, it is necessary to protect it from the sun and rain, and strictly prevent dust, sand and rainwater from falling into it. 3. Storage and storage: It is best to store grease indoors because the temperature difference is too large, which will destroy the colloidal stability of the grease. If there are no indoor storage conditions, it should be temporarily stored in a place that is windproof, rainproof, dustproof and out of direct sunlight. Grease cannot be stored for a long time, otherwise it will deteriorate due to continuous oil separation of the grease. mxsilence: Based on my own experience, I would like to add some: , v8 z4 ^ * z) i3 t( \2 A shipment: Do not place the packaging barrel upside down or on its side, as this may easily lead to oil separation. ； Storage and safekeeping: After removing the grease, the surface should be smoothed and no holes or pits should be left. It is easy to cause oil separation due to gravity, which will affect the content of the base oil in the grease, thus affecting the lubrication effect of the grease.