Understand the importance of the chemical properties of the grease for practical knowledge - bearing

Mainly includes the oxidation stability, free acid and alkali, corrosion resistance, etc. 1, oxidation stability, grease resistance to oxidation in the process of storage and use. Oxidation stability is one of the important performance influence the service life of grease, especially for long-term use under high temperature grease. 2, free acid and alkali, free acid and alkali is refers to the grease in the process of production without sufficient amount of organic acids and excess alkali after saponification. The mass fraction of free alkali content with KOH. Free organic acid and alkali in the sense of use: 1) Very small amounts of free alkali has a little influence on quality of grease, allowing even must contain a small amount of free alkali. Grease in long-term storage, due to oxidation, after some hydrocarbons metamorphism, become the organic acids, reducing, and it makes free alkali content. So it is necessary to the existence of a certain amount of free alkali, can inhibit the oxidation of the grease. But contains large amount of free base grease, the grease colloid stability and mechanical safety will be affected, creates a layered, analysis of oil and lubrication performance loss. 2) Grease does not allow the existence of free acid, especially low molecular organic acids, can produce corrosion to metal. Acidic, grease will disable fat skeleton, fat has become loose. 3, corrosive: grease are corrosion effect on metals. Grease on metal corrosion causes mainly include: one is itself contains corrosive substance, such as water, free acid, alkali and active sulphur, etc; Another reason is due to oxidation of organic acids. ( 3) Practical performance include: mechanical stability, lubricity. 1, mechanical stability: refers to the grease is mechanical force and its structure was damaged and consistency change performance. With the strength of shear cone into the before and after changes in value. 2, lubricity, grease lubrication performance very close to its use and the heavy equipment, chain and gear, in particular, it must have high comprehensive wear value and sintering load, to prevent performance can not meet the requirement and make the equipment wear and tear. Assess the anti-wear and extreme pressure properties of the grease of the most commonly used method is a four ball machine and ladder, Ken tester method.