Why is the viscosity grade of lubricating oil specified based on the value at 40°C?
Thread Content
Why are the viscosity grades of lubricating oils specified using values at 40°C or 100°C?
Since the viscosity of lubricating oil changes with temperature – it decreases (becomes thinner) as the temperature rises, and increases (becomes thicker) as the temperature falls – various factors related to industrial applications are taken into consideration when establishing ISO viscosity grades. The kinematic viscosity measured at 40°C is used as the basis for ISO viscosity. This is an international standard. Just like the length unit meter, there’s a reason why 1 meter is defined as that length. If originally the length defined as 10 meters had been 1 meter, then 1 meter today would be 0.1 meters. This is why it’s necessary to standardize units of measurement.
I don’t think so; I’m looking forward to a better answer. . .