Is lubricating grease to equipment like blood in the human body? Through the detection of various indicators, the operating status and wear of the equipment can be predicted to reduce losses? And what are the differences between lubricating oil testing and grease testing? Come check it out today! Quality indicators of grease detection: basic detection characteristics such as appearance, dropping point, penetration, free acid and alkali, water content, mechanical impurities, etc., to judge the quality of grease.
1. Appearance The appearance of grease is an inspection item controlled by visual inspection and sensory inspection. The main contents of appearance inspection include color, brightness, transparency, fiber structure and uniformity.
2. Dropping point The dropping point, also known as the dropping point, refers to the temperature (°C) at which the grease begins to drop the first drop after being heated and melted in the dropping point tester. The drop point determines the maximum temperature of the grease to a large extent. Generally, the grease should be used at a temperature 20-30°C lower than the drop point. Otherwise, the grease will not be able to maintain normal lubrication if it is melted or softened too much.
3. Cone penetration Penetration, or consistency, is a measure of the firmness of a grease. Penetration is specified by a Ricarson Penetration Meter, which is expressed by the depth to which the standard cone of this instrument sinks into the grease in 5 seconds, in units of 0.1 mm. If the grease is too soft, it is easy to thin and run off; if it is too hard, the fluidity is poor, and it cannot meet the requirements of high-speed rotation and pumping.
4. Moisture Moisture refers to the water content (weight) % of the grease. It exists in two forms, one is bound water, which forms hydrate crystals with soap, which is essential for some greases and can play a role in The role of peptizer and stabilizer; the other is free water, which is adsorbed or mixed in the grease. The content is very small and generally not allowed, because the free water will reduce the mechanical stability and chemical stability of the grease. At the same time, it also reduces its protective performance and even causes corrosion.
5. Free base and free acid Free acid-base refers to the unsaponified excess organic acid content and excess alkali content in the grease. It is good for a very small amount of free base to exist in the grease, but it should not be too large. Too much free base will deteriorate the colloidal stability of the grease; on the contrary, if the free base is too small or acidic, the grease may become soft and easy to become thinner and thinner. churn.
6. Mechanical impurities Residues in the grease insoluble in petroleum ether, benzene alcohol solution and hot distilled water are called mechanical impurities. It is mainly non-oily inclusions and minerals, which are extremely harmful substances in use, and are often prone to wear and tear of mechanical equipment.
The main performance indicators of lubricating oil testing: viscosity, viscosity index, density and specific gravity, pour point, flash point, anti-emulsification, air release, ignition point, foaming, oxidation stability, neutralization value, corrosion, rust prevention Performance testing, pour point testing, copper corrosion testing, flash point testing, abrasion resistance and extreme pressure testing.
1. Viscosity Viscosity is the most important single performance index of lubricating oil, it is the main factor to form lubricating film, which determines the bearing capacity of lubricating oil. Viscosity can be divided into kinematic viscosity, dynamic viscosity, Enn's viscosity, Rey's viscosity and Saybolt viscosity; among them, kinematic viscosity is the most commonly used viscosity expression for lubricating oil.
2. Viscosity index Viscosity Index: is an experimental value used to indicate the degree of oil change with temperature. The viscosity of a liquid decreases with increasing temperature, and the higher the viscosity index, the less the oil changes with temperature.
3. Density and specific gravity The density of a liquid usually refers to the mass of the liquid per unit volume (commonly used unit kg/m3) when the temperature is 15 °C; the specific gravity is also called relative density, which refers to the density of the liquid at 15 °C and the same volume of water at the same temperature. lower density ratio.
4. Pour point The minimum temperature at which the cooled oil can flow.
5. Flash point It is a comprehensive indicator of the fire hazard of a substance and should generally be higher than 20-30°C.
6. Anti-emulsification Refers to the ability of oil to separate from water, also known as water separation.
7. Neutralization value Neutralization value actually includes total acid number and total base number. However, unless otherwise noted, the "neutralization value" generally referred to actually only refers to the "total acid value", and its unit is also mgKOH/g.
