List Out Lube Oil Properties

Lubricating Oil Properties
The main function of a lubrication oil is to create and maintain a lubrication film between two moving metal surfaces. The basic properties of lubricant used in ship are

Viscosity: it is the most important property of lubricating oil which depends upon the temperature. Viscosity can be defined as
measurement of fluid internal resistance to flow at a specified temperature. There are two ways to measure a fluid’s viscosity,
namely Dynamic (Absolute) Viscosity and Kinematic Viscosity.

Carbon residue: it is the property of lubricating oil to form carbon residues at elevated temperatures.

Flash point: it is the tendency of oil vapours to ignite. Flash point is important for crank case lube oil which is contaminated by fuel oil leaks.

Oilness: it is the tendency of oil to adhere to the moving surfaces.

Detergency and dispersancy: it is the tendency to colloidally suspend, disperse and wash away any harmful combustion products in the oil.

De-emulsivity: it is the tendency of oil to separate from water in a non misible emulsion.

Foaming: when oil mixing with air resulting in cavitation an over heating.

Pour point: it is the lowest temperature at witch the oil starts to flow by gravity. The oil should be preheated if it is used below its pour point temperature.

Base number: it is the capacity of the oil to neutralize the sulphuric compounds which are formed while using sulphur rich fuel.

Total base number: it is the measure of the alkaline oils. TBN 70 mg KOH/g for cross head engines and 30 mg KOH/g for trunk engines.

 Corrosiveness: it is the tendency of the lubricating oil to oxidize due to the presence of oxygen in the high temperature gaseous surroundings

reference: marine diesel engines by deven aranha

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