Main physicochemical properties of lubricating oil

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Main physicochemical properties of lubricating oil

(1) Viscosity

The viscosity represents the measure of the internal resistance of the fluid material, which is the performance of the internal friction force when the liquid flows under the action of external force. The internal friction is large, the fluidity is poor, the viscosity of the liquid is large, otherwise, the viscosity is smaller.

(2) Viscosity index

The viscosity index is a predetermined value representing the characteristics of oil viscosity with temperature. Is an important physical and chemical index of lubricating oil. It can determine the adhesive temperature performance of oil products. The less the viscosity changes with temperature, the higher the viscosity index; the less the oil viscosity changes with temperature, the better the viscosity temperature performance.

(3) density and relative index

Density is the mass of the substance contained in the unit volume at the specified temperature, while the density at the standard temperature of 20℃ is called the relative density. The combination of density and relative density can determine the chemical composition of oil product during storage and transportation, and can determine the change of oil quality according to the change of density.

(4) Flash points

Under the specified conditions, the lowest temperature when the oil product is heated to the steam and the flame contact the fire is called flash point, lightning is divided into two kinds: open flash point and closed mouth flash point. Light weight lubricating oil for fuel for measuring the closed mouth flash point. Heavy lubricating oil test for opening point.

Flash points can be used to judge the composition of the fraction. The lower the flash point, the lighter the composition of the oil fraction, the heavier the composition of the oil fraction, the flammability and evaporation tendency, and whether the oil is deteriorated or diluted by light oil or other substances.

(5) Ash

Ash refers to the non-combustible substances left after burning oil, mainly the substances after burning. The determination of ash can determine the hardness of carbon deposition and the content of additives in lubricating oil.

(6) Water

Water represents the water content in the oil. Moisture can determine whether the moisture content in lubricating oil exceeds the standard; prevent the moisture content from affecting the decline of oil quality.

(7) Oxidation and stability

Oxidation stability refers to the ability of lubricating oil to resist the oxidation of oxygen and keep its properties free from permanent changes. It can measure the antioxidant capacity of oil products; it is also an important parameter for determining oil selection.

(8) Emulsibility resistance

The emulsifying resistance of lubricating oil refers to the properties of oil and water leaving after the emulsification of oil and water. The faster the oil and water separation is, the better the anti-emulsification performance of the oil product is.

(9) Turnout point

Turbidity point refers to the turbidity phenomenon of its brightness and transparency when it reaches a certain low temperature. The main reason is that the wax substances in the oil form solid precipitation at low temperature. The oil with bad turbidity point will lead to the wax suspended material attached to the oil circuit and filter element, resulting in poor oil circuit and affecting the normal operation of machinery and equipment.