Influence of Temperature on the Rheological Properties of ISO Lubricants

The lacking of normalized conditions in tribological tests has been motivated the researches of this area to establish many experimental conditions in order to obtain a larger comprehension of their phenomena. This paper presents values of constants of Walther equation, which establish the viscosity-temperature relation, for ISO lubricants, destined to a wear testing (sphere against plan), where it will be studied the influence of temperature, and other factors, on wear mechanism by contact fatigue. This kind of wear is the main cause of fail in rolling and gear components. The constants of this equation can be related with temperature, admitted constant pressure, since the viscosity determined using a Brookfield equipment of coaxial cylinders. The calculation of oil constants was performed with the data obtained with variation of testing temperature, from 35 up to 45 °C. 40 °C corresponds to the normalized temperature that specifies the class of viscosity of a specific lubricant. The obtained results will be used to define the testing conditions for contact fatigue equipment and also to the theoretical calculation of minimum oil layer, which defines the lubrication regime.