Properties of Lubrication – 1    

·         The properties of lubricants are

Answer: The properties of lubricants are
a) viscosity
b) flash point
c) fire point
d) cloud point
e) pour point
f) corrosion
g) physical stability
h) neutralisation number
i) film strength
j) oiliness
k) emulsification
l) chemical stability
m) adhesiveness
n) specific gravity.

·         ____________ is the ability of the oil to resist internal deformation due to mechanical stresses.

Answer: Viscosity is the ability of the oil to resist internal deformation due to mechanical stresses and hence it is a measure of the ability of the oil film to carry a load.

·         A more viscous oil can carry a greater load, but it will offer great friction to sliding movement of the one bearing surface over the other.

Answer: True

·         Viscosity varies with the temperature and hence if a surface to be lubricated is normally at high temperature it should be supplied with oil of a higher viscosity.

Answer: True

·         The viscosity is measured by

Answer: The viscosity is measured by viscosimeter.

·         A high viscosity index indicates relatively ____________ changes in viscosity of the oil with the temperature.

Answer: smaller

·         Pour point is the lowest temperature at which the lubricating oil will flash when a small flame is passed across its surface.

Answer: Actually, flash point is the lowest temperature at which the lubricating oil will flash when a small flame is passed across its surface.

·         The flash point of the oil should be sufficiently high so as to avoid flashing of oil vapours at the temperatures occurring in common use.

Answer: True

·         ____________ is the lowest temperature at which the oil burns continuously.

Answer: Fire point is the lowest temperature at which the oil burns continuously while viscosity is the ability of the oil to resist internal deformation due to mechanical stresses.

·         ____________ is the lowest temperature at which the lubricating oil will pour.

Answer: Pour point is the lowest temperature at which the lubricating oil will pour while fire point is the lowest temperature at which the oil burns continuously and viscosity is the ability of the oil to resist internal deformation due to mechanical stresses.