Greases are indispensable in certain applications where fluid lubricants cannot be contained effectively. Greases offer several advantages over oils in specific contexts. Grease seals out contaminants is well-suited for incorporating insoluble solid additives like molybdenum disulfide and graphite and excels in stop-start performance because it doesn’t drain away like oil. Most dynamic machine operations rely
American engineers noticed that oil from Texas Gulf crude was much thicker at sub-zero temperatures compared to oil from Pennsylvania crude during World War II. This observation came to light when the U.S. military required large quantities of oil for use in various theaters of the war, including cold environments. Engineers and researchers discovered that
Kinematic viscosity, commonly measured in centistokes (cSt) or mm²/s, is the ratio of a fluid’s dynamic viscosity (cP) to its specific gravity (SG). It represents the time it takes for a specific volume of fluid to flow through an orifice under gravity at a given temperature. Since kinematic viscosity changes with temperature, its value is
Dynamic viscosity measures a fluid’s resistance to deformation by shear or tensile stress, usually in centipoise (cP) or millipascal-second (mPa·s). It describes the internal friction in a fluid layer between moving plates, where higher friction requires more force to maintain movement. Dynamic viscosity varies with temperature, so measurements must include the temperature. Tools like the
Viscosity measures a fluid’s resistance to flow, reflecting its internal friction. High viscosity means the oil is “thicker” or “heavier,” while low viscosity means it’s “thinner” or “lighter.” For example, honey is thicker (higher viscosity) than water. Viscosity inversely relates to fluidity and changes with temperature. Hotter oil becomes thinner, reducing engine protection, while colder
- 1
- 2